614P - Neoadjuvant Treatment in Rectal Cancer: Long- VS Short-Course Radiotherapy

Abstract

ABSTRACT Introduction Two schemes for pre-operative radiotherapy (RT) in locally advanced rectal carcinoma (RC) are possible: long-course irradiation (45 – 50.4 Gy / 25 – 28 fr) with chemotherapy (CHT), followed by surgery after 6 to 8 weeks; and short-course irradiation (25 Gy / 5 fr), followed by surgery usually 1 week after. Some studies have shown a downstaging effect with delayed surgery in short-course irradiation Goal: Compare results of different irradiation schemes for neoadjuvant treatment of RC in a Radiation Oncology Department. Methods Patients with RC treated pre-operatively between 2002 and 2012 were included. RT was performed according to 2 schemes: long-course scheme (GROUP 1) using only RT (GROUP 1A), with oral CHT (GROUP 1B) or infusion CHT (GROUP 1C); and short-course scheme (GROUP 2). Results 265 patients were included, 227 in GROUP 1. GROUP 1A were older than GROUP 1B and 1C (p 1 week) there were significant differences in locoregional response (28.6% vs 75.0%, p = 0.033), with 2 complete responses in those with greater time to surgery. Conclusions These results are according to literature: long-course scheme with concomitant CHT provided better locoregional response, although with some acute toxicity; a higher time to surgery in short-course scheme appears to have better results, with no increase in surgical complications. Short-course irradiation with surgery delay appears to be a useful alternative to long-course radiochemotherapy, namely in patients with advanced age and associated comorbidities. Disclosure All authors have declared no conflicts of interest.