(P039) Reirradiation for Recurrent Gliomas: The University of Miami Experience

Dayssy A. Diaz, MD, Steven Engel, BS, Arnold Markoe, MD, MSC, Joseph E. Panoff, MD, Fazillat Ishkanian, MD, PhD; University of Miami/Jackson Memorial Hospital

Purpose: Treatment options for recurrent gliomas include surgery, chemotherapy, and radiotherapy. The majority of patients receive radiotherapy as part of their primary treatment, and multiple reirradiation fractionation schedules have been used in an attempt to decrease toxicity. We sought to report our institutional experience with reirradiation in the management of recurrent gliomas.

Methods: A retrospective review was performed of adult patients with recurrent gliomas who received reirradiation between 2000 and 2013 with at least partial overlap of the initial radiation fields. Progression-free survival (PFS), overall survival (OS), and toxicity were evaluated. Hyperfractionated radiotherapy (HFR) was delivered at 1.2-Gy fractions bid. Standard radiotherapy (SRT) was delivered at 1.8–2.15 Gy once daily. Hypofractionated radiotherapy (HOR) was delivered at daily doses of 2.5 Gy or larger. Stereotactic radiosurgery (SRS) was delivered in a single fraction. Comparisons among fractionation schedules were performed.

Results: A total of 27 patients met our inclusion criteria. The mean age at initial diagnosis was 45 years (range: 20–81 yr), 59.3% were male, and all patients underwent at least subtotal resection (STR) at the time of initial diagnosis. The mean total radiotherapy dose at initial treatment was 58.5 Gy, and median dose was 60 Gy (range: 32–60 Gy). Concurrent chemotherapy (temozolomide) with initial radiotherapy was given in 70.8% of patients. World Health Organization (WHO) grade 4 glioma was diagnosed in 59.3% of patients at the time of recurrence.

The percentages of patients who received HFR, SRT, SRS, and HOR were 51.9%, 22.2%, 14.8%, and 11.1%, respectively. The dose range (median) was 39.2–60 Gy (39.6 Gy), 30–60.2 Gy (56.65 Gy), 18–21 Gy (19 Gy), and 25–30 Gy (25 Gy) for HFR, SRT, SRS, and HOR, respectively. For the purpose of this analysis, HOR and SRS outcomes were reported as a group, referred to as hypofractionated (HPR). There was no difference on initial grade (P = .35), grade at recurrence (P = .863), age (P = .486), sex (P = 1.00), or type of surgery between groups (P = .877). Two patients in the HPR group received a third course of radiotherapy, with one patient receiving HFR to a total dose of 39.6 Gy and the other one receiving SRS with 21 Gy.

Three cases of radiation necrosis were reported: two of them in patients who received HPR (one after a third radiotherapy course with HFR) and one case in the HFR group. Chemotherapy was received by 74.1% of patients as part of their salvage treatment. The median PFS and OS after reirradiation were 2.03 and 6.8 months, 3.8 and 10 months; and 5.1 and 8.1 months for the HFR, SRT, and HPR patients, respectively. There was no difference in OS (P = .58) or PFS (P = .23) among groups.

Conclusions: Reirradiation is safe and feasible for the treatment of recurrent gliomas. Radiation necrosis was observed infrequently and occurred after HPR or HFR. No significant difference between fractionation groups was found in this cohort. Given the shorter treatment time, hypofractionation or SRS may be preferable for reirradiation of recurrent gliomas. SRT is a reasonable alternative in patients with large-volume disease or significant overlap of radiation fields.