In general, rectal carcinoids smaller than 1 cm can be safely removed by endoscopic excision. Excised specimens should be examined histologically to exclude muscularis invasion.[2,3,4,5]
Tumors measuring 1 cm to 2 cm should be investigated by transanal endosonography or magnetic resonance imaging. Absence of muscularis invasion or regional metastases may justify local excision. The outcome from treating a lesion between 1 cm and 2 cm is unclear. The metastatic risk is between 10% and 15%. Some studies demonstrate no benefit with aggressive management whereas other studies have reported successful treatment with local or radical surgery.[2,7,8] Although it may be possible to recognize tumors with particular atypia and high mitotic index before embarking on radical surgery, the presence of muscularis invasion or regional metastases generally supports aggressive excision. Generally, the procedure is an anterior rectal resection with total mesorectal excision and regional lymphadenectomy. In patients with distant metastases, prognosis is generally poor with an overall 5-year survival rate of approximately 30%.
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A similar approach to that used for tumors measuring 1 cm to 2 cm is used in patients with tumors larger than 2 cm but with no metastasis. However, rectal carcinoids of 1 cm to 2 cm have a substantially higher metastatic risk, between 60% and 80%.[2,6,9,10] Invasion of the muscularis propria is common in these tumors and indicates a high metastatic potential. Local resection is unlikely to benefit patient survival with metastatic disease, but it may provide local symptomatic relief. Locoregional resection may control local symptoms and pelvic disease without improving survival.[13,14] Although studies are limited, and the numbers of tumors studied are consistently small, aggressive surgery has not been shown to improve the survival outcome in this group of patients.
Current Clinical Trials
Check for U.S. clinical trials from NCI's list of cancer clinical trials that are now accepting patients with localized gastrointestinal carcinoid tumor and regional gastrointestinal carcinoid tumor. The list of clinical trials can be further narrowed by location, drug, intervention, and other criteria.
General information about clinical trials is also available from the NCI Web site.
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