The purpose of this study was to describe effects of adjuvant radiotherapy (RT) for anaplastic meningiomas (AMs) on long-term survival, and to analyze patient and RT characteristics associated with long-term survival.
The authors queried a retrospective cohort of patients with AM from the National Cancer Database (NCDB) diagnosed between 2004 and 2015 to describe treatment trends. For outcome analysis, patients with at least 10 years of follow-up were included, and they were stratified based on adjuvant RT status and propensity matched to controls for covariates. Survival curves were compared. A data-driven approach was used to find a biologically effective dose (BED) of RT with the largest difference between survival curves. Factors associated with long-term survival were quantified.
The authors identified 2170 cases of AM in the NCDB between 2004 and 2015. They observed increased use of adjuvant RT in patients treated with higher doses. A total of 178 cases met the inclusion criteria for outcome analysis. Forty-five percent (n = 80) received adjuvant RT. Patients received a BED of 80.23 ± 16.6 Gy (mean ± IQR). The median survival time was not significantly different (32.8 months for adjuvant RT vs 38.5 months for no RT; p = 0.57, log-rank test). Dichotomizing the patients at a BED of 81 Gy showed maximal difference in survival distribution with a decrease in median survival in favor of no adjuvant RT (31.2 months for adjuvant RT vs 49.7 months for no RT; p = 0.03, log-rank test), but this difference was not significant after false discovery rate correction. Age was a significant predictor for long-term survival.
AMs are aggressive tumors that carry a poor prognosis. Conventional adjuvant RT improves local control. However, the effect of adjuvant radiation on overall survival is unclear. Further investigation into this area is warranted.