The relationship between prognostic factors of breast cancer and thyroid disorders in Turkish women

Background: Breast carcinoma is a frequent disease that affects the female population. As for other malignant diseases, several studies have been carried out in an attempt to identify its etiology, yet the etiological agent has not been clearly defined. The etiological relationship between thyroid disease and breast cancer is still being investigated. However, most of the studies in this field are conflicting and discussions on this relationship still continue.

Patients and method: Our prospective open study was conducted on 136 consecutive patients operated for breast carcinoma. As a control group, 68 individuals with normal breast examination, who did not have any known malignancy and/or thyroid disease, living in the same geographical region and with matching socio-cultural and economical status, were included in the study. We aimed to identify the occurrence and frequency of thyroid pathologies in both groups to compare the clinical and the laboratory features of thyroid disease and breast carcinoma in an attempt to contribute to the studies investigating the relationship between these two entities.

Results: We found thyroid pathology in 77.9% of breast cancer patients while this was 47.1% in the control group. Breast cancer patients had higher levels of free-T3 and more frequent diffuse and nodular enlargement of thyroid gland in ultrasonography when compared to the control group. Furthermore, in the presence of thyroid disease, breast cancer patients had statistically significant increases in the number of metastatic lymph nodes, vascular invasion, and tumor size.

Conclusion: In conclusion, the frequency of thyroid pathology is higher in breast cancer patients compared to controls indicating a relationship between breast carcinoma and thyroid pathology. Our study shows that the presence of thyroid pathology in breast cancer patients can be influential on the spread of cancer and adversely affect its prognosis. We thought further studies are needed to confirm these findings and to explain the reason for co-occurrence of breast cancer and thyroid disease and furthermore to investigate the prognosis and survival of breast cancer patients in the presence of thyroid pathology.