Do we need adjuvant therapy in rectal cancer with complete pathologic response (ypT0N0) after induction chemoradiation and laparoscopic mesorectal excision

3536 Background: Neoadjuvant chemo-radiotherapy (CRT) is the standard of care for patients (pts) with u>T3 by endoscopic ultrasound (EUS) rectal cancer. Although pts with complete pathological response (ypT0N0) fare well in multiple series, there is uncertainty of whether it’s due to the induction (CRT), due to the adjuvant chemotherapy (ACT) or due to the combination of both therapies. We have evaluated long-term outcomes in CRT-treated pts. Those with ypT0N0, were not treated with ACT. Methods: Pts with u>T3 rectal cancer, received neoadjuvant chemotherapy (225mg/m2/day 5-fluorouracil (FU)) in continuous infusion (CI) per 5 weeks (wks) and concomitant radiotherapy (45 Gy). Laparoscopic surgery (LAP) was planned after an interval of 5-8 wks. Pts achieving ypT0N0 were no treated with ACT. Pts with ypT>1 or N1 were treated with 3 gr/m2 FU in 48 hour CI and LV 200 mg/m2 every 2 wks x 6 cycles. Results: From November 2000 to November 2008, a cohort of 173 pts were treated with induction CRT and 167 pts under...