Analysis of the effect of menopausal status and molecular subtype on survivals among breast cancer patients

Abstract

Objective: To analyze the associations between molecular subtypes and overall breast cancer survival among premenopausal and postmenopausal breast cancer in Beijing, and to provide basic information for breast cancer clinical researches and control. Methods: All the resident patients diagnosed with breast cancer in four well-established hospitals were retrieved from Beijing cancer registry, related information, such as TNM stages, receptor status, histological grade, height, weight, were collected by case extraction. Cancer registration information and population-based follow-up information were used to acquire survival outcome. All the patients were followed up until 31 December 2015, 4 531 cases with invasive, primary breast were included in the final analysis. All the cases were classified into Luminal and non-Luminal according to receptor status. Five-year survival rates of the two subtypes were estimated by the life-table method. Multivariable Cox proportional hazards models were employed to evaluate the associations between molecular subtypes and breast cancer survival. Results: Of all the 4 531 patients, premenopausal patients accounted for 44.5% (2 017 cases) and postmenopausal patients accounted for 55.5% (2 514 cases). 643 cases died during the study period. Overall five-year survival was 89.5% (95%CI: 88.6%-90.4%), for premenopausal and postmenopausal patients, they were 92.1% (95%CI: 90.9%-93.3%), and 87.5% (95%CI: 86.2%-88.8%), respectively. Among all the patients, 3 730 patients had molecular subtype, 76.7% (2 861 cases) were Luminal breast cancer, and 23.3% (869 cases) were non-Luminal breast cancer. Five-year survival rates for Luminal and non-Luminal were 91.8% (95%CI: 90.8%-92.8%), and 83.2% (95%CI: 80.7%-85.7%), respectively. No matter in premenopausal or postmenopausal patients, non-Luminal breast cancer had significantly higher risk of death compared to Luminal breast cancer (premenopausal: HR=1.85, 95%CI: 1.26-2.73; premenopausal: HR=1.42, 95%CI: 1.07-1.88). Conclusion: For both premenopausal and postmenopausal breast cancer patients, non-Luminal breast cancer had lower five-year survival rates than Luminal breast cancer, which was a risk factor on breast cancer survival.