Recurrence and Survival of Neuroendocrine Neoplasms of the Rectum: Single-Center Experience

Background In 2010, the World Health Organization proposed that rectal neuroendocrine neoplasms (NENs) be considered malignant. We hypothesized that patients with small, low-grade, locally excised tumors have a low risk of recurrence and death. Methods Retrospective review of institutional database 2006-2017 including consecutive adults with newly diagnosed rectum NENs. Outcome measures included risk of recurrence and 5-year overall survival. Results A total of 122 patients were diagnosed with rectal NENs. Most patients were asymptomatic and diagnosed during screening colonoscopy (80, 66.1%), had small tumors (median 0.6 cm, IQR 0.5-1) with intact muscularis propria on EUS (62/65, 95.4%), and were low grade (2017 WHO grades 1-2, n = 116, 95.1%). Lymph node and distant metastasis were found in 4 (3.3%) and 4 (3.3%) of patients, respectively. Patients were treated with local excision in 93.4% of cases with polypectomy (52, 42.6%), endoscopic mucosal resection (48, 39.3%), and transanal excision (14, 11.5%). Three patients (2.5%) required abdominoperineal resection or low anterior resection, and five patients (4.1%) received adjuvant chemotherapy. Of 87 patients surveilled, 4 (4.6%) recurred at a median time of 1 year (IQR 0.6-8). Death from neuroendocrine neoplasms occurred in 5 (4.1%) patients, all with lymph node (1/4) or metastatic disease (4/5) on presentation. Median time to death from NEN was 0.8 years (0.7-2.4). Overall 5-year survival for patients with localized disease was 98.2% (95% CI 93-99.5, Fig. 1). Conclusion Patients with small, low grade rectal NENs treated with local excision have excellent oncologic outcomes.