Outcome analysis of primary breast cancer patients who declined adjuvant chemotherapy-results from the prospective multi-center BRENDA II study.

ABSTRACT

BACKGROUND: This study examined 5-year overall, recurrence and distant metastasis-free survival (OS, RFS, MFS) of high- and intermediate-risk breast cancer (BC) patients who declined guideline-recommended adjuvant chemotherapy (CHT). METHODS: In the prospective multicenter cohort study BRENDA II, patients with primary BC were sampled over a period of four years (2009-2012). A multi-professional team (tumorboard) discussed recommendation for adjuvant CHT according to the German guideline. Potential differences in 5 year survival were analyzed using Kaplan-Meier curves and Cox regression. The hazard ratios (HR) were adjusted for age, Charlson Comorbidity Score, American Society of Anesthesiologist (ASA) physical status classification, and endocrine therapy. RESULTS: A total of 759 patients were enrolled of which 688 could receive CHT according to the guidelines (n = 219 had a clear indication, in n = 304 it was possible). For 360 patients, the tumorboard advised to perform CHT, for 304 it advised against and in 24 cases, no decision was documented. Of those with a positive suggestion, 83% received CHT. Until 5 years after diagnosis, 57 patients were deceased, 41 had at least one distant metastasis and 29 a recurrence. There was no evidence for differences in OS and MFS in patients who declined CHT despite tumorboard recommendation (HR 3.5, 95% CI 0.8-15.1 for OS, HR 1.9, 95% 0.6-6.6 for MFS). Patients who received CHT had significantly better 5-year RFS compared to those who declined (HR 0.3, 95% CI 0.1-0.9, p = 0.03). There was no evidence for different survival in those who had no CHT because of comorbidity and those who declined actively, neither for OS, MFS nor RFS. CONCLUSION: The prospective BRENDA II study demonstrates benefit in RFS by guideline adherence in adjuvant breast cancer treatment, indicating prospectively the value of internationally validated guidelines in breast cancer care.