O’Dwyer, P. J.

3526 Background: In the US pts with stage II/III rectal cancer routinely receive pre or postoperative RT/FU. To date, in addition to chemoradiation, standard adjuvant chemotherapy has been limited to single agent FU. Improved survival with irinotecan and oxaliplatin in pts with metastatic colorectal cancer led to exploration of combination chemotherapy in the adjuvant setting in pts with rectal cancer. Methods: Pts on E3201 (T3–4 Nany M0, T1- 2 N + M0) had the option to receive FU with either pre- or postoperative RT (50.4 Gy). Pts were randomized to postoperative chemotherapy: FU (500mg/m2) + LV (500mg/m2) weekly x 6/8 wks x 3 cycles or irinotecan (FOLFIRI) (180mg/m2) vs oxaliplatin (FOLFOX) (85mg/m2) both administered with LV (400 mg/m2) FU (400mg/m2 bolus) + continuous FU (2.4 gm/m2/46 hours) q 2 wks x 8 cycles. Results: 225 pts of 3150 planned were recruited. 178 pts were randomized and 126 pts submitted treatment completion forms (accrual period 10/03–4/05). The Data Monitoring Committee closed E3201 when the GI Intergroup developed an alternative trial with bevacizumab (E5204). Toxicity information is reported for 93% of pts (165/178) ( Table ). There were no significant differences in toxicity between those pts treated with pre- vs postoperative RT/FU, although, for the subset of pts who received adjuvant FOLFIRI after postoperative RT/FU, there was a trend towards more diarrhea. Conclusion: FOLFOX as rectal adjuvant therapy is a common platform for new clinical trials, although there have been limited toxicity data reported. E3201 provides important comparative toxicity information demonstrating that FOLFOX can be safely administered to rectal cancer pts following chemoradiation. [Table: see text] [Table: see text]