Omega-3-polyunsaturated fatty acid eicosapentaenoic acid in the free fatty acid form has been shown to reduce rectal polyp number and size in a small study of patients with FAP post subtotal colectomy. Although not directly compared in a randomized trial, the effect appeared to be similar in magnitude to that previously observed with celecoxib.
It is unclear at present how to incorporate COX-2 inhibitors into the management of FAP patients who have not yet undergone risk-reducing surgery. A double-blind placebo-controlled trial in 41 APC mutation carrier children and young adults who had not yet manifested polyposis demonstrated that sulindac may not be effective as a primary treatment in FAP. There were no statistically significant differences between the sulindac and placebo groups over 4 years of treatment in incidence, number, or size of polyps.
Consistent with the effects of COX-2 inhibitors on colonic polyps, in a randomized, prospective, double-blind, placebo-controlled trial, celecoxib (400 mg, administered orally twice daily) reduced, but did not eliminate, the number of duodenal polyps in 32 patients with FAP after a 6-month course of treatment. Of importance, a statistically significant effect was seen only in individuals who had more than 5% of the duodenum involved with polyps at baseline and with an oral dose of 400 mg, given twice daily. A previous randomized study of 24 FAP patients treated with sulindac for 6 months showed a nonsignificant trend in the reduction of duodenal polyps. The same issues surrounding the use of COX-2 inhibitors for the treatment of colonic polyps apply for their use for the treatment of duodenal polyps (e.g., only partial elimination of the polyps, complications secondary to the COX-2 inhibitors, and loss of effect after the medication is discontinued).
Because of reports demonstrating an increase in cardiac-related events in patients taking rofecoxib and celecoxib,[164,165,166,167] it is unclear whether this class of agents will be safe for long-term use for patients with FAP and in the general population. Also, because of the short-term (6 months) nature of these trials, there is currently no clinical information about cardiac events in FAP patients taking COX-2 inhibitors on a long-term basis.
Level of evidence for celecoxib study: 1
One cohort study has demonstrated regression of colonic and rectal adenomas with sulindac (an NSAID) treatment in FAP. The reported outcome of this trial was the number and size of polyps, a surrogate for the clinical outcome of main interest, CRC incidence.
Level of evidence for sulindac study: 1
Patients who carry APC germline mutations are at increased risk of other types of malignancies, including thyroid cancer, small bowel cancer, hepatoblastoma, and brain tumors. The risk of these tumors, however, is much lower than that for colon cancer, and the only surveillance recommendation by experts in the field is upper endoscopy of the gastric and duodenal mucosa.[9,22] The severity of duodenal polyposis detected appears to correlate with risk of duodenal adenocarcinoma. (Refer to the Duodenum/small bowel tumors section and the Other tumors section in the Major Genetic Syndromes section of this summary for more information about screening for extracolonic malignancies in patients with FAP.)