Relationship between Breast cancer and Thyroid disorders

Background: The relationship between breast cancer and benign thyroid disease is controversial and the results of published studies have been conflicting. This study aimed at evaluating the prevalence of thyroid disease in patients with breast cancer and comparing the results with individuals without cancer. Methods: In this retrospective case–control study, the demographic factors, basic characteristics of the tumor and thyroid function tests (T3, T4, TSH) and number of patients with thyroid disorders, hypothyroidism and hyperthyroidism were measured in 100 breast cancer patients and 100 control individuals and the results were compared between the two groups. Results: According to our results, there was no significant difference between the two groups in terms of demographic factors. Also, thyroid dysfunction was found in 15% of patients and 19% of the controls, and hypothyroidism and hyperthyroidism were 6% versus 8% and 9% versus 11% in cancer patients and control patients, respectively. The difference was not statistically significant. Conclusion: Our prospective study did not show any significant difference in the prevalence of thyroid disorders between the patients with breast cancer and the individuals without cancer.