1704P - Prospective feasible study to evaluate neoadjuvant-synchronus S-1 + RT for locally advanced rectal cancer: a multicenter phase-II trial (UMIN ID03396)

Date 01 October 2012
Event ESMO Congress 2012
Session Poster presentation III
Topics Anticancer agents
Surgical oncology
Colon and Rectal Cancer
Biological therapy
Radiation oncology
Presenter Masafumi Inomata
Authors M. Inomata
  • Department Of Gastroenterological Surgery, Oita University Faculty of Medicine, 8795593 - Yufu/JP



Fluorouracil-based chemoradiotherapy (CRT) is regarded as a standard perioperative treatment in locally advanced rectal cancer. We investigated the efficacy and safety of substituting fluorouracil with the oral prodrug TS-1.


A multi-institutional (17 specialized centers), interventional phase II trial, was conducted from April 2009 to August 2011.This study is registered with UMIN-CTR, number C003396. For inclusion, patients must fulfill the following requirements before neoadjuvant CRT: (i) histologically proven rectal carcinoma; (ii) tumor located in the rectum (upper,lower); (iii) cancer classified as T3-4, N0–3 and M0; Two cycles of neoadjuvant CRT with TS-1 (100 mg/m2 on days 1-5, 8-12, 22-26, and 29-33) is administered, and irradiation (total 45Gy/25fr, 1.8Gy/day, on days 1-5, 8-12, 15-19, 22-26, and 29-33) is performed. Total mesorectal excision with D3 lymphadenectomy is performed during the 4th and 8th week after the end of the neoadjuvant CRT. The primary end-point is rate of complete treatment of neoadjuvant CRT. Secondary endpoints are response rate of neoadjuvant CRT, short-term clinical outcomes, rate of curative resection, and pathological response (grade2/3).


This trial included 37 patients. A complete treatment of neoadjuvant CRT was found in 83.3% of patients (95%CI;71.2 ∼ 95.5%), and an adverse event (grade 3/4) occurred in 4 patients(11.1%). A rate of an overall downstaging (PR/CR;RECIST 1.0) was 83.3% (95%CI; 71.2 ∼ 95.5%), and a pathologic response rate was 50.0% (95%CI; 33.7 ∼ 66.3%).


Our prospective phase-II study demonstrated that a neoadjuvant-synchronus TS-1 + RT for locally advanced rectal cancer was feasible in terms of pathological response and adverse events.


All authors have declared no conflicts of interest.