J Endocr Surg.  2020 Dec;20(4):88-96. 10.16956/jes.2020.20.4.88.

High Incidence and Prevalence of Papillary Thyroid Cancer in Breast Cancer Patients

• Park JH
• Kim S
• Kim LS

• KMID: 2511855
• DOI: http://doi.org/10.16956/jes.2020.20.4.88

Abstract

Purpose
Breast and thyroid cancers are the two most commonly diagnosed cancers in women. Many studies have described an increased risk of thyroid cancer in breast cancer patients. This may be related to hormonal exposure, genetic susceptibility, detection bias, and cancer treatment. We thus performed a retrospective descriptive study which aimed to assess the incidence and prevalence of thyroid cancer in breast cancer patients.
Methods
We reviewed electronic medical records of breast cancer patients who had undergone surgery between January 2013 and December 2017 in a single tertiary hospital. Patients with recurrent breast cancer, distant metastases, or previous history of thyroidectomy were excluded. A total of 966 patients were enrolled.
Results
A total of 37 (3.8%) patients were diagnosed with both breast and thyroid cancers during 46 months of median follow up. There were 28 (75.7%) synchronous cases diagnosed within 1 year, and 9 (24.3%) metachronous cases diagnosed after 1 year. The median age was 49 years (range, 30–65 years); 34 (91.9%) had thyroid microcarcinoma of less than 1 cm. The incidence and prevalence of thyroid cancer were 2.05 (95% confidence interval [CI], 0.93–3.61) times and 1.41 (95% CI, 0.93–1.98) times higher than those of general population, respectively.
Conclusions
The high incidence and prevalence of thyroid cancer among breast cancer patients are mostly attributable to the widespread screening with ultrasonography. Treatment strategies can be individualized with respect to the tumor characteristics, the patient's preference, and surgical resources.

Keyword

Breast neoplasm; Thyroid neoplasm; Ultrasonography