Cancer Incidence

Part
01
of seven
Part
01

Cancer Incidence: Lifetime Smokers and Elderly

All the requested data is included in the attached spreadsheet and summarized below. As is explained below, there was some small crossover between the requested age brackets and the available data, but we were able to address both nonetheless.

Findings

1. Incidence Rates

  • According to a 2015 publication from the National Institute of Health based on multi-year, comprehensive data collected between 2007 through 2011, the yearly cancer incidence rate among people between the ages of 55-64 in the U.S. was 24.1% (the closest reputable data we could find to the 60-65 age bracket). Thus, we used that rate for the 60-65 age group requested for this research.
  • According to a 2015 publication from the National Institute of Health based on multi-year, comprehensive data collected between 2007 through 2011, the yearly cancer incidence rate among people between the ages of 75-84 in the U.S. is 19.6% (again, the closest reputable data we could find to both the 74-70 and 80-85 age brackets requested). Thus, we used that rate for both of the aforementioned age groups requested.
  • Per the Centers for Disease Control, the odds of U.S. adult smokers getting cancer are six million out of "the 36 million U.S. adults who smoke." That translates into a 16.7% cancer incidence rate among U.S. smokers (6/36 * 100). That was the closest-matching data we could find, as we were unable to locate the incidence rate among the lifetime smoker cohort specifically.

2. Population Counts

  • There were 20.33 million people in the U.S. between the ages of 60 and 64 in 2018 (9.73 million men + 10.6 million women).
  • There were 9.26 million people in the U.S. between the ages of 75 and 79 in 2018 (4.14 million men + 5.12 million women).
  • There were 6.13 million people in the U.S. between the ages of 80 and 84 in 2018 (2.59 million men + 3.54 million women).
  • The aforementioned population counts are also included in the attached Google Doc.
  • According to the Centers for Disease Control and Prevention, 42.1 million adults in the U.S. "are consistent smokers" (the closest population count we could get for lifetime smokers). The aforementioned figure translates into 18.1% of the U.S. adult population.

3. Percentages of Population That Might Develop Cancer

  • The percent of the ages 60-64/5 subgroup (crossover between ages 64 and 65 explained above) that might develop cancer, among the U.S. population, is 1.5% (20.33 million * 0.241 = 4.9 million / 329,485,722 (2019 U.S. population)= 1.5%).
  • The percent of the ages 74/5-79 subgroup (crossover between ages 74 and 75 explained above) that might develop cancer, among the U.S. population, is 2.81% (9.26 million * 0.196 / 329,485,722 = 2.81%).
  • The percent of the ages 80-84/5 subgroup (crossover between ages 84 and 85 explained above) that might develop cancer, among the U.S. population, is 0.36% (6.13 million * 0 .196 = 1,201,480 / 329,485,722 = 0.36%).
  • The percent of the consistent smokers subgroup that might develop cancer, among the U.S. population, is 2.13% (42.1 million * 0.167 = 7,030,700 / 329,485,722 = 2.13%).

Your Research Team Applied the Following Strategy:

We began our research by looking for the cancer incidence rates by age in the U.S. The reputable data that we found was published by the National Cancer Institute, though the age groups varied slightly from those requested. For example, two of the incidence rates provided applied to the 65-74 and 75-84 age groups, while the requested age groups were 74-79 and 80-85. Thus, for the 74-79 age group incidence rate requested, we used the 75-84 incidence rate provided because it covered more years within the requested age group than did the other incidence rate (65-74). We noted the overlapping years in our research findings above, as applicable. The population counts by age group were published by Statista, based on data from the U.S. Census Bureau.

Information about lifetime smokers was difficult to find. With regard to incidence rate among this subgroup, all the data we found either applied to either lung cancer specifically or current smokers. Thus, we didn't find a single data point about incidence rate specific to lifetime smokers or a similarly described subgroup. Accordingly, the closest data point we found was the incidence rate among current smokers, which we thus used. Similarly, with regard to population, we didn't find a single data point specific to the number of lifetime smokers in the U.S. Rather, the closest available data point applied to "consistent smokers" which we thus used.

With regard to the last two data points mentioned, we looked for the exact data points requested (incidence rate among lifetime smokers and number of lifetime smokers) using three strategies. First, we reviewed a substantial quantity of articles published by a combination of media (NBC), governmental (CDC), and health industry (Public Health) sources. Second, we checked to see if there was any mention of such in databases such as Statista, but we didn't come across any such results. As a third strategy, we tried expanding the scope of our searches by looking for data about similarly designated groups, but that also didn't yield any applicable results. For example, we noticed throughout our research that different sources referred to ongoing smokers by different terms, ranging from consistent (term used by the CDC), to lifetime, to lifelong, to consistent, and more. Thus, we used those search terms and similar ones, in order to make every attempt to find the requested about lifetime smokers. Though those terms were used by sources that we reviewed, the data we were looking for was not stated for people who smoke throughout their lives. Since these research strategies didn't yield the exact data points we were looking for, we included the variations of those in lieu thereof, as was noted above.

