Toxicities Associated with Adjuvant Radiation Therapy in Atypical Meningioma

While adjuvant radiation therapy (RT) may prolong progression-free survival in resected atypical meningiomas, whether such progression-free survival benefit outweighs potential treatment toxicities remains controversial. Here, we compare the acute and late toxicity outcomes of atypical meningiomas managed with upfront adjuvant RT versus surveillance.

In our prior single-institution retrospective study of 230 patients with resected atypical meningiomas between 2000 and 2015, adjuvant RT was associated with a significantly lower risk of progression/recurrence compared with surveillance (hazard ratio, 0.21; P < .01), with 36% of surveillance patients eventually requiring salvage RT. In this study, the acute (≤6 months) and late (>6 months) RT toxicities from the same patient cohort for those who received adjuvant (n = 51) versus salvage RT (n = 64) were compared. Additionally, treatment toxicity at the last follow-up was compared between the adjuvant RT (n = 51) and the surveillance (n = 179) groups. Toxicities were graded per the Common Terminology Criteria for Adverse Events v5.0.

RT in the adjuvant compared with the salvage setting was generally associated with greater RT toxicities both in the acute (90% vs 69%, P < .01) and late (57% vs 33%, P = .01) setting. While there was no significant difference in grade 3 to 4 acute toxicities, late grade 3 to 4 toxicities were present in 14% of the adjuvant group versus 3% of the salvage RT group (P = .04). Radionecrosis was present in 18% of adjuvant RT versus 8% of salvage RT group (P = .11). Between the adjuvant RT and surveillance groups, any treatment-related toxicity at the last follow-up was greater in the adjuvant RT group (31% vs 15%, P < .01), with a trend toward greater grade 3 to 4 toxicities (8% vs 3%, P = .10). There was no difference in the rate of cerebrovascular accident (4% vs 4%, P = .99).

Adjuvant RT may be associated with greater acute and late treatment toxicities, which can significantly impact the quality of life of patients with atypical meningioma. Potential RT toxicity should be carefully weighed against tumor control benefits in deciding the optimal use and timing of RT.