Spectrum of thyroid diseases in women with breast cancer

Many scientific researches have focused attention to the possible associations between breast cancer (BC) and thyroid diseases (TD), mainly thyroid carcinoma (TC) and autoimmune thyroid diseases (ATD), but the question is still controversial. This study has evaluated the occurrence of TD in 131 women, mean age 59 years, coming from a mild-moderate iodine deficiency area, affected by BC ( group BC), examined at the thyroid centre of the University of Roma “Sapienza”. One hundred and forty-five women affected by different thyroid diseases without BC have been considered as control groups (group C); they have been recruited in order to have the same range of age and the same iodine uptake area. All patients were submitted to hormonal dosage of, FT4, TSH, thyroperossidase antibodies (TPO-Ab) and thyroglobulin antibodies ( Tg-Ab) and they underwent to thyroid ultrasography . As reported by several studies, the prevalence of thyroid diseases in woman previously affected by BC is increased with respect to the general population. This study has shown an increase of prevalence of ATD in group BC versus group C (ATD: 36,6% vs 28,7%) and has confirmed that ND is the most frequent disease in all groups observed (48,1% vs 48%). No relevant increase of TD has been recorded in patients with BC treated by postoperative therapy, both radiotherapy and chemotherapy. Therefore an increased risk of TD, in particular ATD, related to breast cancer and based on unknown pathways is confirmed. Several pathogenetic approaches, like an autoimmune response against some enzymatic activity (sodium/iodide symporter (NIS) or peroxidase), shared by thyroid and breast, have been thought to explain the association between BC and ATD. This pathogenetic hypothesis need however further researches and in every case this study emphasizes the necessity of thyroid screening in patients with breast cancer.