Surgery and radiotherapy linked to longer survival in grade 4 brain tumors

Adults treated for central nervous system World Health Organization grade 4 gliomas at two neurosurgical referral centers in the Democratic Republic of the Congo had a median overall survival of 11.8 months in a retrospective multicenter cohort study of 102 patients. During follow-up, 88 patients died, and multivariable analysis found that gross total resection and postoperative radiotherapy were each associated with a lower hazard of death than biopsy alone and no recorded radiotherapy, respectively. The study was published in BMC Cancer and followed patients treated between January 2018 and December 2025.

The cohort included adults with histologically confirmed grade 4 diffuse gliomas treated at the two tertiary referral centers. The median age was 50.0 years, with an interquartile range of 41.2 to 57.0 years, and 64 participants, or 62.7%, were male. Researchers extracted demographic, clinical, surgical, pathological, treatment and available molecular information from institutional records. They estimated overall survival with the Kaplan–Meier method and evaluated factors associated with mortality using multivariable Cox proportional hazards regression. The median overall survival was 11.8 months, with a 95% confidence interval of 11.4 to 12.5 months.

Extent of surgery varied substantially among the 102 patients. Gross total resection was achieved in 29 cases, representing 28.4% of the cohort, while subtotal resection was performed in 51 patients, or 50.0%. The remaining 22 patients, accounting for 21.6%, underwent biopsy alone. After adjustment for measured covariates, gross total resection was associated with a 78% lower hazard of death compared with biopsy alone: the adjusted hazard ratio was 0.22, with a 95% confidence interval of 0.11 to 0.44 and p less than 0.001. Because this was an observational study, the result demonstrates an association rather than proving that surgery alone caused the difference in survival. Access to surgery, postoperative care, disease severity and other unmeasured factors may have influenced the outcome.

Postoperative radiotherapy was also associated with lower mortality in the adjusted analysis. Sixty-five patients received radiotherapy, corresponding to 63.7% of the cohort. Compared with patients who did not receive postoperative radiotherapy, those who did had a 55% lower hazard of death, with an adjusted hazard ratio of 0.45, a 95% confidence interval of 0.28 to 0.73 and p equal to 0.001. This estimate likewise describes an adjusted observational association, not the causal effect of treatment. The findings nevertheless identify two treatment variables that remained statistically associated with survival after multivariable adjustment and point to the importance of coordinated surgical and postsurgical care.

Temozolomide and the molecular measures available to the investigators did not show independent associations with survival. Fifty-four patients, or 52.9%, received temozolomide, but its administration was not independently associated with overall survival in the multivariable analysis. The available biomarkers—PD-L1 expression, Ki-67, MGMT promoter methylation and IDH1 status—also did not demonstrate independent associations with survival. The paper does not establish that these drugs or biomarkers lacked clinical value; instead, it reports that the available data did not support independent associations in this cohort. The authors highlighted the need for improved molecular testing and treatment protocols, noting that incomplete molecular characterization can constrain evaluation of biologically distinct tumors and the therapies used to treat them.

Taken together, the study describes a setting in which survival outcomes for adults with aggressive grade 4 gliomas were linked primarily to access to effective surgery and adjuvant treatment. The results support efforts to strengthen access to safe maximal resection, postoperative radiotherapy and coordinated neuro-oncology services in the Democratic Republic of the Congo. At the same time, the retrospective design, two-center scope and reliance on available records limit generalization and make it difficult to fully separate treatment effects from differences in patient selection, disease characteristics and access to care. The findings therefore provide a real-world clinical snapshot rather than definitive evidence for a treatment protocol.

Subject of Research: Survival and treatment factors among adults with CNS WHO grade 4 gliomas in the Democratic Republic of the Congo

Article Title: Overall survival of CNS WHO Grade 4 gliomas in the Democratic Republic of Congo: a multicenter analysis of 102 patients

Article References: Kamabu, L. K., Darko, K., Ntsambi, G., Fomekong, E., Sikakulya, F. K., Kangitsi, C. K., Lekuya, H. M., Etame, A. B., & Fonkem, E. (2026). Overall survival of CNS WHO Grade 4 gliomas in the Democratic Republic of Congo: a multicenter analysis of 102 patients. BMC Cancer. https://doi.org/10.1186/s12885-026-16909-z

Image Credits: AI Generated

DOI: 10.1186/s12885-026-16909-z

Keywords: grade 4 glioma, overall survival, brain cancer, gross total resection, radiotherapy, temozolomide, molecular biomarkers, Democratic Republic of the Congo, retrospective cohort, Overall, survival, Grade