Session Item

Radiotherapy (RT) is already performed to treat primary brain tumors; however, the effect of repeated RT for recurrent tumors has not been fully explored. The aim of this study is to determine the efficacy of re-irradiation in recurrent glioblastoma.

Between November 2019 and September 2021, 30 patients affected by recurrence of high grade glioma were evaluated and treated with re-RT. Stereotactic radiosurgery (SRS) and hypo-fractionated stereotactic radiotherapy (HSRT) were performed using Volumetric Modulated Arc Technique (VMAT).

At diagnosis, the median age was 54 years (range 36-76) and median KPS was 80% (range 50-90%). All patients underwent to surgical procedures. Twenty-one patients (70%) had RPA class ≤ IV. Histological diagnosis in one case was oligodendroglioma, 24 patients (80%) were affected by glioblastoma, including 3 cases of multifocal form, and 5 (17%) by anaplastic astrocytoma. In 40% of cases, MGMT was unmethylated and, in 80% of cases, IDH was wild type.

All patients underwent to adjuvant RT with concomitant TMZ, with different fractionation approaches: 9 (30%) received hypofractionated RT and 21 (70%) received conventional fractionated RT. The median time occurred between surgical procedure and RT was 8 weeks (range 2-18). The median time occurred between adjuvant RT and disease recurrence was 8 months (range 2-27).

At the time of disease recurrence, all patients underwent to re-irradiation receiving SRS-HSRT with a median dose of 24 Gy (range 18-36 Gy) and median fractions of 5 (range 1-6).

At a median follow-up time from recurrence of 13 months (range 3-56 months), 10 patients (33%) were alive: 2 (20%) with partial response disease, 7 (70%) with stable disease and 1 (10%) with progression disease out-field.

During follow-up, 9 patients with out-field progression disease and good performance status underwent to third re-irradiation, with a median dose of 21 Gy (range 14-27 Gy) and median fractions of 3 (range 1-5).

No acute or late neurological side effect grade ≥ 2 were reported. No case of radio-necrosis was detected. In all cases, prophylactic steroid therapy was administrated. One patient experienced, after second surgery and during Regorafenib, dehiscence of the surgical wound. In 3 cases, Grade 2 distal paresthesia was reported. Grade 3-4 hematologic toxicity occurred in 7 cases. Three case of Grade 5 toxicities were reported: 2 septic events and 1 thrombo-embolic event.

The median OS after recurrence was 9.8 months (95%CI 7.06-12.13) and 1-year OS was 29% (95%CI 11.4-49.2%).

No relevant clinical deteriorations in term of performance status were described.

Re-irradiation for patients affected by recurrent glioblastomas should be considered for its safety and feasibility. In this setting of patients with a poor prognosis, a gain, even if modest, in term of OS, without affecting the patient's quality of life, it could be favourable. An evaluation in a larger number of patients is needed to obtain more solid data.