Summary: Although incidence rates for malignant brain cancers have fallen in recent years, five-year survival for people diagnosed with brain tumors remains low.
Source: American Cancer Society
A comprehensive analysis found that incidence rates for malignant brain and other central nervous system (CNS) tumors in the United States declined by 0.8% per year from 2008 through 2017 for all ages combined. This overall decrease was driven by trends in adults; by contrast, incidence among children and adolescents rose slightly, by about 0.5% to 0.7% annually during the same period.
Published in CA: A Cancer Journal for Clinicians, the report examined current patterns in brain tumor occurrence by looking at incidence, mortality, and survival trends across the U.S. population. The study combined data from the Central Brain Tumor Registry of the United States with national cancer registry and vital statistics sources to provide a detailed, contemporary picture of both malignant and nonmalignant brain tumors.
Although brain and other CNS tumors are relatively uncommon, they represent a substantial share of cancer deaths because of their high fatality. In 2021, an estimated 83,570 people in the U.S. were projected to receive a diagnosis of a brain or other CNS tumor—about 24,530 malignant and 59,040 nonmalignant cases—and roughly 18,000 deaths were expected.
Despite the decline in malignant tumor incidence, overall survival remains poor. Five-year relative survival for all malignant brain tumors combined is only 36%, an improvement from 26% among patients diagnosed in the mid-1970s, but still low compared with many other cancers. The limited gains in survival largely reflect the slow progress in detecting and treating glioblastoma, the most common malignant brain tumor, which accounts for 49% of malignant brain cancers. Five-year survival for glioblastoma increased only from 4% to 7% over the decades covered by the analysis.
Nonmalignant tumor incidence has been rising slowly. These tumors disproportionately affect women and non-Hispanic Black individuals, a pattern that may reflect improved diagnostic practices and greater awareness. For example, meningioma—which makes up 54% of nonmalignant brain tumors in the U.S.—showed an annual incidence increase of 0.9% among adults from 2008 to 2017. Although five-year relative survival for nonmalignant tumors remains high (about 92%), many patients suffer significant, long-term effects from the tumor itself or from treatments they receive.
The analysis also highlights persistent disparities in outcomes among children. Although incidence of childhood brain tumors is lower in Black children than in White children, mortality rates are similar, indicating worse survival for Black children (five-year survival about 70% versus 79% for White children). The largest Black-White survival gaps for children diagnosed between 2009 and 2015 were observed for diffuse astrocytomas (75% vs. 86%) and embryonal tumors (59% vs. 67%).
“Although our molecular knowledge of brain tumor subtypes is expanding rapidly, we still lack a clear understanding of why these tumors arise,” said Kimberly D. Miller, MPH, of the American Cancer Society. “Timely, comprehensive data on tumor occurrence are essential to uncover the causes behind differences by sex, age, and race/ethnicity and to study rarer subtypes and understudied populations.”
Key differences by sex reported in the study include:
- Malignant brain tumor incidence is higher in males (8.3 cases per 100,000) than in females (6.0 per 100,000).
- Nonmalignant tumor incidence is higher in females (20.3 per 100,000) than in males (12.8 per 100,000).
- Sex differences for malignant tumors are most pronounced in people aged 45 and older, where female rates are about 30% lower than male rates.
- For nonmalignant tumors, the largest sex disparity occurs among people aged 25–29, when rates in females exceed those in males by more than twofold (10.2 versus 4.7 per 100,000), a pattern largely driven by higher pituitary adenoma rates in young women.
About this brain cancer research news
Author: Charaighn Sesock
Source: American Cancer Society
Contact: Charaighn Sesock – American Cancer Society
Image: The image is in the public domain
Original Research: Open access. “Brain and other central nervous system tumor statistics, 2021” by Kimberly D. Miller et al., published in CA: A Cancer Journal for Clinicians.
Abstract
Brain and other central nervous system tumor statistics, 2021
Brain and other CNS tumors produce a high burden of morbidity and mortality in the United States. To assess this burden, researchers analyzed population-based data from the Central Brain Tumor Registry of the United States (which combines NPCR and SEER registry data), NPCR, the National Vital Statistics System, and the SEER program. They described tumor patterns by histology, anatomic site, age, sex, and race/ethnicity.
Key findings include a 0.8% annual decline in malignant brain tumor incidence from 2008 to 2017 for all ages combined, with small annual increases among children and adolescents. Malignant tumor rates are highest in males and non-Hispanic White people, while nonmalignant tumor rates are highest in females and non-Hispanic Black people. Five-year relative survival for malignant brain tumors rose from 23% (1975–1977) to 36% (2009–2015), with greater improvements among younger patients. Limited progress among older adults largely reflects the high proportion of glioblastoma, for which five-year survival remains very low (increasing only from 4% to 7% over the same period).
The report stresses that increased resources for consistent, timely data collection and reporting are critical to advance research into the causes of differences by sex, age, and race/ethnicity, and to improve outcomes—especially for rarer subtypes and underserved populations.