Background

Association between breast cancer (BC) and thyroid nodules (TNs) is still unclear. This research was to estimate the prevalence and risk factors of TN in Chinese BC women at initial diagnosis.

Methods

1731 Chinese early-stage BC women at initial diagnosis underwent thyroid ultrasound and 1:1 age-matched Chinese healthy women underwent health examination in corresponding period were enrolled for analysis.

Results

Prevalence of TN and TI-RADS ≥ 4 TN in BC patients (56.27% and 9.76%) were higher than healthy people (46.04% and 5.49%), respectively, P < 0.001. Among BC patients, prevalence of TN and TI-RADS ≥ 4 TN in hormone receptor (HR)-positive patients (59.57% and 11.81%) were higher than HR-negative patients (48.77% and 5.10%), respectively, P < 0.001, while without difference between HR-negative patients and healthy people. After adjusting for age and BMI, HR-positive patients had higher risk of TN (OR = 1.546, 95%CI 1.251–1.910, P < 0.001) and TI-RADS ≥ 4 TN (OR = 3.024, 95%CI 1.943–4.708, P < 0.001) than HR-negative patients. Furthermore, the risk of TI-RADS ≥ 4 TN was higher in patients with estrogen receptor (ER) positive (OR = 2.933, 95%CI 1.902–4.524), progesterone receptor (PR) positive (OR = 1.973, 95%CI 1.378–2.826), Ki-67 < 20% (OR = 1.797, 95%CI 1.280–2.522), and tumor size < 2 cm (OR = 1.804, 95%CI 1.276–2.552), respectively, P < 0.001.

Conclusions

Prevalence of TN, especially TI-RADS ≥ 4 TN, in Chinese early-stage BC women was higher than healthy people. HR-positive patients had higher prevalence and risk of TN, while without difference between HR-negative patients and healthy people. The increased risk of TN was correlated with ER-positive, PR-positive, lower Ki-67 expression, and smaller tumor size.