Some of the sources we used were published in 2015 and 2016. We used those sources in spit of their publication year because (1) they were the most-recent ones we found throughout our research that met the parameters of our research and (2) the sources were very credible (CDC, National Institute of Health). We were actually surprised at the lack of availability of sources regarding incidence rates, as we had expected to find more originally. One limitation we found throughout our research was that many of the incidence rates were specific to one or more particular cancers, while we were searching for incidence rates among cancer in general.

The population counts by age group were from July 2018 and the overall U.S. population value we used was from 2019. We used those values in our calculations involving incidence rates, which were from 2015 and 2016. We did so because we felt that was the best way to calculate the values for Column D of the spreadsheet. Said another way, had we used population counts from 2015 and 2016, the values for Column D would not have reflected the U.S. current population (which we wanted to and did avoid).
Part
02
of seven
Part
02

Cancer Incidence: Genetic Predisposition (1)

The yearly incidence rate of cancers associated with a genetic predisposition in the United States in 2018 was 39.79 per 100,000 people. We have entered the requested information in column B, row 6 of the attached spreadsheet.

CANCER INCIDENCE RATES U.S.

  • The estimated number of new cancer cases in the United States in 2018 was 1,735,350.
  • The estimated number of new cancer cases in people with a genetic predisposition to cancer was 130,162 in 2018. (calculated)
  • The incidence rate of cancer in people with a genetic predisposition to cancer was 39.79 per 100,000 in 2018. (calculated)

RESEARCH STRATEGY

We first started our search by looking for pre-compiled information about the incidence rates associated with cancer in people with a genetic predisposition to cancer. We scanned various pages that provide cancer statistics in the United States including the American Cancer Society, North American Association of Central Cancer Registries, National Cancer Institute and others. These sources mostly provided information about incidence rates and new cases for all types of cancers but there was no data about the number of people or incidence rates related to the genetic predisposition for cancer. We did find that, according to a report by the American Cancer Society, only a small percent of cancers are hereditary.

Next, we searched various government pages, health organizations and research pages including Centers for Disease Control and Prevention, US National Library of Medicine, Research Gate, where we wanted to find the number of new cancer cases associated with genetic factors in the United States. Although these pages provided numerous statistical data, such as rate of new cancers, prevalence, breakdowns by states and other statistics, there was no information about the number people that develop cancer because of a genetic predisposition.

Finally, we scanned different medical news and publications including Medscape, Medical News Today, MedicineNet, Science Daily and others, where we hoped to find information about the percentage of people that develop cancer because of a genetic predisposition. We mostly only found articles about the influence of gene mutations on specific types of cancer, but there was no statistics related to the percent of cancers associated with genetic factors on any of these pages. Since there was no information about the incidence rates associated with cancer in people with a genetic predisposition in the public domain, we decided to use the total number of new cancer cases in the United States and the estimated percentage of cancers that are caused by genetic mutations to calculate the yearly incidence rate.

CALCULATIONS

NUMBER OF CANCER CASES RELATED TO GENETIC FACTORS

Since, 5% to 10% percent of all cancers are caused by genetic mutations we used the average number in our calculations (10% + 5%) / 2 = 15% / 2 = 7.5%
The estimated number of new cancer cases in the United States in 2018 was 1,735,500.

Number of cancer cases related to genetic factors: (1,735,500 * 7.5%) / 100
Number of cancer cases related to genetic factors: 13,016,250 / 100
Number of cancer cases related to genetic factors: 130,162

CANCERS ASSOCIATED WITH A GENETIC PREDISPOSITION INCIDENCE RATE

We calculated the cancer incidence rate by using the following formula:

Incidence rate = (New cancers / Population) * 100,000

The US population in 2018 was 327,096,265.

Cancers associated with a genetic predisposition incidence rate in 2018 = (130,162 / 327,096,265) * 100,000
Cancers associated with a genetic predisposition incidence rate in 2018 = 0.0003979 * 100,000
Cancers associated with a genetic predisposition incidence rate in 2018 = 39.79
Part
03
of seven
Part
03

Cancer Incidence: Genetic Predisposition (2)

While we were unable to find or calculate the number of people that have a genetic predisposition to cancer in the U.S., we were able to calculate the estimated number of people living with a hereditary-caused cancer (people that have a genetic predisposition to cancer) in the U.S. and the additional data requested. The results of our triangulated calculations are included in the attached spreadsheet and explained in detail below.

Findings

1. The Data We Found

  • Estimates show that between "5-10% of all cancers are hereditary."
  • In 2016, the number of people with cancer in the U.S. totaled 15,338,988.
  • The U.S. population in 2016 was 323,015,995. We used the 2016 population count instead of more recent year for uniformity, since our other data point (people living with cancer) pertained to 2016.

