Efficacy endpoints of RTOG 0247: A randomized phase II study of neoadjuvant capecitabine (C) and irinotecan (I) or C and oxaliplatin (O) with concurrent radiation therapy (RT) for locally advanced rectal cancer.

Abstract

3517 Background: The primary endpoint analysis of RTOG 0247 showed that preoperative pelvic RT plus C + O achieved a pathologic complete response rate (pCR) pre-specified threshold (21%) to merit further study, whereas the RT+ C + I arm did not (10%) (ASCO 2008). This current analysis reports on the secondary efficacy endpoints. Methods: A randomized phase II trial evaluated preoperative RT (50.4 Gy in 1.8 Gy fractions) with (1) concurrent C (1,200 mg/m2/d orally M-F during RT) and I (50 mg/m2 IV weekly x 4 doses) (Arm 1), and with (2) concurrent C (1,650 mg/m2/d orally M-F during RT) and O (50 mg/m2 IV weekly x 5 doses) (Arm 2) in patients with clinical stage T3 or T4 rectal cancer ² 12 cm from the anal verge. Surgery was performed 4-8 weeks following completion of chemoradiation. Four to 6 weeks after surgery, adjuvant chemotherapy (O 85 mg/m2; leucovorin 400 mg/m2 IV over 2 hours; 5FU 400 mg/m2 IV bolus; 5FU 2400 mg/m2/46 hr infusion) was administered every 2 weeks x 9 cycles. Disease-free (DFS) and ov...