Research Title: ABO Blood Types Can Play a Role in Determining Prognosis of Thyroid Cancer in Adult Patients: A Single-centre Retrospective Study.

Abstract

Background: Thyroid cancer is the most common endocrine malignancy. Previous research has linked the ABO blood group system to the risk and progression of different types of cancer. However, the association between specific blood groups and thyroid cancer risk and prognosis remains unclear. In this study, we aimed to investigate the relationship between ABO blood groups, thyroid cancer risk, and prognosis. Methods: All adult patients who underwent thyroidectomy in our centre between January 2012 and January 2021 were included. A total of 569 files were reviewed, and a total sample of 453 patients were matched after excluding patients with missing data. All sociodemographic, ABO blood groups, Rh factor, and histopathology records were accessed in the study. Result: Out of 435 patients, the majority had malignant thyroid diseases (69.9%). Papillary thyroid cancer was the most common (82.0%). Positive lymph nodes were found in 25% of patients, with blood type B having the highest rate (26.7%). Blood type AB had significantly higher rates of vascular invasion than all other blood types (40% vs 16.3%; p=0.03). Blood type AB was also associated with follicular subtype (20%), larger tumour size, higher capsular invasion (33.3%), and distant metastasis (6.7%). Meanwhile, blood type O had the lowest rates of both lymph node invasion and capsular invasion. Benign disease was significantly associated with hypothyroidism (p<0.001). Additionally, thyroiditis (31.8%) and Hashimoto’s (18.2%) were more common in blood Group B. Conclusion: Blood type AB had the highest rates of capsular invasion, vascular invasion, and distant metastasis compared to other blood types, indicating its potential aggressiveness. On the other hand, blood type O could be less aggressive than other blood groups.