2. Our Triangulated Calculation

  • Since between "5-10% of all cancers are hereditary," we used 7.5% as the value for our calculation because it's the average of that range (5 + 10 = 15 / 2).
  • We multiplied the number of people with cancer in 2016 in the U.S. (15,338,988) by 0.075 (representing the aforementioned 7.5%), which equals 1,150,424 (the estimated number of people in the U.S. who were living with a hereditary-caused cancer in 2016, rounded to the nearest whole number).
  • One inherent assumption in that calculation is that the fact since that "5-10% of all cancers are hereditary,"a corresponding 5-10% of people living with cancer have a hereditary-caused cancer. We felt that assumption was reasonable because both values we used (people living with cancer in the U.S. and hereditary cancer prevalence) were overall values.
  • To calculate the estimated percent of the entire U.S. population that was living with a hereditary-caused cancer in 2016, we divided 1,150,424 (estimated number of people in the U.S. who were living with a hereditary-caused cancer in 2016) by 323,015,995 (2016 U.S. population), which equals 0.36% (rounded to the nearest hundredth).
  • Thus, according to our triangulated calculation, an estimated 0.36% of the U.S. population was living with a hereditary-caused cancer in 2016.

Your Research Team Applied the Following Strategy:

We began our research by looking specifically for the number of people in the U.S. that have a genetic predisposition to cancer. After much research, we couldn't find any such directly applicable, pre-calculated value. Thus, we ultimately turned our focus on finding data from which to triangulate the requested values. Based on the available data, the data point we were able to calculate as a proxy was the number of people that were living with a hereditary-caused cancer in the U.S. We decided upon that category because it shows the number of people that developed cancer resulting from hereditary factors, which means they had a genetic predisposition to cancer. One inherent, yet unavoidable, limitation of our calculation is that it doesn't include the number of people in the U.S. that both (1) have a genetic predisposition to cancer and (2) do not have cancer.

Before turning to our triangulated calculation, we looked for the originally requested number of people in the U.S. that have a genetic predisposition to cancer in three different ways. First, we reviewed numerous articles published about genetic predisposition to cancer specific to the U.S. Examples of those sources we reviewed included United Healthcare and the National Institute of Health, among others. The closest data we found from those sources was the hereditary cancer percentage. Before proceeding with that data point (which we ultimately did), we continued our research by consulting the database source Statista, which publishes a wide variety of data specific to the U.S. on many topics, including health-related ones. However, we didn't find the number of people with a genetic predisposition to cancer in the U.S. through that method either.

As a third method, we tried expanding the scope of our research to look for genetic predisposition to cancer rates by country. We thought that by expanding our search parameters (global vs. U.S.), we might find data specific to the U.S. resulting from a broader search. In so doing, we looked at publications from the World Health Organization and Cancer Research UK, but the information applied to specific cancers and thus wasn't for cancer overall. After having implemented those three different search approaches, we concluded that the number of people that have a genetic predisposition to cancer in the U.S. was not publicly available according to our research. Thus, we implemented the triangulated calculation detailed above in lieu thereof.

Lastly, we included an asterisk before each of the values entered in the corresponding row of the spreadsheet to note that the values resulted from triangulated, estimated calculations.
Part
04
of seven
Part
04

Occupations with the Highest Cancer Incidence Rate

Some occupations with the highest incidence of cancer overall in the United States are flight attendants (airline pilots, cabin crews, etc.), veterans, firefighters, miners, etc. Additional statistics on occupations with the highest risk of cancer is in the attached spreadsheet.

FLIGHT ATTENDANTS (AIRLINE PILOTS, CABIN CREWS, ETC)

FARMERS

  • Farmers are 20% more likely to experience cancer when compared to the general population.
  • Cancer rate for the general population = 0.3522% (Calculated)
  • Thus 20/100 of 0.352% = 0.0704%
  • Cancer rate among farmers = 0.3522% + 0.0704% =0.4266%

FIREFIGHTERS

  • Fire fighters have 9% higher incidence of cancer.
  • Cancer rate for the general population = 0.3522% (Calculated)
  • Thus 9/100 of 0.352% = 0.031698%
  • Cancer rate among firefighters = 0.3522% +0.031698% = 0.383898%

WELDERS

  • Welders have 75% higher incidence of cancer.
  • The cancer rate for the general population = 0.3522% (Calculated)
  • Thus 75/100 of 0.352% = 0.26415
  • Cancer rate among welders = 0.3522% + 0.26415% = 0.61635%

MOUNTAIN GUIDES

  • Mountain guides have 57.8% higher incidence of cancer.
  • Cancer rate for the general population = 0.3522% (Calculated)
  • Thus 57/100 of 0.352% = 0.200754
  • Cancer rate among mountain guides = 0.3522% + 0.200754% = 0.552954%

SITTING PROFESSIONALS (E.G. ACCOUNTANTS)

  • Sitting professions (such as book keepers, accountants, etc) have 19% higher incidence of cancer.
  • Cancer rate for the general population = 0.3522% (Calculated)
  • Thus 19/100 of 0.352% = 0.066918%
  • Cancer rate among siting professionals = 0.3522% + 0.066918% = 0.419118%

AGRICULTURE WORKERS

  • Agriculture workers have 35% higher incidence of cancer when compared to the general population.
  • The incidence rate of cancer for the general population = 0.3522% (Calculated)
  • Thus 35/100 of 0.352% = 0.12327%
  • Cancer rate among agriculture workers = 0.3522% + 0.12327% = 0.47547%

ASBESTOS MINERS, ASBESTOS MILLERS, CONSTRUCTION WORKERS, ETC.

