Inducing or Preventing Subsequent Malignancies for Breast Cancer Survivors? Double-edged Sword of Estrogen Receptor and Progesterone Receptor.

INTRODUCTION: Hormone receptor and human epidermal growth factor receptor 2 (HER2) status is important for breast cancer (BC) treatment. Previous studies have shown that the long-term treatment outcomes of BC are significantly impaired by the development of subsequent malignancies. Therefore, in the present study, we evaluated the effect of hormone receptor/HER2 status on subsequent malignancies in breast cancer survivors.

METHODS AND MATERIALS: The Surveillance, Epidemiology, and End Results*Stat database (8.3.4) was used as the data source. We identified 535,941 female survivors with first primary BC through the database from 1973 to 2013. Of these patients, 23,964 had developed subsequent contralateral BC, 8398 had developed subsequent uterine or ovarian cancer, and 7435 patients had developed subsequent colorectal cancer.

RESULTS: Estrogen receptor (ER) positivity and progesterone receptor (PR) positivity were significant protective factors against subsequent BC and ovarian cancer. However, ER+ BC and PR+ BC were significant risk factors for subsequent colorectal cancer. In addition, HER2+ status demonstrated a marginally significant risk effect for subsequent thyroid cancer. Triple-negative (ER- /PR- /HER2- ) status showed elevated risk of subsequent breast, ovarian, and uterine cancer.

CONCLUSION: ER+ /PR+ patients were less likely develop secondary breast and ovarian malignancies, possibly owing to advancements in anti-ER/PR treatment. However, ER+ /PR+ patients were more likely to develop colorectal cancer, suggesting a potential screening necessity for these patients.