Positive anti-TG antibody is associated with increased breast cancer risk in Turkish peri-postmenopausal women: A retrospective study

Background: Breast cancer is one of the most common types of cancer in women worldwide. Thyroid hormones play an important role in regulating metabolism and cell growth, including in breast tissue. Although a potential link between thyroid health and breast cancer risk has been suggested in the literature, highly conflicting results have been obtained, and the relationship between them remains unclear. This study aimed to examine the possible association between breast cancer and thyroid health in Turkish women with breast cancer. Methods: For this retrospective study, data from 66587 women aged between 18 and 80 years who had any complaints of thyroid function tests were collected, and the thyroid stimulating hormone (TSH), free thyroxine (fT4), anti-thyroid peroxidase (anti-TPO), and anti-thyroglobulin (anti-TG) levels of 3115 women with breast cancer and peri-postmenopausal women with breast cancer who met the inclusion criteria were analysed. The relationship between thyroid function and breast cancer risk was examined using logistic regression analysis. In addition, this association in peri-postmenopausal women was further investigated with receiver processing characteristic (ROC) curve analysis. Results: A total of 3115 Turkish women, including a subgroup of peri-postmenopausal women aged 40 years and older, participated in the study. The fT4, TSH, anti-TPO, and anti-TG levels were assessed in both the overall group and the peri-postmenopausal subgroup. The median anti-TG level was significantly greater in women with breast cancer and peri-postmenopausal breast cancer than in women with anti-TG-negative breast cancer (p < 0.05). No statistically significant differences were found in the median fT4, TSH, or anti-TPO levels between the groups (p > 0.05). A significant positive association was observed between anti-TG antibody levels and breast cancer in Turkish women (OR = 3.325, 95% CI = 1.625–6.803, p = 0.001), with a stronger association in peri-postmenopausal women (OR = 3.57, 95% CI = 1.691–7.540, p = 0.001) Conclusions: In conclusion, our study indicated that anti-TG positivity is associated with an increased risk of breast cancer. These findings highlight the importance of routine screening for thyroid antibody levels in women, particularly those in the peri-postmenopausal period. However, further prospectively designed studies are necessary to confirm these results.