Comparison of the sensitivity to endocrine therapy of PR+/ER- patients and ER+/PR- patients with HER2+ breast cancer
e11558 Background: Her2 and PR expression are important indicators for prognosis of breast cancer. Aslo, it's proved that their expression could guide chemotherapy, endocrine therapy and targeted therapy in many studies. Methods: Collected 3,677 primary breast cancer cases from 2002 to 2004 in Tianjin University Cancer Hospital. All of the cases were confirmed by pathohistological method. All patients are female, aged from 15 to 92 years old, with median age 50 years old. Median follow-up time is 40 months. Her-2, PR and ER expression were detected by immunohistochemical methods. Results: 1. With Her2+ breast cancer, 168 patients are PR+/ER- and 211 patients are ER+/PR-. 2. All patients treated with anthracycline-based adjuvant chemotherapy with 6 cycles and then given endocrine therapy: Pre-menopausal patients were given TAM (10mg P.O Bid); Post-menopausal patients were given AI (letrozole 2.5m po. bid or anastrozole 1 mg P.O Qd). Median follow-up time is 45 months. With Her2+ BC, 3-year DFS(disease-free survival rate) of PR+/ER- patients is 94.53%, higher than that of PR-/ER+ ones (91.81%).With Her2- BC, 3-year DFS of PR+/ER- patients is lower than that of PR-/ER+ (p<0.05). 3. Total of 1853 cases with 5-year followed up, and 1297 cases have been given endocrine therapy. 5-year overall survival rate was 83.41%. With Her2+ BC, it's significant difference that 5-year OS of PR+/ER- patients is higher than that of PR-/ER+ ones. However, there's no difference of 5- year OS between them with Her2- BC. Conclusions: With Her2+ breast cancer, 3-year DFS of PR+/ER- patients is higher than ER+/PR- and also PR+/ER- patients may more sensitive to endocrine therapy than ER+/PR- patients. No significant financial relationships to disclose.