Analysis of clinicopathological features of papillary thyroid carcinoma in solid organ transplant recipients: a retrospective study

BACKGROUND: With the advances in organ transplantation technology and the increased number of organ recipients, more organ transplant recipients are living longer. However, many newly-onset thyroid cancer cases have been found among this population. The question remains in the uncertainty in whether the post-transplant thyroid cancer is more pathologically aggressive than the thyroid cancer in non-organ-transplant recipients. We compared the clinicopathological features of papillary thyroid carcinoma (PTC) between solid organ transplant recipients (SOTR) and the general population, in an attempt to improve the detection rate of post-transplant PTC in SOTR and overall survival prognosis of those patients. METHODS: The clinical data of 408 PTC patients in the First Affiliated Hospital of Zhejiang University School of Medicine from July 2013 to April 2019 were retrospectively analyzed. The clinicopathological features were compared between non-organ-transplant recipients with PTC (group A, n=380) and SOTR with newly-onset PTC (group B, n=31) using Chi-square test, Fisher’s exact test, Student’s t-test, and logistic regression. RESULTS: There were significant differences between these two groups in central compartment lymph node metastasis (P=0.005), multifocality (P=0.003), and maximum tumor diameter (P=0.007). Compared with group A, group B had a higher rate of tumor multifocality, higher rate of lymph node metastasis, and smaller tumor size. In addition, PTC in group B was more aggressive in biological behaviors such as tumor multifocality and lymph node metastasis. CONCLUSIONS: Compared with the general population, PTC after SORT demonstrate a more malignant pathological feature. The examination rate of thyroid cancer in SORT should be increased to improve the overall prognosis after solid organ transplant.