Increased thyroid cancer risk in acromegaly

Acromegaly increases cancer risk. We aimed to determine the prevalence and the predictors of tumors in acromegalic patients treated at our department. We retrospectively evaluated 160 acromegalic patients [79 female (mean age 52.0 ± 10.4 years) and 81 male (mean age 49.1 ± 12.4 years)] between 1990 and 2012, with a mean follow up period of 7.1 ± 5.7 years. The patients were screened with colonoscopy, mammography, thyroid and prostate ultrasonography. Malignancy was found in 34 (21.3 %) patients. No significant difference was observed in the distribution of malignancy among sexes (20.3 % in F vs. 22.2 % in M). Thyroid cancer was the most frequent (n = 17, 10.6 %) followed by the breast cancer (n = 4, 2.5 %) and colorectal cancer (n = 3, 1.8 %). Renal cell cancer in two patients, bladder cancer in two patients, periampullary tumor, rectal carcinoid tumor, malignant melanoma, prostate cancer, lung cancer, parotid mucoepidermoid carcinoma and malignant mesenchymal tumor in brain in one patient were detected. One patient had both thyroid and renal cell cancer. Age of patients at diagnosis of acromegaly was significantly higher in patients with cancer (45.8 ± 9.9 vs. 40.9 ± 11.3 years, p < 0.05). No significant difference was found in duration of the disease, initial GH levels and IGF-1 % upper limit of normal values, the prevalence of diabetes, hypertension, coronary heart disease, hyperlipidemia and treatment modalities between the patients with/without cancer. In logistic regression analysis, older age at diagnosis was associated with malignancy risk. The risk of cancer in acromegaly especially the thyroid cancer risk seems to be more increased than known in the literature. Therefore, acromegaly patients should be screened routinely for cancer, especially for thyroid cancer due to it being up to four times higher prevalence than breast and colorectal cancer.