The efficacy of endoscopic submucosal dissection for 10-20 mm rectal neuroendocrine tumors based on resection margin status.

backgroundCurrent guidelines recommend that rectal neuroendocrine tumors (NETs) smaller than 10 mm can be treated by endoscopic resection, whereas tumors larger than 20 mm should be treated by surgical resection. However, the optimal treatment of 10-20 mm rectal NETs remains controversial. We aimed to evaluate the efficacy of endoscopic submucosal dissection (ESD) for 10-20 mm rectal NETs based on resection margin status.

methodsWe performed a retrospective review of 190 patients with 10-20 mm rectal NETs who underwent ESD at Zhongshan Hospital, Fudan University. The preoperative baseline information, procedure-related characteristics and postoperative outcomes were analyzed.

resultsThe mean maximal diameter was 11.8 ± 2.5 mm, with 156 lesions at 10-14 mm and 34 lesions at 15-20 mm. The en bloc resection rate and technical success rate were both 100%. The mean procedure duration was 28.54 ± 13.23 min, with 56 (29.5%) procedures lasting > 30 min. There were only 2 cases of fever over 38.5 °C and 2 cases of delayed bleeding. All patients were eventually discharged safely and the mean hospital stay after procedure was 1.68 ± 0.82 days. Tumor grade was G1 in 136 (71.6%) patients and G2 in 54 (28.4%) patients. Positive margins were found in 42 patients, including 6 cases (3.2%) with lateral margin involvement, 35 cases (18.4%) with basal margin involvement and one case with both. The mean follow-up was 48.39 ± 27.12 months, with only 3 recurrences. The recurrence rate in the positive margin group was not higher than that in the negative margin group. Estimated progression-free survival and overall survival were also not significantly different between the two groups.

conclusionsESD is a safe and effective technique for 10-20 mm rectal NETs. With limited follow-up time, there may be no relationship between tumor margin and recurrence.