RECTAL NEUROENDOCRINE TUMORS: SHORT-TERM AND LONGTERM RESULTS OF LOCAL EXCISION

Abstract

Objective: Rectal neuroendocrine tumors (NETs) are rare neoplasms and, therefore, few clinical observational studies have been performed and few publications are available on this matter. With regard to the aforesaid, it seems topical to analyze and publish results of local rectal NET excisions that were performed at Federal State Budgetary Institution «State Scientific Centre of Coloproctology n.a. A.N. Ryzhikh» of the Ministry of Healthcare of Russia. Patients and methods: Within the period from December 2011 until June 2018 14 patients, including 4 (28.6%) men and 10 (71.4%) women underwent transanal endoscopic microsurgery (TEM) for rectal NETs at Federal State Budgetary Institution «State Scientific Centre of Coloproctology n.a. A.N. Ryzhikh» of the Ministry of Healthcare of Russia. The mean age of the patients was 53.2 ± 14.14 (24 to 74) years old. Remote results of the treatment performed were traced for all 14 (100%) patients. Kaplan-Meier curves were graphed and then compared using the log-rank (Mantel-Cox) method. Results: On the basis of findings of pathomorphological studies, 10 (71.4%) patients were diagnosed with stage pT1a tumors, 3 (21.4%) participants had stage pT1b tumors, and 1 (7.2%) patient had stage pT2 tumor; 11 (78.6%) patients enrolled to the study had G1 tumors and 3 (21.4%) participants had G2 tumors; and lymphovascular invasion was detected in 4 (28.5%) of the 14 patients. All excisions were radical (R0). The median follow-up period was 25.5 (9 to 86) months. Disease progression was found in 3 (21.4%) of the 14 patients. NET size exceeding 10 mm was the only statistically significant factor that had impact on relapse-free survival (p=0.032). Conclusion: Local excision of rectal NETs can be an option of surgical treatment for small (< 10 mm) low-grade tumors. At the same time, precision and safety are of unquestionable priority in TEM.