Survival and recurrence of breast cancer patients: a single-center retrospective study

Abstract

Objective To explore the long-term OS and recurrence-free survival (RFS) and the influencing factors in breast cancer patients. Methods According to the inclusion and exclusion criteria, a total of 2 423 breast cancer patients who underwent breast surgery in the Department of Breast Surgery, Fifth Medical Center, General Hospital of PLA from January 1, 2000 to December 31, 2015 were enrolled for a retrospective study. Kaplan-Meier method and log-rank test were used to compare the 5-year OS and RFS among patients with different clinical stages, molecular subtypes and surgical methods. Cox proportional hazard regression model was used to analyze the influencing factors on the patient survival. Results In 2 423 cases of breast cancer, the median age was 48 years, the median follow-up time was 5.2 years (range: 3.5-18.7 years) and the follow-up rate was 85.3%(2 066/2 423). The 5-year and 10-year OS rate was 91.5% and 84.4% respectively, and the 5-year and 10-year RFS rate (except stage Ⅳ breast cancer) was 85.8% and 78.4% respectively. As for clinical stage, the operable breast cancer accounted for 81.0% (1 963/2 423), local advanced breast cancer 15.6%(378/2 423)and stage Ⅳ breast cancer 3.4%(82/2 423). The 5-year OS rate in stage 0, Ⅰ, Ⅱ, Ⅲ and Ⅳ breast cancer was 100%, 98.5%, 93.8%, 78.1% and 50.8%, respectively, and the 5-year RFS rate (except stage Ⅳ breast cancer) was 98.5%, 95.4%, 87.0% and 63.0%, respectively. Clinical stage was significantly correlated with the 5-year OS and RFS rate of patients (χ2=356.067, 250.433, both P<0.001). As for molecular subtype, except 205 patients with unknown molecular type, the remaining 2 218 patients were divided into luminal, HER-2 overexpression and triple-negative subtypes according to the receptor status, accounting for 72.3%(1 604/2 218), 10.1%(225/2 218) and 17.5%(389/2 218), respectively. The 5-year OS rate of luminal, HER-2 overexpression and triple-negative subtypes was 93.1%, 88.3% and 84.4%, respectively, and the 5-year RFS rate (except stage Ⅳ breast cancer) were 87.7%, 84.8% and 76.7%, respectively. The 5-year OS and RFS rate presented a significant difference across three groups (χ2=24.124, 31.668, both P<0.001). As for surgical methods, the breast-conserving rate was 24.8% (600/2 423) in all patients. In stage Ⅰ breast cancer, the breast-conserving rate was 44.9%(309/688); the breast-conserving surgery group had a higher 5-year OS rate compared with mastectomy group (99.3% vs 98.4%, χ2=6.338, P=0.012); however the 5-year RFS rate showed no significant difference between two groups (96.7% vs 94.8%, χ2=2.245, P=0.134). In stage Ⅱ breast cancer, the breast-conserving rate was 21.1%(237/1 125), the 5-year OS rate in breast-conserving surgery group and mastectomy group was 97.2% and 92.7%, respectively and the 5-year RFS rate was 88.5% and 87.1%, respectively, indicating no significant difference between two groups (χ2=3.793, 1.425; P=0.051, 0.233). Cox proportional hazard regression analysis showed that age, clinical stage and molecular subtype were correlated with the OS of breast cancer patients (HR=1.017, 95%CI: 1.004-1.029, P=0.019; HR=3.242, 95%CI: 2.763-3.803, P<0.001, HR=1.203, 95%CI: 1.066-1.357, P=0.003). Conclusions Age, clinical stage and molecular subtypes are prognostic factors for breast cancer. In stage Ⅰ-Ⅱ breast cancer, the efficacy of breast-conserving surgery is superior to or not worse than mastectomy. Key words: Breast neoplasms; Survival rate; Neoplasm recurrence, local; Breast conserving surgery