Surgical treatment of carcinoid tumors of the small bowel, appendix, colon and rectum.

Carcinoid tumors occur most frequently in the gastrointestinal tract. Most of these tumors are clinically silent and the diagnosis is not made before surgery. The surgical treatment depends on the localization and the size of the tumor. Small bowel carcinoid tumors metastasize in 20-30% of the cases if the tumor is smaller than 1 cm. Therefore, the primary tumor should always be resected widely including the regional lymph nodes. Carcinoid tumors of the appendix less than 1 cm in size do not metastasize. For such patients an appendectomy is the treatment of choice. For tumors larger than 2 cm, a right hemicolectomy should be performed. If the tumor is between 1 and 2 cm, the surgical treatment depends on several factors (positive lymph nodes, extension of the tumor into the mesoappendix or subserosal lymphatic invasion, age of the patient). In young patients, an aggressive treatment is preferred. Carcinoid tumors of the colon and rectum less than 2 cm in size rarely metastasize. The surgical treatment for patients with tumors less than 2 cm is local excision, whereas for patients with tumors larger than 2 cm a wide resection is advocated.