  • Several workers in the mining, milling, construction, auto mechanic sector, etc., are exposed to asbestos.
  • Veterans and floor tillers are also exposed to asbestos.
  • Exposure to asbestos "doubles the risk" of cancer.
  • The generalized cancer incidence rate for the US population = 0.3522% (Calculated)
  • Doubled risk = 0.3522% * 2 =0.7044%
  • Thus, miners, millers, construction, auto mechanics, etc., in the asbestos sector all have 0.7044% incidence rate.

RESEARCH STRATEGY

The study included medical industry publications such as Medical Express. We studied occupations/professions with the highest incidence of cancer overall in the United States. We investigated to uncover actual percentages. None of the discovered resources revealed the occupations with the highest incidence of cancer. We also reviewed for occupations with cancer rates higher than the United States average. This strategy uncovered 15% as the cancer rates among flight crews, pilots, flight attendants, etc., and stated that it is above the average cancer incidence rate of the general population. We researched the cancer rates among the general population, but Medical Express did not publish this.

The research also reviewed credible business media publications such as Cheat Sheet (a publication trusted by Yahoo, Facebook, Google, Market Watch, Wall Street Journal, etc.) We studied reports on occupations with the highest incidence of cancer overall in the United States. This strategy revealed about 15 professions known to put Americans at a higher risk of cancer. There were no insights into professions with the highest risks. It stated that only about 4% of US cancer patients could trace the source of their disease to exposure to cancer-causing substances, or carcinogens in the workplace. It also published that agricultural workers (women) have 35% higher risks of breast cancer disease, while the risk in welders is 75% greater. We researched the cancer risk associated with the public, but the Cheat Sheet did not publish this.

We also reviewed other resources such as the American Institute for Cancer research. The research studied the occupations with the highest incidence of cancer overall in the United States. We examined the incidence rate of non-melanoma skin cancer and general cancer among various occupations. We studied to know the occupations with the most significant risk factors by percentage. This information was not included in the cancer data published by country. We also reviewed the standardized rate for cancer incidence among Americans of all ages. This strategy revealed that the United States has 352.2 cases of cancer for 100,000 residents. We researched the breakdown based on gender. Insights were not broken down based on gender. Uncovered insights were said to be relevant to all genders. We calculated the incidence rate among the entire population thus:
Cancer rate in percentage = (352.2 cases /100,000 sampled residents)*100%
Cancer rate for the general population = 0.3522%

The research also reviewed academic and scholarly publications such as Sciencedaily. We studied various occupations, including outdoor professions, for those with the highest risks (rates of occurrence) of skin cancer. Science Daily is a United States-based academic publication. We assumed the study has some relevance to the United States even though the authors may not be Americans. This strategy failed to uncover professions with the highest risk of cancer. We also studied the breakdown details such as the percentage occurrence of cancer among various professions. We intended to compare this with several other rates of cancer associated with specific professions. The study revealed that 26% of mountain guides have skin cancer.

The research also reviewed publications of the National Cancer Institute of the United States. We studied carcinogens (cancer-causing substances) associated with various professions in the United States. We also examined the risk factors associated with exposure to these carcinogens. The institute stated that six minerals known to occur naturally as bundles of fibers are called asbestos and are classified as a carcinogen. However, several industries use asbestos. We studied publications of the Asbestos industry for industry workers at risk of the carcinogen (asbestos). Miners, millers, insulators, boilermakers, auto mechanics, electricians, plumbers, firefighters, construction workers, industrial workers, shipyard workers, and power plant workers have been exposed to asbestos in the United States in the past. We investigated the industries still using asbestos and other carcinogenic substances. The National Cancer Institute and other industry publications did not reveal this information.

We researched Architectural media publications (e.g Architects Newspaper) and publications from industries in construction and manufacturing. We researched the industries using asbestos. This information was not published. The Architects Newspaper revealed that the United States Environmental Protection Agency now allows companies to utilize asbestos-containing products. We also researched local and international publications for information regarding the risk factor of exposure to asbestos. According to Asbestos web, the use of asbestos is banned in over 60 countries, but not within the United States. A Finish web study on asbestos uncovered some risks associated with it. About 20‒30 years exposure to asbestos "doubles the risk of lung cancer." We assumed risk factors of asbestos are universal and applicable in America. We also assumed that asbestos use involves a minimum of mining, milling, etc. It is used in construction, power plant work, etc as revealed by Asbestos web.

