First toxicity and efficacy analysis of a phase II trial of a novel 5-FU-oxaliplatin based chemoradiation schema for stage II and III rectal carcinoma

Abstract

14591 Background: 5-FU based neoadjuvant chemoradiation (CRT) has become the standard of care for stage 2 and 3 rectal cancer (ca). Pathologic complete responses (pCR) and downstaging have been associated with improved survival outcomes. The addition of oxaliplatin or irinotecan to neoadjuvant treatment has led to improved pCR and downstaging. The feasibility and efficacy of “total” oxaliplatin therapy (pre and postoperative oxaliplatin) for stage 2 and 3 rectal ca patients has yet to be defined. Objective: To determine the feasibility, toxicity and efficacy of neoadjuvant oxaliplatin, 5-FU and RT followed by surgery, with postop adjuvant modified FOLFOX6. Methods: Single institution, single arm phase II trial of oxaliplatin 60mg/m2 weekly for 6 weeks with continuous infusion 5- FU 225 mg/m2/excision. Postoperative therapy consisted of mFOLFOX6 every 2 weeks for 6 cycles. Eligibility included previously untreated, histologically proven rectal cancer, T3–4N0M0 or TanyN+M0 (stage II-III). Results: 15 pts have been enrolled in this study. One died of disease prior to CRT. Eight pts have completed total oxaliplatin therapy. One pt had 1 cycle deleted due to grade 2 neuropathy. Prior to adjuvant therapy 2 pts dropped out: 1 from pulmonary symptoms and one asthenia. Two pts attained a pCR and 6 attained downstaging. Significant toxicity has been limited to grade 3 neuropathy in one pt (completely resolved) and one grade 3 GI toxicity (self limited). Conclusions: Early analysis shows the feasibility of pre and post operative oxaliplatin based therapy. The limited data permit only observation of pCR and tumor downstaging rates but toxicity outcomes are encouraging. Further accrual and follow-up will better define efficacy and toxicity of this regimen. [Table: see text]