Low Grade Glioma Prevalence
We could neither find nor estimate the number of people globally who suffer from low-grade gliomas. We did, however, find the overall glioma incidence rate for the U.S., as well as several additional data points about the prevalence of low-grade gliomas and other types of gliomas both in the U.S. and globally.
1. Incidence Rates — U.S. & North America
- Per research published by the National Center for Biotechnology Information, there are 20,000 glioma diagnoses in the U.S. annually.
- Gliomas account for approximately 25% of the estimated 80,000 "primary brain tumor" diagnoses in the U.S. annually.
- As one of two types of low-grade gliomas, "[l]ow-grade astrocytomas are relatively uncommon tumors when compared to their higher-grade counterparts . . . [as] about 1,500 are believed to occur in North America each year."
- The diagnosis prevalence for a specific type of gliomas, glioblastomas, is about 12,000 per year in the U.S., which accounts for about 15% of new brain tumor diagnoses in the country annually.
- Among U.S. individuals ages 20-34, "gliomas account for 32% of all primary CNS [central nervous system] tumors, 17% of which are astrocytic tumors; 28% of these are glioblastomas."
- Among U.S. individuals ages 15-39, "[g]liomas account for 29%–35% of the CNS tumors . . ., with approximately two-thirds being low-grade glioma (LGG) and the remaining being high-grade glioma (HGG)."
2. Global Incidence Rate
- We could not find Information about the global incidence rate for low-grade gliomas. One likely reason for that is illustrated in the following statement from the medical industry source Annals of Translational Medicine: "[P]recise information on brain tumors’ epidemiology is poor, since the registration is not mandatory in many countries worldwide. Moreover, brain tumor recording is often limited to malignant tumors, thus excluding non-malignant or borderline ones."
- The incidence rate for a form of low-grade gliomas, diffuse low-grade gliomas, ranges between "3–15% of all brain tumors."
- Diffuse low-grade gliomas account for "15% of gliomas."
- Medical research studies conducted in Europe and America have estimated the brain tumor incidence rate at between 17.6-22 per 100,000 people.
- Another type of glioma is glioblastoma, which "is the most common type of glioma." Glioblastomas "account for 52 percent of all primary brain tumors."
- The annual, global incidence rate for glioblastomas is "2–3 new cases per 100,000 people."
Your research team applied the following strategy:
After conducting thorough research, we concluded that there was insufficient information available from which to directly provide or triangulate the number of people globally who suffer from low-grade gliomas. We looked for that data in three different ways. First, we reviewed many medical research reports about low-grade gliomas published by highly credible industry sources, such as the National Center for Biotechnology Information. That strategy provided us with the U.S. incidence rate for low-grade gliomas, but not the global rate. Those medical research reports also contained insights about the prevalence of low-grade gliomas among certain populations, but information about the global incidence rate itself was not provided nor was there sufficient information to triangulate that value from.
Second, we looked for the global incidence rates for specific types of low-grade gliomas, which include oligondendrogliom and astrocytoma. We implemented that approach because we thought that the global incidence rates for those specific types of gliomas might be available, whereas the global incidence rate for low-grade gliomas as a whole was not. If that information had been available on a global scale, we would have added those values to calculate a triangulated answer to the number of people who suffer from low-grade gliomas. Instead, the information that we found from that approach was for some, but not all, specific types of gliomas, which were diffuse low-grade gliomas and glioblastomas. Since data for all of the types was not available, we couldn't provide a solid estimate of the number of people who suffer from low-grade gliomas based on that data.
As a third research method, we expanded the scope of our research to look for data about the global incidence rate for gliomas in general, instead of low-grade gliomas specifically. We did so because we thought that such data might be more readily available due to its broader scope. We reviewed articles from health industry sources and medical research reports in looking for that information, but the data we found from that approach was the brain tumor incidence rate worldwide, which we included above since it's related to this topic. Due to the limited data available about low-grade gliomas globally, we included the data points that we found about low-grade gliomas and other types of gliomas that we found throughout our research as a proxy. We did so to provide as much relevant information as we could on this topic, despite the limited data available on a global scale.