Triple-negative breast cancer: The effect of guideline-adherent adjuvant treatment on the cumulative survival—A retrospective multicenter cohort study of 3,658 patients.

Abstract

1063 Background: Triple negative breast cancer (TNBC) constitutes an aggressive subtype in breast cancer accompanied with a significant decrease in overall survival (OAS) and disease free survival (RFS). This retrospective cohort study investigates the following queries: (1) Is there an impact of guideline adherent treatment on RFS and OAS in TNBC? (2) Which adjuvant treatment has the most important impact on RFS and OAS in TNBC? Methods: This German multi-center [16 participating hospitals all are certified as breast centers] retrospective cohort study included 3658 patients from 2000 until 2005. The definition of guideline adherence was based on the German national S3 guideline (2004). Results: 371(10.1%) were TNBC [median age(years): 60(range 28-97)]. 13.8% premenopausal/ 9.3% postmenopausal of the patients were TNBC. 90.3% of TNBC-patients were intermediate-/high-risk (Nottingham-prognostic index) and 76.5% were GIII. Compared to HR-pos./HER2-neg.-BC as reference, RFS of TNBC was significantly worse (HR=2.86; 95%CI: 2.17-3.76; p<0.001). Furthermore 5 years RFS (OAS) is significantly lower in TNBC vs. non-TNBC [RFS: 74,8% (95%CI:68.8%-80.8%) vs. 86.5%(95%CI:84.6%-88,4%); logrank p<0.001)] (OAS:75.8%(95%CI:69.9%-81.8%) vs. 86.0%(95%CI:84.1%-87.9%); logrank p<0.001)]. The most important parameters predicting RFS or OAS in TNBC are nodal status, grading, guideline adherent surgery, radiotherapy and chemotherapy. Overall 66.9% TNBC had one or more guideline violations, which subsequently impaired RFS and OAS (Ranking of guideline violations with respect to RFS: Radiotherapy (HR=2.92;95%CI(2.24-3.81); p<0.001), chemotherapy(HR=2.16;95%CI(1.70-2.74); p<0.001), initial surgical intervention(HR=2.03;95%CI(1.36-3.04); p=0.001) and lymph node dissection(HR=1.54;95%CI(1.05-2.25); p=0.027). Conclusions: Patients with TNBC have primarily a worse prognosis in terms of RFS and OAS than patients with primarily non-TNBC phenotype. There is a strong association between guideline adherence and RFS/OAS of patients with TNBC. The outcome decreases significantly with the number of guideline violations.