Brain cancer is the abnormal growth of cells within the brain, forming a mass or tumor. These growths are categorized as either primary or secondary. Primary brain tumors originate within the brain or its immediate surroundings. Secondary, or metastatic, tumors occur when cancer from another part of the body spreads to the brain. Malignant primary brain tumors are considered brain cancer; they rarely spread to other organs but can invade nearby brain tissue. Understanding these global statistics provides valuable information for researchers and policymakers.
Global Incidence and Prevalence of Brain Cancer
Incidence is the number of new cases diagnosed in a specific period, while prevalence is the total number of people living with the disease. According to 2022 data from the Global Cancer Observatory (GLOBOCAN), there were an estimated 321,731 new cases of brain and CNS cancer diagnosed globally.
The age-standardized incidence rate, which accounts for differences in age structures across populations, was 3.5 per 100,000 people worldwide in 2022. The 5-year prevalence, meaning the number of people alive within five years of their diagnosis, highlights the issue’s scope. Globally, approximately 1.2 million people are living with a brain or CNS tumor.
Worldwide Mortality and Survival Rates
In 2022, brain and central nervous system cancers were responsible for an estimated 248,500 deaths, making it the 12th leading cause of cancer-related death globally. The age-standardized mortality rate was 2.6 per 100,000 people.
A standard metric for prognosis is the 5-year relative survival rate, which estimates the percentage of patients expected to survive for at least five years after diagnosis. For all malignant brain tumors combined, the average 5-year relative survival rate is approximately 35.7%. This rate has seen only marginal improvement over the past few decades.
Survival is influenced by numerous factors, including the tumor type, its grade, its location, and the patient’s age and overall health. For instance, the prognosis for low-grade (slower-growing) tumors is more favorable than for high-grade (faster-growing) tumors.
Geographic and Demographic Disparities
Brain cancer incidence and mortality are not uniform across the globe, with significant geographic and demographic disparities. Age-standardized incidence rates are higher in developed regions like Europe, North America, and Australia, while lower rates are seen in parts of Africa and Asia. For example, Northern Europe and North America have some of the highest incidence rates.
These geographic variations are influenced by several factors. Differences in the availability of advanced diagnostic imaging, like MRI and CT scans, play a part, as countries with developed healthcare systems can better detect tumors, leading to higher reported incidence rates. The quality of national cancer registries also affects data comparability.
Demographic factors like sex and age also show clear differences. For most malignant brain tumors, the incidence rate is higher in males than in females. Age is another factor, with incidence showing two peaks: one in young children and a more significant peak in older adults after age 60.
Statistics by Brain Tumor Type
“Brain cancer” is an umbrella term for over 150 different tumor types, each with a unique statistical profile. These tumors are classified by the cell from which they originate. The most common category of primary brain tumors is gliomas, which begin in the glial cells that support neurons and account for 26.3% of all primary brain tumors.
Within the glioma category, glioblastoma is the most common and aggressive malignant brain tumor in adults, accounting for 14.2% of all primary brain tumors. The prognosis for glioblastoma is challenging, with a five-year relative survival rate of only 6.9%. Other types of gliomas include astrocytomas and oligodendrogliomas.
It is also informative to consider non-malignant tumors, as they can have serious health consequences. The most common primary brain tumor overall is meningioma, which arises from the meninges, the tissue covering the brain. Meningiomas are non-malignant in over 90% of cases and account for 40.8% of all primary brain tumors. Their statistics are tracked because their growth can compress brain tissue, necessitating treatment.