The association between breast cancer and thyroid cancer: a meta-analysis

Abstract

Previous studies have suggested an association between breast cancer and thyroid cancer; however, there has not been a formal meta-analysis which collates the existing evidence supporting the hypothesis that breast cancer or thyroid cancer predisposes an individual to developing the other. A systematic search was carried out using PubMed and Medline. We searched for articles containing epidemiological evidence of breast cancer following thyroid cancer and vice versa. Additionally, we searched for articles that included epidemiological data involving the incidence of all second primary malignancies (SPMs) following both breast cancer and thyroid cancer, and compared the datasets. The meta-analysis performed in a total of 18 studies showed that there is a significantly increased risk of developing thyroid cancer as a second primary malignancy of breast cancer (SIR = 1.59, 95 % confidence interval (CI) 1.28-1.99). Additionally, there was marginally increased risk of developing breast cancer as a second primary malignancy of thyroid cancer (SIR = 1.24, 95 % CI 1.16-1.33), compared to the general risk of developing a second primary malignancy following thyroid cancer. The findings suggest that the risk of developing thyroid cancer as a second primary malignancy of breast cancer and vice versa is increased compared to the background risk of developing other SPMs. The risk of developing thyroid cancer after a primary breast cancer was higher than the risk of developing breast cancer as a second primary malignancy of thyroid cancer. This suggests that the effects of treatment-related factors and specific pathological processes of each cancer may contribute to the increased risk rather than common risk factors including genetic factors. Elucidation of the common mechanisms between breast cancer and thyroid cancer will have important implications in both diagnostic and therapeutic management of these cancers. Benefit of thyroid ultrasound screening after breast cancer surgery needs to be assessed.

Spatiotemporal Co-existence of Female Thyroid and Breast Cancers in Hangzhou, China

“…The β TC and β BC values, which provide a quantitative assessment of the magnitude of the TC-BC association, were found to be practically identical, as should be expected, since both coefficients refer to the same TC-BC association. The result of Eqs (9, 10) further support the spatiotemporal co-existence of TC and BC incidence distributions at the population level, according to the IDP criterion, and are in agreement with some earlier findings suggesting the co-existence of TC and BC diseases17394041.…”

“…Indeed, several researchers have suggested that due to common risk factors there may exist a strong association between TC and BC incidence4041.…”

Genetic Heterogeneity of HER2 Amplification and Telomere Shortening in Papillary Thyroid Carcinoma

“…Familial PTC may occur in combination with other Mendelian cancer syndromes (familial adenomatous polyposis, Gardner’s syndrome, Peutz-Jeghers syndrome, and Cowden’s syndrome) or may be unassociated with other neoplasms in familial aggregates. However, although the risk of developing extra-thyroidal malignancy in non-Cowden’s syndrome is documented [21,22], the clinical correlation between sporadic breast cancer (20% of which are HER2+ ) [23] and PTC is still controversial [24,25], and the co-occurrence of both disorders in the same individual is a subject of extensive debate [26,27]. None of our fPTC patients had clinical or pathological evidence of hereditary syndromes associated with NMTC, breast cancer, or other types of sporadic tumors, except for one male patient who had a previous squamous cell carcinoma of the auricle.…”

Risk of Breast Cancer in Patients with Thyroid Cancer Receiving or Not Receiving 131I Treatment: A Nationwide Population-Based Cohort Study

“…Physicians may propose that patients with thyroid cancer perform breast self-examinations periodically and undergo ultrasonic mammography regularly. It has been reported that there is an association between breast cancer and thyroid cancer; this association may be attributable to common etiologic features, pathologic processes, or treatment-related factors (27,28) that these 2 cancers share. Previous studies suggested the relationship between serum levels of thyroid hormones or thyroid peroxidase autoantibodies and the risk or prognosis of breast cancer (29)(30)(31)(32).…”