P3-065 - Safety and Efficacy of Proton-Beam Radiation Therapy for Patients with Locally Recurrent rectal Cancer

Abstract

ABSTRACT Background Radical surgical resection is considered as a standard therapy for locally recurrent rectal cancer (LRRC). Surgical procedures for LRRC, such as total pelvic exenteration, are highly invasive; however, the rate of curative resection is modest. As for definitive radiotherapy, it is often difficult to deliver a curative dose because local recurrences occur adjacent to radiosensitive areas such as the gastrointestinal tract. Proton-beam therapy involving intense and highly focused irradiation can effectively treat local recurrences while avoiding damage to the surrounding organ. Therefore, we investigated this therapy as a treatment option for LRCC patients who had unresectable LRCCs or had refused surgery. Objects We retrospectively reviewed 13 consecutive LRCC patients who (i) had unresectable LRCCs or had refused surgery, (ii) had received proton-beam radiation therapy at Shizuoka Cancer Center during November 2005–January 2011, and (iii) had not undergone pelvic irradiation earlier. The clinical course of all the patients was examined after the therapy. Methods All the patients had received a total dose of 70 GyE proton-beam irradiation (in 25 fractions) and were followed up to disease progression. Results The patient characteristics were as follows: median age, 58 years (range, 37 ∼ 82 years); men/women, 7/6; PS, 0/1, 10/3; recurrence site, anterior/Post-erior/lateral/anastomosis, 0/6/7/0; previous chemotherapy regimen number, 0/1/2/ > 3, 5/2/4/2; and histological types, tub1/tub2/por/unknown, 3/7/1/2.At a median follow-up time of 1264 days (range, 467–2105 days), the local control rate, median local control time, and median progression-free survival were 46%, 504 days (range, 128–2105 days), and 414 days (range, 58–2105 days), respectively. Grade 3/4 toxicity was observed in 1 patient with urinary tract obstruction; there were no treatment-related deaths. Conclusions Proton-beam radiation therapy was well tolerated for LRCC patients who had unresectable LRCCs or had refused surgery, and controlled LRRC in approximately 50% of the patients. Therefore, this therapy might be considered a treatment option for LRRC.