Top Line: A minority of patients with atypical (WHO grade 2) meningioma receive adjuvant radiation.
The Study: In fact, an NCDB analysis has shown that fewer than 25% of patients get adjuvant RT. That same analysis, though, showed adjuvant RT to be independently associated with better survival. The problem is historically poor data to guide adjuvant therapy and the desire to “defer” the adverse effects of radiation. In EORTC 22042-26042 and RTOG 0539, WHO grade 2 meningiomas had > 90% control at 3 years when adjuvant RT was used. Two ongoing trials are comparing adjuvant RT with observation for GTR’d atypicals. Here is a large analysis of outcomes from patients managed at MGH with surgery followed by either surveillance or RT. In line with national trends, 22% received adjuvant RT. And as you would expect, there was selection bias toward adverse features among those receiving RT. Only ⅓ of RT patients had a GTR compared to ¾ of those who didn’t get RT. Despite those differences, the rate of progression or recurrence was lower (24 vs 36%) and time to progression longer (4.5 vs 1.9 years) after RT than observation. Among observation patients, 36% received salvage RT, which could be just as good an option right? No. Outcomes for salvaged patients were inferior to those treated up-front. The adjuvant RT benefit persisted out to 10 years with a ~10% absolute improvement in progression-free survival at 5 and 10 years. Importantly, though, there was no improvement in overall survival.
TBL: Up-front, adjuvant RT for atypical meningioma regardless of resection (and with selection bias) reduces the risk of recurrence and time to progression even when accounting for salvage RT. | Lee, Int J Radiat Oncol Biol Phys 2020