And, researchers say, it’s not exactly clear why.
Differences in treatment may mediate some of the association, but biologic sex itself appears to be a stronger risk factor for death, according to the study published online Feb. 8 in Cancer.
The excess in male deaths is “concerning, and we need more clinical data and more biological tumor data within each histologic type of brain tumor to understand why these young adult men who would be otherwise healthy are dying of these brain tumors,” study author Lindsay Williams, PhD, MPH, with the division of epidemiology and clinical research, University of Minnesota, Minneapolis, told this news organization.
Central nervous system tumors rank among the top five cancers diagnosed in young adults aged 20-39 years.
Dr. Williams and her colleagues previously showed that men are more likely to develop brain tumors. Their latest study shows that men die more frequently from brain tumors as well.
Using the National Cancer Database, they identified 47,560 young adults aged 20-39 (47% male) diagnosed with a CNS tumor between 2004 and 2016.
After adjusting for relevant factors, males had a 47% increased risk of dying after a brain tumor diagnosis compared with females (hazard ratio, 1.47; 95% confidence interval, 1.41-1.53).
Males had significantly worse overall survival than females for all CNS tumors combined and for nine of 16 histologic types – namely, diffuse astrocytoma (HR, 1.30), anaplastic astrocytoma (HR, 1.25), glioblastoma (HR, 1.14), oligodendroglioma (HR, 1.37), oligoastrocytic tumors (HR, 1.22), ependymal tumors (HR, 1.29), other malignant gliomas (HR, 1.43), neuronal and mixed neuronal-glial tumors (HR, 1.52), and meningioma (HR, 2.01; all P < .05).
The researchers identified no histologies where females had worse survival.
Five-year survival differed between females and males by at least 5% for all histologies combined (83.2% female and 71.2% male) as well as for diffuse astrocytoma (75.1% vs. 68.5%), anaplastic astrocytoma (63.5% vs. 57.5%), oligoastrocytic tumors (80.2% vs. 74.7%), other malignant gliomas (74.1% vs. 64.9%), and germ cell tumors (92.4% vs. 86.5%).
The researchers estimated that had survival in men been equal to that of women over the study period, 20% of total deaths and 34% of male deaths could have been avoided.
They say future population-based studies are needed to confirm these findings and determine whether tumor biology or responses to therapy are driving forces of the observed male excess in death from brain tumors.
“We cannot discount the role of sex differences in diagnosis, treatment, or behavioral risk factors that may underlie the better survival for women after a brain tumor diagnosis,” they write.
“Hopefully, our research will increase awareness of sex differences in brain tumor outcomes in young adults and encourage other researchers with similar datasets to look at this same question and see if they observe a similar trend,” Dr. Williams said in an interview.
The study was supported by the National Cancer Institute. Dr. Williams has no relevant disclosures. One author, Christopher L. Moertel, MD, is chief medical officer for OX2 Therapeutics, has stock in OX2 Therapeutics, and reports patents relevant to his relationship with OX2 Therapeutics.
A version of this article first appeared on Medscape.com.