Thyroid cancer in patients with acromegaly: a case-control study.

Several studies have associated acromegaly with an increased risk of benign and malignant tumors. While simple and multinodular goiters are common findings in acromegaly, the prevalence of thyroid cancer is uncertain. The objective of this study was to estimate the prevalence of thyroid cancer in a series of acromegalic patients from three hospitals in northeast of Brazil. The methodology used included morphological, cytological and histological thyroid analysis of acromegalic patients and volunteers over 18 years, matched for age and sex and with nodule (s) ≥1 cm. The subjects of this study were 124 acromegalic patients, including 76 females (61.3%) and 48 men (38.7%), with a mean age 45.1 years. Results of the study showed that thyroid ultrasonography was normal in 31 cases (25%), 25 had diffuse goiter (20.1%), 67 had nodules (54%) and one agenesis of the right lobe (0.8%). Thirty-six patients underwent fine needle aspiration biopsy (FNAB) of their nodules and 9 cases of papillary cancer were found (7.2%). The control group consisted of 263 subjects, 156 females (59.3%) and 107 males (40.7%), mean age 44.7 years. In ultrasound assessment, 96 had nodules (36.5%). Of these, 13 were punctured and 2 cases of papillary carcinoma were found (0.7%). These results gave an odds ratio of 10.21 (p = 0.0011, 95% CI 2.17 to 48.01). These findings demonstrate an increased prevalence of thyroid cancer, statistically significant when compared to our control group. Thus, it is suggested that acromegalic patients should be routinely submitted to thyroid ultrasound evaluation, followed by FNAB of nodules when indicated.