Rectal cancer after sulindac therapy for a sporadic adenomatous colonic polyp.

Like adenomatous polyps in familial adenomatous polyposis, some sporadic colorectal polyps have been reported to regress in response to sulindac administration. However, a rapidly growing invasive rectal cancer developed in one of 15 patients with sulindac-treated sporadic adenomatous colorectal polyps 16 months after sulindac treatment. In this patient, both the adenomatous polyp that responded partially to sulindac and the rectal cancer developing after sulindac therapy showed immunostaining for cyclooxygenase-2. Although short term sulindac therapy seems to be able to cause some adenomatous colorectal polyps to regress, 4 months of sulindac therapy may not reliably prevent colorectal cancer development in these patients.