Incidence of thyroid dysfunction and thyroid cancer in renal transplant recipients: a single center experience

The prevalence of thyroid cancer in renal transplant population has not been widely studied, and there is no consensus on the management of thyroid cancer in transplant patients. The aim of this study was to evaluate changes in thyroid hormone levels and investigate the incidence of the thyroid cancer after renal transplantation.

From October 1989 to April 2007, 122 renal allograft recipients that were being followed underwent thyroid ultrasonography to determine nodules together with thyroid hormone levels. Ultrasound-guided fine-needle aspiration biopsy (FNAB) was performed to the nodules > 10 mm or those with 8-10 mm diameter but with calcifications.

One hundred and eight patients (88.5%) had normal thyroid function. None of the patients had overt hypothyroidism, 2 had subclinical hypothyroidism, 10 subclinical thyrotoxicosis, and 2 low T3 syndrome. Mean thyroid volume was 14.2 +/- 7.2 ml. In all, 91.8% was diagnosed with goiter (n = 112). Seventy-two thyroid nodules were detected in 49 kidney allograft recipients (single nodule in 30, multiple in 19 patients). Eighty-four biopsy samples were reported as benign (n = 21, 87.5%), 8 as suspicious (n = 2, 8.3%), and 4 as inadequate (n = 1, 4.1%). After surgery, one of the patients (0.8%) with suspicious FNAB was reported as papillary thyroid carcinoma.

Because of the high incidence of thyroid dysfunction in transplant patients, screening of thyroid function should be a part of follow-up. Our results suggest that although frequency of nodules is increased in kidney transplant patients, prevalence of thyroid cancer is slightly, but not significantly, higher than that of the normal population.