Hyperfractionated accelerated reirradiation for rectal cancer: An analysis of outcomes and toxicity

Background and purpose To evaluate outcomes and toxicity in patients treated with hyperfractionated pelvic reirradiation for recurrent rectal cancer. Materials and methods 102 patients with recurrent rectal adenocarcinoma were treated with pelvic reirradiation with a hyperfractionated accelerated approach, consisting of 1.5 Gy twice daily fractions to a total dose of 30–45 Gy (median 39 Gy), with the most common total dose 39 Gy (n = 90, 88%). The median dose of prior pelvic radiation therapy (RT) was 50.4 Gy (range: 25–63 Gy). Results The median follow-up was 40 months for living patients (range, 3–150 months). The 3-year freedom from local progression (FFLP) rate was 40% and the 3-year overall survival (OS) rate was 39%. Treatment with surgery was significantly associated with improved FFLP and OS, with 3-year FFLP rate of 49% vs. 30% (P = 0.013), and 3-year OS rate of 62% vs. 20% (P < 0.0001), compared to those without surgery. The actuarial 3-year rate of grade 3–4 late toxicity was 34%; patients who underwent surgery had a significantly higher rate of grade 3–4 late toxicity compared to those without surgery (54% vs. 16%, P = 0.001). Conclusions This large, retrospective, single-institution study shows that hyperfractionated accelerated reirradiation was well tolerated. The rate of FFLP was promising, given that the study comprised heavily pre-treated patients with recurrences. Rates of FFLP and OS were particularly impressive in patients who underwent both reirradiation and surgery.