Impact on survival of time from definitive surgery to initiation of adjuvant chemotherapy for early-stage breast cancer

Purpose To determine if time to start of adjuvant chemotherapy after curative surgery influences survival in early-stage breast cancer. Patients and Methods A retrospective review was conducted of 2,594 patients receiving adjuvant chemotherapy for stage I and II breast cancer between 1989 and 1998 at the British Columbia Cancer Agency. Relapse-free survival (RFS) and overall survival ( OS) were compared among patients grouped by time from definitive curative surgery to start of adjuvant chemotherapy ( <= 4 weeks, > 4 to 8 weeks, > 8 to 12 weeks, and > 12 to 24 weeks). Results RFS and OS were similar for women starting chemotherapy up to 12 weeks after surgery. OS hazard ratio (univariate) for initiation of chemotherapy more than 12 weeks compared with 12 weeks or less after surgery was 1.5 (95% CI, 1.07 to 2.10; P =.017). Five-year OS rates were 84%, 85%, 89%, and 78%, (log-rank P =.013); RFS rates were 74%, 79%, 82%, and 69% (log-rank P =.004) for patients starting chemotherapy 4 weeks or fewer, more than 4 to 8 weeks, more than 8 to 12 weeks, and more than 12 to 24 weeks after surgery, respectively. In multivariate analysis, independent prognostic factors were grade, size, nodal status, estrogen receptor, age, and lymphatic and/or vascular invasion. Initiation of adjuvant chemotherapy more than 12 weeks from surgery remained significantly associated with inferior survival, with a hazard ratio of 1.6 ( 95% CI, 1.2 to 2.3; P =.005). Conclusion This retrospective analysis suggests that adjuvant chemotherapy is equally effective up to 12 weeks after definitive surgery but that RFS and OS appear to be compromised by delays of more than 12 weeks after definitive surgery.