Table 4. Common Genetic Syndromes Associated With Hamartomatous Polyps continued...
Diagnostic studies that may be of value include examination of the stool for blood, studies of liver and kidney function, measurement of carcinoembryonic antigen, and various medical imaging studies, including direct examination using colonoscopy to detect polyps in the large bowel. Other conventional radiographic studies include barium enema or video-capsule endoscopy followed by computed tomography of the chest and bone scans.[83,86,97]
Most patients present with evidence of metastatic disease, either as gross tumor or as microscopic deposits in lymph nodes, on the surface of the bowel, or on intra-abdominal organs.[75,77] Complete surgical excision is the most important prognostic factor and should be the primary aim of the surgeon, but in most instances this is impossible; removal of large portions of tumor provides little benefit for the individuals with extensive metastatic disease. Most patients with microscopic metastatic disease generally develop gross metastatic disease, and few individuals with metastatic disease at diagnosis become long-term survivors.
Current therapy includes the use of radiation for rectal and lower colon tumors, in conjunction with chemotherapy using 5-FU with leucovorin. Other agents, including irinotecan, may be of value.[Level of evidence: 3iiiA] No significant benefit has been determined for interferon-alpha given in conjunction with 5-FU/leucovorin. A recent review of nine clinical trials comprising 138 patients younger than 40 years demonstrated that the use of combination chemotherapy improved progression-free and overall survival (OS) in these patients. Furthermore, OS and response rates to chemotherapy were similar to those observed in older patients.
(Refer to the PDQ summaries on adult Colon Cancer Treatment and Rectal Cancer Treatment for more information.)
These tumors, like bronchial adenomas, may be benign or malignant and can involve the lining of the lung, large or small bowel, or liver.[101,102,103,104,105,106] Most lung lesions are benign; however, some metastasize.
Most carcinoid tumors of the appendix are discovered incidentally at the time of appendectomy, and are small, localized tumors; simple appendectomy is the therapy of choice.[108,109] For larger (>2 cm) tumors or tumors that have spread to local nodes, cecectomy or rarely, right hemicolectomy, is the usual treatment. It has become accepted practice to remove the entire right colon in patients with large carcinoid tumors of the appendix (>2 cm in diameter) or with tumors that have spread to the nodes; however, this practice remains controversial. A MEDLINE search did not find any documented cases of childhood localized appendiceal carcinoid in children younger than 18 years with complete resection who relapsed. Treatment of metastatic carcinoid tumors of the large bowel or stomach becomes more complicated and requires treatment similar to that given for colorectal carcinoma. (Refer to the PDQ summary on adult Gastrointestinal Carcinoid Tumors for therapeutic options in patients with malignant carcinoid tumors.)