To find the occupations with the highest incidence of cancer in the United States, we compared the various rates uncovered and identified the top ten based on rate of occurrence among members of the occupation. Calculations are shown under each profession.
Part
05
of seven
Part
05

Most Common Cancer Screening Tests

Diagnostic imaging tests, lab tests, biopsy, and endoscopy are the most common general screening tests for cancer, according to the Cancer Treatment Centers of America® (CTCA), the American Cancer Society, and the National Cancer Institute (NCI). Under each category lie several other screening tests for cancer; for instance, under the imaging tests category, there are several tests such as mammography, ultrasounds, MRIs, CT Scans, etc., used for screening different types of cancers. However, the tests vary depending on the type of cancer and the needs of each patient; hence, mammograms are popularly used for breast cancer diagnoses while colonoscopy and sigmoidoscopy are used frequently for screening colon cancer.

OVERVIEW OF CANCER SCREENING TESTS

  • While no data is showing the most common cancer screening tests, existing data shows some effective cancer screening tests for the different types of cancers. Therefore, existing research focuses on showing the most frequently used and effective cancer screening tests for the different types of cancers, i.e., prostate, breast, colon, lung, and so on.
  • Research findings also indicate that patients undergo many tests at different points in the process of screening, diagnosis, and treatment of cancer. Thus, it is likely that the tests at each different stage vary. The NCI also prioritizes those screening tests that also help to prevent cancer among people.
  • Below are the most common effective tests used in screening for the different types of cancers, according to reports published by leading cancer organizations, government institutes (NCI), and the medical industry.

MOST COMMON CANCER SCREENING TESTS

COLONOSCOPY, SIGMIODOSCOPY, AND STOOL TESTS

  • Colonoscopy and sigmoidoscopy are tests used to detect early and help prevent colorectal cancer. The tests involve the insertion of a colonoscope or sigmoidoscope through the rectum to observe the colon and rectum. Stool tests involve DNA sampling of patients stool cells to determine any genetic changes.
  • According to the NCI, colorectal cancer was the second leading cause of cancer death in the U.S. in 2016. During that year, approximately 134,490 people were diagnosed with that type of cancer, and 49,190 people would die from it.

LOW-DOSE HELICAL COMPUTED TOMOGRAPHY (CT SCAN)

CHEST X-RAYS

  • Screening with chest x-rays involves an x-ray of the organs and bones inside the chest to take pictures of the areas inside the chest, which are then studied to determine the presence of cancer.
  • Chest X-rays are among the most common screening tests used widely across nations compared to options such as low-dose helical computed tomography, which is highly effective in showing possible early signs of lung cancer among smokers.

CHEST SPUTUM CYTOLOGY

  • Just like chest x-rays, sputum cytology, which involves the examination of sputum coughed up from the lungs under a microscope to check for cancer cells is also a popular lung cancer screening method.
  • While effective in detecting cancer cells in sputum coughed up from the lungs, it does not help prevent lung cancer as is the case with low-dose helical computed tomography.

CLINICAL BREAST EXAMS/REGULAR BREAST SELF-EXAMS

  • Frequent examination of the breasts by health care providers or by women themselves is another popular screening test that is used to detect any lump or other unusual changes in the breast, which will help the patient seek further check-ups.
  • Medical studies indicate that self-breast scans and clinical breast exams do not reduce the chance of dying from breast cancer, which is the second leading cause of cancer-related deaths among women.

MAMMOGRAPHY

BREAST MAGNETIC RESONANCE IMAGING (MRI)

  • Breast MRI is also a popular imaging screening test for cancer, which is commonly used for detecting breast cancer among women who have a high risk of cancer, i.e., women who carry a dangerous mutation in the BRCA1 gene or the BRCA2 gene.
  • MRI procedure uses a magnet, radio waves, and a computer to create detailed images of areas inside the body, especially the breasts, in detecting breast cancer.

PAP TEST AND HUMAN PAPILLOMAVIRUS (HPV) TESTING

PELVIC EXAMS

  • Pelvic exams involve the examination of the vagina, cervix, uterus, fallopian tubes, ovaries, and rectum using a speculum, which is inserted into the vagina and the physician looks at the vagina and cervix for signs of disease. This method is used to test for ovarian cancer.
  • Likewise, physicians can feel the size, shape, and position of the uterus and ovaries by inserting one or two lubricated, gloved fingers of one hand into the vagina and placing the other hand over the lower abdomen. In some cases, the physicians also insert lubricated, gloved fingers into the rectum to feel for abnormal areas or lumps.

TRANSVAGINAL ULTRASOUND

RESEARCH STRATEGY

To find 10 of the most common screening tests for cancer in the U.S., your research team started by looking for any pre-compiled reports showing examples of the most common screening tests for cancer. Unfortunately, we did not find any such report in public. Most reports on cancer focus on the different types of cancers and the types of screening tests used to detect the different types of cancers. Therefore, there, is no one single test that is being used in detecting the different types of cancers; however, every kind of cancer uses different types of screening tests. Our searches across medical journals published by the National Center for Biotechnology Information (NCBI), the National Institutes of Health (NIH), and the National Cancer Institute, did not feature any data regarding the most common screening tests for cancer in the U.S.

