Background: This study was designed to evaluate the relationship between estrogen receptor (ER) and progesterone receptor (PR) expression status and clinical outcomes in advanced breast cancer patients undergoing first-line endocrine therapy.
Methods: Data from 225 advanced breast cancer patients admitted to Henan Cancer Hospital from February 2010 to October 2019 were collected and compared using Chi-squared tests, with Cox regression models being used to identify relevant prognostic factors in these patients.
Results: PR+ and PR- patients had significantly different median progression-free survival (PFS) times of 25 months (95% CI: 13.50-36.50) and 7 months (95% CI: 4.03-9.97), respectively (P<0.001). Clinical benefit rates (CBR) were also significantly different between these 2 groups (80.9% and 55.6%, respectively; P<0.001). A subgroup analysis of PR+ and PR- patients that underwent aromatase inhibitor (AI) treatment revealed a median PFS of 25.0 months (95% CI: 14.28-35.72) and 7 months (95% CI: 4.18-9.82), respectively (P<0.001), and CBR values of 81.3% and 54.5%, respectively (P<0.001). In addition, for both the whole cohort and the AI subgroup, the total survival of patients with ER+/PR+ breast cancer was longer than that of patients with ER+/PR- breast cancer, and the difference was statistically significant (P<0.001).
Conclusions: ER+/PR+ advanced breast cancer patients had a better prognosis than ER+/PR- advanced breast cancer patients undergoing first-line endocrine therapy. In addition, we found that PR status was an independent predictor of first-line endocrine therapy responses in hormone receptor-positive HER2 negative patients.
Keywords: ER+/PR−; Estrogen receptor (ER)+/progesterone receptor (PR)+; first-line endocrine therapy.