Possible association between breast thyroid carcinoma: Analysis of risk factors

BACKGROUND: Breast cancer (BC) is the most common tumor in women, 523.000 cases were estimated in Europe in 2018 and it remains the third cause of cancer related deaths after lung and colorectal cancer. The incidence of thyroid cancer (TC) in females is higher than in males. METHODS: We have retrospectively collected all female patients undergone to surgery for breast or thyroid cancer in 2010The aim of the study was to value the incidence of BC in patients with a personal history of differentiated thyroid cancer (DTC) and conversely, the incidence of DTC in patients with previous BC within 5 years from the diagnosis of the first tumor in 2010. RESULTS: Among 76 BC patients, 11 were death and 22 didn’t answer the phone call or refused to re-submit to thyroid ultrasound so they were excluded from the study and only 43 BC were further considered. Thyroid ultrasound was performed in 2010 and in 2016 and it described nodules in 13 (30%) patients in 2010 and in 21 (49%) patients in 2016. In 2010 no FNA was needed while in 2016 6 (14%) patients underwent to FNA with a benign response (Thyr 2). Among 61 DTC patients, 11 didn’t answer the phone or the questions so 50 patients were included in the study. Breast cancer family history was reported in 14 (28%) patients and thyroid cancer family history in 8 (16%) patients. No relapse was reported during follow up.All patients underwent to mammography in 2015 or in 2016 within screening programs and no breast cancer were diagnosed. CONCLUSION: The female predominance of diseases of the thyroid and breast makes difficult the separation of an expected association with a casual linkageThe relationship between the co-occurrence of breast and thyroid cancer remains controversial and inconclusive.