Rectal carcinoids are becoming more common: in the USA they have increased in frequency by 800 - 1000 % in the past 35 years. This dramatic increase is probably related to the introduction of colonoscopic screening which also results in the "incidentally" detected neuroendocrine rectal tumours/carcinomas being smaller than in the pre-screening era. Endosonography is the method of choice for determining the size and depth of penetration of the tumours and for detecting lymph node metastases. Tumours of < 10 mm in size that have not infiltrated the muscularis propria can usually be removed endoscopically. When invasion of lymph or blood vessels or lymph node metastases are found, surgical resection of the lymph nodes is indicated. Neuroendocrine rectal neoplasms (rectal carcinoids) of 10.1 - 20 mm in diameter have a metastasis risk of 17 - 42 (81) % for neuroendocrine rectal neoplasms > 20 mm in size this risk increases to 60 - 80 %. A carcinoid syndrome is rarely observed, even in cases of distant metastases of neuroendocrine rectal carcinomas. Stable somatostatin analogues and interferon-alpha constitute the drug therapies of choice for carcinoid syndrome. As a result of the increasing early detection of rectal carcinoids/carcinomas the prognosis for the patients has improved considerably in the last 30 years. In addition to the early detection of colorectal adenoma and adenocarcinoma, screening colonoscopy also makes possible the early detection and early therapy for neuroendocrine rectal tumours/carcinomas.
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