Colon Cancer and Polyps in Acromegaly: Increased Risk Associated With Family History of Colon Cancer

SUMMARY A cohort of 52 subjects diagnosed with acromegaly in southeastern Michigan and northern Ohio between 1935 and 1985 were followed to determine the incidence of colon cancer and polyps. Medical records were reviewed, subjects or their next‐of‐kin were interviewed, and screening examinations of the colon were offered to the living patients who were located. Data on demographics, personal histories of cancer and colon polyps, family history of colon cancer, and cure from acromegaly were obtained for both living and deceased subjects. The risk for colon cancer compared to the general population was estimated using standardized incidence ratios (SIRs). The expected number of cases was determined utilizing age, sex and race‐specific rates provided by the cancer registry in southeastern Michigan. Among the 52 subjects, one could not be located and nine were deceased, none from colon cancer, with one known to have a history of colon polyps. Of 13 (31 %) who declined the screening physical, one had a history of polyps and none reported a history of colon cancer. Two of 29 screened patients were found to have right‐sided adenocarcinoma of the colon. Of the entire cohort, eight people (including one deceased) had a current or previous diagnosis of polyps, with five known to be histologically adenomatous. The SIR for colon cancer was 4.7 (95% confidence interval 0.6–17.1). Seven subjects, including the two with detected adenocarcinoma and four of the six living subjects with polyps only, reported a family history of colon cancer. The SIR for the subset of subjects with a family history of colon cancer was 29.1 (95% confidence interval of 3.5–104.6). Logistic regression analysis of the subset of the acromegalic cohort that was screened demonstrated that family history of colon cancer and male gender were predictive of the presence of colonic neoplasms at P < 0.001 and P < 0.009, respectively. This study supports the association between acromegaly and colon cancer reported by others and suggests that an increased risk of colon cancer in these patients may be associated with a family history of colon cancer. We recommend that patients with acromegaly routinely undergo colon cancer screening, particularly those with a positive family history for colon malignancies.