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

We aimed to clarify the long-term outcomes of patients with T1 colorectal carcinoma (CRC) after endoscopic resection (ER) and surgical resection. 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. 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 < 0.01), and 5-year disease-free survival (DFS) rates were 98.1, 97.9, and 98.5%, respectively. Thirty-two patients experienced local recurrence or distant/lymph node metastasis (Group A: 6; Group B: 13; Group C: 13) and 14 patients died of primary CRC (Group A: 3; Group B: 7; Group C: 4). Age >= 65 years, protruded gross type, positive lymphatic invasion, and high budding grade were significant predictors of recurrence in non-endoscopically curable patients. Our findings supported the JSCCR criteria for endoscopically curable T1 CRC. ER for T1 CRC did not worsen the clinical outcomes of patients who required additional surgical resection.