Prevalence of breast cancer in thyroid diseases: results of a cross-sectional study of 3,921 patients

Abstract

Results from national cancer registries reveal an association of thyroid cancers with extra-thyroidal malignancies. In this study, we evaluated the prevalence of breast cancer (BC) in women affected by both benign and malignant thyroid diseases (TD) in comparison to the general population. To this end, 3,921 female patients from central and southern regions of Italy were evaluated. Age-matched analysis of the prevalence of BC was carried out after dividing the patients into three diagnostic categories: (1) 1,149 patients with non-nodular TD; (2) 2350 patients with nodular TD; (3) 422 patients affected by differentiated thyroid cancers. Furthermore, the patients were grouped according to the absence (2,344 patients) or presence (1,453 patients) of anti-thyroglobulin (TgAb) and/or anti-thyroperoxidase (TPOAb) or anti-TSH receptor auto-antibodies (124 patients). BC prevalence in TD patients as a whole was significantly higher compared to the general population, with an odds ratio (OR) of 3.33. Age-matched analysis showed that the risk of a BC in TD patients was higher in younger patients (age 0-44 years), with an OR of 15.24, which decreased with increasing age. Patients without thyroid auto-antibodies showed a higher OR for BC (p = 0.0005) than TD patients with TgAb and/or TPOAb. The results demonstrate that women affected by either benign or malignant thyroid disease have a significantly greater risk of BC, which is higher at a younger age. Furthermore, thyroid auto-antibodies appear to be protective against BC. These findings may contribute to the identification of common genetic and environmental factors underlying this disease association.

Relationship between Breast Cancer and Levels of Serum Thyroid Hormones and Antibodies: a Meta-analysis

“…We found that BC patients had higher levels of TPOAb and TgAb than controls. However, our findings were in disagreement with those of Prinzi et al (2014), who showed that the presence of thyroid auto-antibodies is protective against BC. That study differed from the current study in that they used qualitative data to determine thyroid disease, and they showed functional sensitivities for TgAb (positivity﹥60 U/ml) and TPOAb (positivity﹥60 U/ml).…”

Antithyroid peroxidase antibody positivity is associated with lower incidence of metastasis in breast cancer

“…However, we were unable to identify any association between nuclear grade, ER, PgR and HER2̸neu status, lymph node involvement and TPOab positivity. In March, 2014 a study conducted in Italy demonstrated that breast cancer prevalence is higher among patients with thyroid diseases; however, the subgroup analysis demonstrated that TPOab and/or antithyroglobulin antibody positivity appear to be protective against breast cancer (26).…”

The prevalence of benign breast diseases in patients with nodular goiter and Hashimoto’s thyroiditis

“…This issue needs clarification with further research both pathophysiologically and clinically. Most of these studies have commonly emphasized the necessity of screening for breast cancer in patients with thyroid disorders [13][14][15][16][17][18].…”