Hindgut neuroendocrine neoplasms - characteristics and prognosis

The aim of the study was to analyze the clinicopathologic characteristics and prognostic factors of hindgut-rectal neuroendocrine neoplasms.

The study included 38 patients with rectal neuroendocrine tumors who were treated at the Department of Endocrinology, Metabolism and Internal Diseases, Poznan University of Medical Sciences, Poznan, Poland from February 2010 to December 2015. The clinicopathological data were retrospectively reviewed, extracted, analyzed, and patients were followed up to determine their survival status. Follow-up data were available for all 38 patients. Uni- and multivariate Cox regression analyses were performed to determine the prognostic factors significantly associated with overall survival.

The tumors occurred mostly in the middle and lower rectum, and the most typical symptoms experienced by patients were hematochezia and diarrhea. The median distance between the tumors and the anal edges was 4.7 ±1.3 cm, and the median diameter of the tumors was 0.9 ±1.2 cm. The major pathological types were neuroendocrine neoplasm G1 in 31 patients, and neuroendocrine neoplasm G2 in 7 patients. Tumor-node-metastasis (TNM) stages I, II, III and IV tumors accounted for 76.3% (29/38), 5.3% (2/38), 7.9% (3/38) and 10.5% (4/38) of patients, respectively. The main treatment method was transanal extended excision or endoscopic resection. The 1-, 3- and 5-year survival rates of the whole group of patients were 100%, 83.7%, and 75.3%, respectively.

Univariate analysis showed that age (p = 0.022), tumor diameter (p < 0.001), histological type (p < 0.001), and TNM stage (p < 0.001) were all prognostic factors.