In this regard, we relied on data published by the NCI, which included the different types of screening tests for cancer in the U.S. based on the type of cancer. For example, we found out that the screening tests for lung cancer differ from those used in screening for breast or ovarian cancer. Moreover, screening varies depending on the needs of each patient and the stage of the disease, since, some advanced screening tests are recommended in some cancer cases. These attributes make it hard for having standardized screening tests applicable to cancer as a disease, as opposed to the different types of cancers known.

Thus, the examples provided above show the most common cancer screening tests based on the type of cancer under study. Likewise, when viewing cancer diagnosis from a broader perspective, there are only four major screening tests applicable, and they include diagnostic imaging tests, lab tests, biopsy, and endoscopy. Then, under each category are several other categories, which are used in screening for the various types of cancers. Based on the complex nature of cancer screening tests, we decided to focus on the most common cancers known to cause the most deaths such as lung cancer, breast cancer, ovarian cancer, etc. then searched for the common screening tests applicable to each type of cancer.

Based on the new approach, the research team managed to uncover national data published by the National Cancer Institute, showing the most common and effective cancer screening tests for the different types of cancers. We then studied each type of screening and compared it to how many reports mention it to ascertain its commonality. We used additional resources to carry out the comparative checks for the commonality of the tests published by the NCI by examining other sources such as the Cancer Treatment Centers of America® (CTCA), the American Cancer Society, Mayo Clinic, Medicine Net, the American Cancer Society, etc. Through this approach, we managed to determine the common screening tests used for lung cancer, breast cancer, ovarian cancer, cervical cancer, and colorectal cancer.

Overall, our findings show the most common cancer screening tests based on the type of cancer because there are no standardized cancer screening tests for all types of cancers. Each type of cancer uses a different screening and diagnostic approach. For instance, colonoscopy is commonly used in screening for colorectal cancer, while mammograms are effective and used for screening and preventing breast cancer. In closing, current studies indicate the most common cancer screening tests for the different types of cancers.
Part
06
of seven
Part
06

Most Common Cancer Screening Tests (2)

False-positive results occur at a rate of 10% in women that are clinically screened for breast cancer. The number of long-term actual positive cancer cases (true-positive) observed from colonoscopy is 10%. Various test paths (colonoscopy, X-rays, low dose computed helical CT scans, etc.), reveal significantly different rates of false-positives, true-positives, and incidence for cancer. Exposure to X-ray increases the incidence of cancer by 0.6 to 1.8%.

COLONOSCOPY, SIGMOIDOSCOPY, AND STOOL TESTS: FALSE-POSITIVES

  • Out of 30 patients who have undergone stool test via colonoscopy and initially tested positive, seven patients eventually had a negative second test.
  • Thus, the seven patients that are actually negative during the second test indicate (7/30)*100% instances of false-positives uncovered by a single follow up test.
  • Thus, (7/30)*100% = 23.33%.
  • After a second colonoscopy, false-positives noted when compared to initial results = 23.33%.
  • In the final results, only 3 cases are confirmed positive out of 30 initial colonoscopy tests. We have assumed that there is no inconclusive result. The number of false-positive = ((Initial positive results — Final positive results)/Initial Positive results)*100% = ((30-3)/30)*100% = (27/30)*100% = 90%.
  • We could not compute the true- positive/false-positive based on the entire sample. The sample size tested to identify the initial 30 positive results is not made public. The above false-positive/true-positive base on the number of results that change or remain positive following confirmatory tests.

COLONOSCOPY, SIGMOIDOSCOPY, AND STOOL TESTS: TRUE-POSITIVES

  • Out of 30 patients who have undergone a stool test via colonoscopy and tested positive, about 12 patients show a persistently positive result in a second test.
  • The sample size of initial positive candidates = 30, the second test reveal 12 persistent positive results.
  • Thus true-positives based on the second colonoscopy test are: (12/30)*100% = 40% (Assuming none of the positive results confirmed in the second test would eventually become inconclusive.)
  • Out of 30 patients who have undergone stool test via colonoscopy and tested positive going by their first results, seven patients finally had a negative second test result. Repeat evaluation to uncover neoplastic lesions revealed only "3 had positive findings" (confirmed cases) in the long term.
  • Since sample size of initial positive candidates= 30, and the final positive results =3, the true-positive rate based on long term findings = (3/30)*100% = 10%.

COLONOSCOPY, SIGMOIDOSCOPY, AND STOOL TESTS: INCIDENCE RATES

CHEST X-RAYS: FALSE-POSITIVES

CHEST X-RAYS: TRUE-POSITIVES

  • We have assumed that cases of true-positives in chest-Xray patients for the detection of lung cancer =100% — false-positive rate. Thus, 100% — 36% = 64%.
  • Instances of true-positives in chest X-rays conducted to detect lung cancer are 64%.

