Abstract
AIMS
In this report, we describe our experience in dealing with recurrent GBMs in terms of efficacy and toxicity of second RT course (re-RT) with 3DCTR or VMAT protocols. We carefully reviewed our patient’s outcomes and additionally performed a comprehensive and updated meta-analysis of recent recurrent re-RT GBMs literature to compare our results with the ongoing findings of the t studies.
METHODS
We retrospectively collected data between 2017 and 2020 at our Institution. Also, we used the random-effects model to pool outcomes across studies about re-RT GBMs from the recent literature (prospective studies from 2010 to 2020, ≥ 30 patients, re-RT with 3DCTR or IMRT-VMAT) to have a more homogenous cohort in terms of treatment modalities, thus reducing the selection bias.
RESULTS
Re-irradiation was performed at a median interval time of 13.5 (range 4 - 192 months) months from the first RT. The median re-RT dose was 18 Gy (range 12–36 Gy), and the median fraction size was 3,45 Gy (range 1,8–6 Gy). The total median equivalent dose (EQD2) was 84 Gy (range 65.7 – 110 Gy). Our cohort median PFS is 12.5 months (range 4 – 192 months), while the median OS was 26 months (range 6 – 213 months). Our results show that OS-6 and OS-12, from time of re-irradiation, to be 69.2% and 30.7% respectively and the PFS-6 and PFS-12 to be 76.9% and 23.0%, respectively. None of our patients experienced acute toxicity. In our literature research, we found 22 eligible studies, including 1065 patients. The results of the pooled outcomes were: OS-12 rate 35% (95% CI: 30–40%), PFS-12 rate 16% (95% CI 13–19%), and Grade 3 + AE rate < 5% (95% CI 0–10%).
CONCLUSIONS
Our data confirm re-RT is safe and feasible treatment with a limited toxicity for salvage treatment in recurrent GBMs.