Long-term clinical outcomes of endoscopic submucosal dissection in rectal neuroendocrine tumors based on resection margin status: a real-world study

Background Endoscopic submucosal dissection (ESD) has been widely adopted in treating rectal neuroendocrine tumors (NETs). However, clinical outcomes in rectal NETs after ESD with different resection margin status remain scanty, particularly in patients with positive resection margins. This study aimed to evaluate the long-term clinical outcomes of ESD in rectal NET based on the resection margin status. Methods This retrospective study included 436 patients diagnosed with rectal NET who had undergone ESD. Clinical data, including age, sex, tumor size, stage, invasion, and the resection margin status, were collected. Further, the patients were assessed for complications, recurrence, distant metastasis, and long-term outcomes. Results Among all 436 patients, 395 patients had their primary ESD in our hospital. Complete resection was achieved in 319 patients. Patients who did not achieve complete resection opted for follow-up (n = 73), salvage surgery (n = 1) and salvage ESD (n = 2). Another 41 had their primary ESD in other hospital with incomplete resection and had salvage ESD in our hospital. All 436 patients had a median follow-up period of 61.4 months (range 33.4-125.3 months). During the follow-up period, two patients developed recurrences, while three patients developed metastasis. There were no significant differences in the 5-year progression-free survival and overall survival between patients with incomplete resection opting for follow-up compared to the other two groups (P = 0.5/0.8). However, the complication rates were significantly higher in patients who received salvage ESD. Conclusion This study demonstrated that positive resection margins have no influence on survival in patients with rectal NET treated using ESD.