Long-term outcomes after treatment for T1 colorectal carcinoma: a multicenter retrospective cohort study of Hiroshima GI Endoscopy Research Group

Background We aimed to clarify the long-term outcomes of patients with T1 colorectal carcinoma (CRC) after endoscopic resection (ER) and surgical resection. Methods We examined T1 CRC patients treated during 1992–2008 and who had ≥5 years of follow-up. Patients who did not meet the curative criteria after ER according to the Japanese Society for Cancer of the Colon and Rectum (JSCCR) guidelines were defined as “non-endoscopically curable” and classified into three groups: ER alone (Group A: 121 patients), additional surgery after ER (Group B: 238 patients), and surgical resection alone (Group C: 342 patients). Long-term outcomes and predictors of recurrence were analyzed. Results Of the 882 patients with T1 CRC, 701 were non-endoscopically curable. Among these patients, recurrence and 5-year overall survival (OS) rates were 0.6 and 91.1%, respectively. In Groups A, B, and C, recurrence rates were 5.0, 5.5, and 3.8%, OS rates were 79.3, 92.4, and 91.5% ( p