Rectal and anal canal neuroendocrine tumours

Neuroendocrine tumors (NETs) are rare, representing 0.5% of all newly diagnosed malignancies. Rectal and anal canal (AC) NETs account for less than 1% of all rectal and AC cancers. Review our institutional experience on NET of the rectum and AC, with emphasis on demographic, histological and treatment features and oncologic outcomes. The study group was identified from the Portuguese Regional South Oncological Registry. From 2000 to 2014, 22 patients with rectal or AC NETs were treated at our institution. Medical records were retrospectively reviewed. There were 12 males (54.5%) and 10 females (45.5%) and the median age at diagnosis was 59.5 years. The majority had rectal NET (81.8%). All 4 patients with AC NETs had neuroendocrine carcinoid (NEC) tumors. Of the patients with rectal NETs, 3 had NEC and 15 had NET, mainly G1. Different approaches to treatment were made according to histological and staging features. After an average follow-up of 39.1 months, 16 patients were alive and only one with evidence of disease. The median time to progression was 12.4 months and the liver was the most frequent site of metastasis. The European and North American Neuroendocrine Societies offer guidelines for the treatment of rectal NETs. However, for AC NETs there are only small series and not prospective studies due to their rarity, hence the importance to report institutional experience. Our practice demonstrated that primary excisional treatment, regardless the histology, provides a favorable prognosis and long survival.