Endoscopic full-thickness resection of T1 colorectal cancers: a retrospective analysis from a multicenter Dutch eFTR registry.

Background and study aims: Complete endoscopic resection and accurate histological evaluation for T1 colorectal cancer (CRC) is critical to determine subsequent treatment. Endoscopic Full-Thickness Resection (eFTR) is a new treatment option for T1 CRC <2cm. We aim to report clinical outcomes and short-term results. Patients and methods: Consecutive eFTR procedures for T1 CRC, prospectively recorded in our national registry between November 2015 and April 2020, were retrospectively analysed. Primary outcomes were technical success and R0 resection. Secondary outcomes were histological risk-assessment, curative resections, adverse events and short-term outcomes. Results: We included 330 procedures: 132 primary resections and 198 secondary scar resections after incomplete T1 CRC resection. Overall technical success, R0 resection and curative resection rates were 87.0% (95% CI [82.7 – 90.3%]), 85.6% (95% CI [81.2 – 89.2%]) and 60.3% (95% CI [54.7 – 65.7%]). Curative resection rate for primary resected T1 CRC was 23.7% (95% CI [15.9 – 33.6%]) and 60.8% (95% CI [50.4 – 70.4%]) after excluding deep submucosal invasion as risk-factor. Risk-stratification was possible in 99.3%. Severe adverse event rates was 2.2%. Additional oncologic surgery was performed in 49/320 (15.3%), with residual cancer in 11/49 (22.4%). Endoscopic follow-up was available in 200/242 (82.6%), with a median of 4 months and residual cancer in 1 (0.5%) following an incomplete resection. Conclusions: eFTR is a relatively safe and effective method to resect small T1 CRC, both as primary and secondary treatment. eFTR can expand endoscopic treatment options for T1 CRC and could help to reduce surgical overtreatment. Future studies should focus on long-term outcomes.