Clinical outcomes of deep invasive submucosal colorectal cancer after ESD

Background and study aims Endoscopic submucosal dissection (ESD) is a reliable method that can replace surgery under certain conditions. However, limited information is available on the clinical course of T1b colorectal cancer (CRC) after ESD. The aim of the study was to clarify the feasibility of ESD for T1b CRC. Patients and methods Three hundred and two patients with 312 T1 CRC were identified in this retrospective cohort study. All patients were treated with ESD, other endoscopic treatments, or surgery. In this study, we (I) investigated the en bloc resection rate of ESD and (II) compared the overall survival (OS) rate for patients who underwent ESD with additional surgery (Group A) and surgery without upfront endoscopic resection (Group B) for T1b CRC. Results No significant differences were observed in the en bloc resection rates between T1b and T1a CRC (100 vs. 98.7%), but the en bloc R0 resection rate was significantly lower in T1b CRC than in T1a CRC (64.7 vs. 97.4%). Regarding complications, perforations occurred in 2.9% of patients with T1b CRC, which was not significantly different from the rate of 5.3% in patients with T1a CRC. No significant differences were observed in the OS or recurrence-free survival (RFS) curves between Groups A and B (OS rates at 5 years: 92.3 vs. 88.9%, RFS rates at 5 years: 81.4 vs. 85.3%). Similarly, the 5-year disease-specific survival (DSS) rate of Group A was identical to that of Group B (both 100%). Conclusions ESD for T1b CRC before surgery is a possible strategy because of the low rate of complications and favorable long-term outcomes.