Adjuvant Radiotherapy Did Not Reduce Recurrence of World Health Organization Grade I Meningiomas with Venous Sinus Involvement: A Propensity Score Adjusted Analysis and Literature Review.

ABSTRACT

BACKGROUND: Most meningiomas are classified as World Health Organization (WHO) grade I. Adjuvant radiation therapy (RT) is commonly recommended for subtotal resections with documented progressive regrowth of lesions with venous sinus involvement. We investigated if recurrence of WHO grade I meningiomas was influenced by adjuvant RT. METHODS: From 2000 to 2014, patients with grade I meningiomas with at least one venous sinus involvement and at least 4 years of follow-up were included. Demographics, venous sinus involvement, histology, and extent of resection (EOR) were characterized. Because patients undergoing RT tend to differ from those for whom adjuvant therapy was not prescribed, we used propensity scores to adjust for confounding variables. RESULTS: Sixty-two patients were included; of these, 18 (29.0%) had recurrences. The mean age was 52.8 ± 12.3 years, and 79.0% were women. A total of 34 cases (54.8%) were submitted to adjuvant RT. Adjuvant RT was more frequent in those who had tumor recurrence (77.8% vs. 45.5%, P = 0.020). RT was more frequent in superior sagittal sinus (SSS) invasion (76.5% vs. 50.0%, P = 0.030) and less prevalent after gross total resection (GTR) (32.4% vs. 67.9%, P = 0.005). Propensity score adjusted analysis suggested no adjuvant RT benefit (odds ratio [OR], 2.51; 95% confidence interval [CI], 0.68-9.28; P = 0.167), independent of the EOR. SSS involvement increased recurrence risk (OR, 12.69; 95% CI, 1.46-110.27; P = 0.021), whereas GTR tended to decrease it (OR, 0.26; 95% CI, 0.06-1.09; P = 0.065). CONCLUSIONS: Adjuvant RT does not seem to be a pivotal criterion to reduce the recurrence rate in patients with grade I meningioma, even when venous sinuses are involved.