CHEST X-RAYS: INCIDENCE RATES

  • More than 150,000,000 chest x-rays are conducted every year in the United States. The United States has a population of 329,640,940.
  • Incidence rate of chest X-ray tests = (cases of chest X-rays)*100%/(Population) = (150,000,000*100%)/329,640,940 = 45.50%.
  • The total incidence of cancer determined by X-ray is not available to the public. Limits of X-ray exposure have been a concern to experts. Statistics state that exposure to X-rays increases the risk/incidence of cancer in patients by 0.6 to 1.8%.

CHEST SPUTUM CYTOLOGY: FALSE-POSITIVES

CHEST SPUTUM CYTOLOGY: TRUE-POSITIVES

  • The true-positive rate of chest sputum cytology is 99% as explained below.
  • The false-positive rate for sputum cytology is 1%. The true-positive rate = 100% — false-positive (Assuming we only have two states of positive, i.e., true and false)
  • Thus 100% — 1% = 99%.

CHEST SPUTUM CYTOLOGY: INCIDENCE RATES

  • The identified prevalence of cancer through chest sputum cytology is 0.47%.

CLINICAL BREAST EXAMS/REGULAR BREAST SELF-EXAMS: FALSE-POSITIVES

  • False-positives occur at a rate of 10% in women clinically screened for breast cancer.

CLINICAL BREAST EXAMS/REGULAR BREAST SELF-EXAMS: TRUE-POSITIVES

  • The rate of true-positive in clinical screenings is 90%, as explained below.
  • Since the rate of false-positives is 10% in women clinical screenings for breast cancer, we have assumed that positives have only two states (true-positive and false-positive).
  • Thus, true-positive rate = 100% — false-positives = 100% — 10% = 90%.

CLINICAL BREAST EXAMS/REGULAR BREAST SELF-EXAMS: INCIDENCE RATES

  • The incidence rates of cancer confirmed via breast exams/regular breast self-exams is not available to the public. According to the World Health Organization, screening programs reduce breast cancer mortality among screened groups by about 20% when compared to non-screened groups.
  • In breast screening, false-negatives occur at a rate of 15% to 20%.
  • Thus, (15%+20%)/2 gives an average of 17.5% false-negatives in breast cancer test.

LOW-DOSE HELICAL COMPUTED TOMOGRAPHY (CT SCAN): FALSE-POSITIVES

  • The false-positive results associated with low dose computed helical CT scan is estimated to be 14 out of an entire sample of 1065 patients.
  • The rate of false-positives associated with low dose computed helical CT scan = (14/1065)*100% = 1.314%

LOW-DOSE HELICAL COMPUTED TOMOGRAPHY (CT SCAN): TRUE-POSITIVES

  • The true-positive results associated with low dose computed helical CT scan is estimated to be 327 out of an entire sample of 1065 patients.
  • The rate of true-positives associated with low dose computed helical CT scan = (327/1065)*100% = 30.7%

LOW-DOSE HELICAL COMPUTED TOMOGRAPHY (CT SCAN): INCIDENCE RATES

  • Experts believe the incidence of appendicitis (inflammation of the appendix) is high among young adults in the United States. The total incidence of cancer determined by computed helical CT scan is not available to the public. Although it is debatable, the limits of exposure to helical CT scan waves have been a concern to experts.
  • Computed helical CT scan has high accuracy. Its sensitivity, as well as specificity, is about 96.7%

RESEARCH STRATEGY

The research included academic and scholarly publications, such as journals of the US National Library of Medicine and the National Institutes of Health. We studied cancer testing procedures, including colonoscopy, sigmoidoscopy, and stool tests. We also reviewed chest x-rays, chest sputum cytology, low-dose helical computed tomography (CT scan), and clinical breast exams/regular breast self-exams. We investigated the profile of their positive results, including the number of false-positives, true-positives, and incidence rates. We studied the variation in the screening and incidence rates for various cancer test paths such as colon cancer via colonoscopy, lung cancer through X-ray and sputum cytology, etc. This strategy revealed that screening rates for cancer vary with state. At the state level, the screening rates range from a low of 59% for Wyoming to a high percentage of 75% in Massachusetts. We reviewed the incidence recorded per state for various cancers. We also studied the number of cases that turn out to be false-positive, true-positive, etc.
Part
07
of seven
Part
07

Most Common Cancer Screening Tests (3)

Mammography screening rates in the United States are found to vary by ethnicity and race with an incident rate of 69% for African-American women, 65% for White women, 61% for Hispanic women, 60% for Alaska Native women, and 59% for Asian women. There are over 30.02 million pelvic examinations performed every year in the United States.

