Endocrine Abstracts

Aim: In this study, we aimed to evaluate ABO blood groups and Rh factor in patients with thyroid cancer. We also assessed whether the ABO/Rh factor had any effect on prognosis, agressive features and advanced stage of thyroid malignancies.

Methods: Medical records of patients who underwent thyroidectomy between December 2006 and September 2014 were evaluated retrospectively. Demographical and clinical features, cytological results (according to Bethesda classification), ABO blood groups and Rh factor status of patients with benign and malignant thyroid disease were compared. Additionaly, in malignant group, histopathological features were compared in patients with different ABO blood groups, and Rh positive and negative patients.

Results: Histopathological diagnosis was benign in 1299 (63.5%) and malignant in 744 (36.5%) patients. There were no significant difference in age, sex, thyroid autoantibody positivity and ABO blood groups in benign and malignant patients (P>0.05 for each). Ratio of Rh positive patients was significantly higher in malignant compared to benign group (91.8% vs 88.1%, P<0.046). In all subgroups of cytology, malignancy rates were similar in different ABO blood groups, and Rh positive and negative patients. Considering malignant patients, extrathyroidal extension and advanced stage (3–4) were more prevalant in patients with B compared to non-B blood groups (P=0.028 and P=0.042, respectively). Patients with O blood group had lower rate of capsular invasion than patients with non-O blood groups (P=0.018). ABO blood groups or Rh status were not associated with thyroid cancer in this study. However, patients with B blood group had higher risk of extrathyroidal extension and advanced stage compared to patients with non-B blood group.

Conclusion: For the first time in our study, we evaluted the association of Rh factor status and thyroid cancer, and found no significant relation. ABO blood groups also did not increase malignancy risk in thyroid nodules. In malignant patients, extrathyroidal extension and advanced stage were higher in B compared to non-B blood groups. Our findings can be considered as a preliminary to investigate ABO blood groups and Rh status as factors that can identify patients with higher risk.