Long-Term Outcomes of Colorectal Endoscopic Submucosal Dissection: Recurrence and Metachronous Cancer

Endoscopic submucosal dissection (ESD) is widely used to treat colorectal tumors, and long-term outcomes after ESD have increasingly been reported. Post-treatment endoscopic surveillance is essential for detecting local recurrence and metachronous cancer. However, although the incidence of metachronous cancer after ESD has been reported, the detailed clinicopathological characteristics remain unclear. To determine the incidence and clinicopathological characteristics of metachronous cancer, we evaluated long-term outcomes after colorectal ESD.

This retrospective study analyzed data on clinicopathological characteristics, procedural details, adverse events, and long-term outcomes for 486 patients (577 lesions) who underwent colorectal ESD between November 2005 and April 2017. Rates of local recurrence and metachronous cancer, and the clinicopathological characteristics of metachronous cancer, were investigated.

The en bloc resection rate was 96.1%, and the curative resection rate was 93.5%. Delayed major bleeding occurred in 10 patients (1.7%). Additional colectomy with lymph node dissection was performed in 22 patients (3.3%). Local residual carcinoma was identified in four patients, and lymph node metastasis was observed in one patient with poorly differentiated adenocarcinoma. One patient with deep submucosal invasion and vascular invasion developed lung metastasis 31 months after ESD despite the absence of local residual carcinoma and lymph node metastasis. In addition, a patient with a rare 6-mm rectal neuroendocrine tumor developed liver metastasis 17 months after ESD. Local recurrence was observed in two lesions (0.4%) within 1 year after ESD, and both lesions were successfully treated by endoscopic resection. No recurrence was observed after complete and curative resection. During surveillance colonoscopy, 11 cases of metachronous cancer were detected. All were non-polypoid lesions and more than half were located in the right colon.

As was noted in previous studies, ESD for colorectal tumors yielded a high en bloc resection rate and favorable long-term outcomes, with a low incidence of local recurrence. Early surveillance colonoscopy is recommended after histologically incomplete resection to detect local recurrence. Long-term surveillance colonoscopy should focus on detecting metachronous cancer, particularly slightly elevated (type 0-IIa) lesions.