MAMMOGRAPHY

MAMMOGRAPHY — FALSE-POSITIVES
  • According to a report published by the Susan G. Komen Breast Cancer Foundation, a woman is more likely of having false-positive results when undertaking several mammograms. It is found that the chance of obtaining a false-positive result after the first mammogram ranges between 7% to 12%, based on the patient's age.
  • The chances of obtaining a false-positive result after ten yearly mammograms are around 50% to 60%. The probability of a false-positive result is found to be "higher among younger women and women with dense breasts".
MAMMOGRAPHY — TRUE POSITIVES
  • For screening mammography, architectural distortion and masses each returned similar results of true-positive and false-positive examination outcomes. Masses resulted in 37% of true-positive result compared to 35% of false-positive result and for architectural distortion, both true-positive and false-positive rates were found to be equal (7%).
  • It was also found that asymmetry was more common in false-positive results with a rate of 26% as compared to its true-positive results of 10%. Calcification indicated frequent true-positive screening results with a rate of 46% compared to false-positive results of the rate of 32%.
MAMMOGRAPHY — INCIDENCE RATES
  • Mammography incidence rates in the United States are found to vary by ethnicity and race.
  • According to the data published by the American Cancer Society, the mammography screening rates of women over 40 are 69% of Black women, 65% of White women, 61% of Hispanic women, 60% of Alaska Native women, and 59% of Asian women.

BREAST MAGNETIC RESONANCE IMAGING (MRI)

BREAST MRI — FALSE-POSITIVES
  • Breast magnetic resonance imaging is the method that has the highest sensitivity in breast cancer detection. It is commonly utilized for various breast imaging indications. According to a study published by the NCBI, the false-positive rates for this test are high primarily because of the limited specificity of the magnetic resonance imaging technique.
  • According to the study, lesions were detected in 414 cases of 986 MRI examinations. And of these, the MRI produced four false-negative results. The sensitivity, negative predictive value, positive predictive value, and specificity of Breast MRI were identified to be 91.7%, 98.7%, 24%, and 69%, respectively.

PELVIC EXAMS

PELVIC EXAMS — FALSE-POSITIVES
  • The United States Preventive Services Task Force found insufficient proof on screening pelvic exams for the detection and treatment of various gynecologic conditions in nonpregnant and asymptomatic adult women.
  • Studies have reported that ovarian cancer's false-positive rates range between 1.2% and 8.6%, and false-negative rates range between 0% to 100%. Women who observed abnormal findings on their pelvic examinations, over 5% to 36% of women underwent surgeries.
PELVIC EXAMS — TRUE POSITIVES
  • Positive predictive value of pelvic exam screening for ovarian cancer is evidently low, and most women who have obtained a positive screening exam result will most commonly have a false-positive outcome.
  • Limited results from pelvic exam studies conducted for ovarian cancer detection reported very low positive predictive values of the range 0% to 3.6%.
PELVIC EXAMS — INCIDENCE RATES
  • Over 30.02 million pelvic examinations are conducted every year in the United States.

TRANSVAGINAL ULTRASOUND

TRANSVAGINAL ULTRASOUND — FALSE-POSITIVES
  • According to a report on the "Screening for Ovarian Cancer: Brief Evidence Update", screening using biannual transvaginal ultrasound resulted in 1.3% of false-positive results.

Research Strategy:

We began our search by looking into various industry-specific reports, government health institutes, and databases such as the NCBI, CDC, MedlinePlus, and the United States Preventive Services for data points on the positive results for the screening tests — mammography, breast MRI, PAP test and Human Papillomavirus (HPV) testing, pelvic exams, and transvaginal ultrasound. An exhaustive search through these channels provided limited information on the positive results profile which includes the false-positive, true positive, and incidence rates of Mammography, the false-positive rate of breast MRI, and the false-positive rate of the transvaginal ultrasound test.

We then expanded our search to include reports on clinical trials and research studies performed on these tests to identify their positive results profile. However, a thorough search through various medical databases indicated a record of a limited number of clinical trials and research studies on the subject. Most of the available information was found to provide a general overview of the tests, product purposes, and alternative/comparable screening tests. There was publicly available information on the true positive and incidence rates of Breast MRI, positive results profile of PAP test and Human Papillomavirus (HPV) testing, and the true positive and incidence rates for transvaginal ultrasound.

We then extended our search further to include several medical health news publications such as Healthline, Mayo Clinic, Cancer.org, Radiology Info, Web Md, and Breast Cancer.org hoping to find cited systematic review of these screening tests. However, the only related data that was found from these channels was the specificity and sensitivity information of these screening tests.
Sources
Sources

From Part 04
Quotes
  • "The number of new cases of cancer (cancer incidence) is 439.2 per 100,000 men and women per year (based on 2011–2015 cases)."
Quotes
  • "Rank Country Age-standardised rate per 100,000 1 Australia 468.0 2 New Zealand 438.1 3 Ireland 373.7 4 Hungary 368.1 5 US 352.2"
Quotes
  • "People who worked with asbestos products are the most at risk of exposure. Occupations that presented the greatest risk of asbestos exposure include: Miners Millers Insulators Boilermakers Auto mechanics Electricians Plumbers Firefighters Construction workers Industrial workers Shipyard workers Power plant workers"
Quotes
  • "Only moderate and heavy exposure, usually 20‒30 years in construction or shipyard work, can cause asbestosis and doubles the risk of lung cancer. However, benign pleural plaques and malign mesothelioma can develop after shorter exposures. Thus there is theoretically no safe limit for asbestos exposure."
From Part 06