Preoperative chemoradiotherapy (QT-RT) with capecitabine and oxaliplatin (CAPOX) in patients with locally advanced rectal cancer.

Abstract

e14628 Background: Locally advanced rectal carcinoma is associated with high rate of abdomino-perineal amputation. We analyzed a cohort of patients (pts) diagnosed of locally advanced rectal cancer, treated with neoadjuvant QT-RT with CAPOX followed by four cycles of adjuvant CAPOX after surgery. Methods: Pts with locally advanced rectal cancer (T3-T4 and/or N+) were treated with oxaliplatin (50mg/m2 day 1, 8, 22 and 29) and capecitabine (1650mg/m2 on days 1 to 14 and 22 to 35) combined with pelvic radiotherapy (180cGy/day; 45Gy in 25 fractions). Surgery was scheduled 4 to 6 weeks after completion QT-RT. Four cycles of adjuvant XELOX were administered (capecitabine 2000mg/m2 on days 1 to 14) and oxaliplatin (130mg/m2 day 1) every 3 weeks. The main end points assessed were: rate of sphincter preservation, pathological complete response (pCR) rate, toxicity and feasibility of postoperative chemotherapy. Local staging was done with pelvic MRI and/or EUS. Results: From Sept 2005 to Nov 2012, 201 pts with locally advanced rectal cancer were included. Pts characteristics: M/F 135/66; ECOG 0/1/2: 48/149/4; median age 65 (28-81); upper/mid/distal rectum 29/105/67; stage cT3/N- 21, cT2-T3/N+ 140, cT4/N- 6, cT4/N+ 34. Full dose preoperative QT-RT was administered in 192 (95%). The main toxicities were diarrhea grade 2/3: 42/24 and neurotoxicity grade 1/2: 94/7. After treatment 198 pts underwent surgery. Sphincter preservation and R0 resections were achieved in 125 and 184 respectively. pCR was achieved in 35 pts (17.4%). 145 pts (72%) received all 4 cycles of adjuvant XELOX. Grade 3/4 toxicities included vomiting 3/0, diarrhea 7/0, skin-foot syndrome 2/0, mucositis 1/0, neurotoxicity 6/0, neutropenia 10/1 and thromopenia 6/1. Downstaging in T/N was achieved in 108/144 pts (53.7/71.6%) respectively. 3-year progression-free and overall survival were 75% and 83% respectively. No toxic deaths were reported. Conclusions: Combination QT-RT based in capecitabine and oxaliplatin is a well tolerated regimen and achieved encouring rates of pCR, R0 resection, sphincter preservation and tumor downstaging in patients with locally advanced rectal cancer.