Prevalence of thyroid cancer in patients with acromegaly and non-growth hormone secreting pituitary adenomas: A prospective cross-sectional study.

Objective: To evaluate the prevalence of differentiated thyroid cancer (DTC) in patients with non-GH secreting pituitary adenomas [NGHPA group: non-functioning (NFPA), prolactin (PRL) and corticotropin (ACTH)-secreting adenomas] compared to patients with acromegaly, a pituitary disease that has been associated with increased risk for thyroid cancer.

Patients And Methods: Prospective, cross-sectional study involving consecutive outpatients followed in our institution with diagnosis of acromegaly (n = 71; 43 women, median age 57 yrs) and NGHPA (n = 57; 38 women, median age 48 yrs.; PRL (n = 35), ACTH (n = 7), NFPA (n = 15). All participants were subjected to thyroid ultrasound (US) by the same examiner, and US-guided fine needle aspiration (FNA) biopsy when indicated.

Results: Thyroid volume was higher in acromegaly than in NGHPA (median 12.5 ml vs 6.3 ml; p < 0.0001), and thyroid nodules were present in 27/71 (38.0%) of acromegaly patients and in 14/57 (24.6%) of NGHPA group. FNA was indicated in 15/27 (55.5%) of acromegaly patients [Bethesda I (n = 1); II (n = 11), III (n = 1), two patients refused FNA], and in 8/14 (57.1%) of the NGHPA group [Bethesda I (n = 2); II (n = 4); V (n = 1); VI (n = 1)]. The two patients of NGHPA group with Bethesda V and VI were operated and papillary carcinoma was confirmed histologically.

Conclusion: DTC was not detected in our acromegaly patients and its presence in patients with NGHPA suggests that DTC predisposition is not related to GH excess.