The Breast-Thyroid Lesions Link: A Cross-Sectional Study Based on Ultrasonography in China

Background: In China's health examination centers, asymptomatic individuals usually (can choose to) undergo screening by breast and thyroid ultrasound scans. It is reported that there are links between breast cancer and thyroid disorders, but in screening series the association of breast and thyroid lesions is not clear. Therefore, we retrospectively investigate it based on the ultrasound examinations among healthy women in China.   Methods: We conducted this study using data from the Quality Control Center of Health Examination in Chongqing, China, from Jan 2015 to Jun 2017, including 34184 consecutive women with synchronized breast and thyroid ultrasound scans. Ultrasound detected lesions were assigned into categories of different malignant risk according to the breast and thyroid Imaging Reporting and Data System (B/TI-RADS). We used binomial logistic regression to determine the association between the occurrences of breast mass(es) (BM) and thyroid nodule(s) (TN), and used multinomial logistic regression to analyze the correlation of BM and TN with different RADS categories. Furthermore, we explored the anthropometric and biochemical risk factors for BM and TN, respectively.   Findings: Of 34184 asymptomatic women enrolled, 6371 (18·6%) had BM, 12153 (35·6%) had TN and 2279 (6·7%) had both of them; 882 (2·6%) had BM with BI-RADS category ≥4, accounting for about 13·8% of the total BMi; 7395 (21·6%) had TN with TI-RADS category ≥4, accounting for about 60·8% of the total TN. After being adjusted for age, body mass index (BMI) and height, females with TN had a higher occurrence rate of BM than those with normal thyroid scans (OR 1·151, 95%CI 1·081 to 1·225; p<0·0001), and vice versa (BM vs Non-BM; OR 1·165, 95%CI 1·096 to 1·238; p<0·0001). The breast-thyroid lesions link was stronger in those with a higher malignant risk, especially strongest in the BI-RADS category ≥4A BM with TI-RADS category ≥4C TN (OR for BI-RADS ≥4A 1·904, 95%CI 1·485 to 2·440, p<0·0001; OR for TI-RADS ≥4C 1·915, 95%CI 1·494 to 2·455, p<0·0001). In addition, the increased risk of BM was associated with lower levels of BMI, plasma albumin and a higher level of height; the increased risk of TN was associated with higher levels of BMI, height, systolic blood pressure and a lower level of plasma albumin.   Interpretation: Breast and thyroid lesions are more inclined to occur together in the same individuals than by chance, especially in those with higher malignant risk.   Funding: None. Declaration of Interest: The authors declare that there is no duality of interest associated with this manuscript. Ethical Approval: This study was approved by the Ethics Committee of The First Affiliated Hospital of Chongqing Medical University and conducted in accordance with the Principles of the Helsinki. Declaration. Requirement for informed consent was waived because all information was anonymous.