Endocrine Abstracts

Introduction: There is little data about the influence of immunosuppression on the recurrence rate of thyroid cancer. We aimed to evaluate the risk of recurrence and mortality of thyroid cancer after solid organ transplantation.

Patients and Methods: We retrospectively evaluated 802 kidney and 283 liver transplant recipients who underwent transplantation between January 1999 and May 2019 in Bașkent University. We identified 14 patients with thyroid cancer. Of these 14 patients, 12 were kidney transplant recipients and 2 were liver transplant recipients. Thyroid cancer was classified as low/intermediate and high risk according to the 8th pTNM (tumor, node, metastasis) classification system as well as American Thyroid Association guidelines.

Results: Fourteen patients (seven males, seven females) with a history of both organ transplantation and thyroid cancer were recruited for this study. Median age of the patients was 42 (31–70) years. All of the patients were on corticosteroid,and mycophenolate mofetil was administered to 13 patients (92.9%), cyclosporin A to 10 patients (71.8%), tacrolimus to 1 patient (7.1%), andMammalian target of rapamycin (mTOR) inhibitors were used in 2 patients (14.3%). All patients underwent total thyrodectomy, except one patient who underwent total thyroidectomy and lateral neck dissection. Median age at diagnosis of thyroid cancer was 34 (18–65) years. Six of the patients (42.9%) were diagnosed pre-transplantation. Thirteen of the patients had papillary and one patient had follicular cancer. Nine of the patients (64.3%) had multifocal disease. All patients had stage I disease and also were in low risk group. Median follow-up time was 6.9 (1.3–14.6) years. After initial treatment, 13 of 14 patients were in remission. One patient with had local recurrence During the follow-up period, there were no signs of local recurrence or distant metastasis in the remaining 13 patients. None of the patients were lost to thyroid cancer.

Discussion: Our results suggest that solid organ transplantation does not influence thyroid cancer prognosis, especially in low risk patients. There is a concern about the progression of a previously treated cancer after transplantation. In this study, six of the patients were diagnosed and treated before transplantation. During follow-up, all of the patients were in remission. This indicates that transplantation may not alter the outcome of differentiated thyroid cancer.

In conclusion, our study suggests that thyroid cancer outcome is not altered after kidney and liver transplantation. Further studies in a larger population are needed.