Anthracycline and concurrent radiotherapy as adjuvant treatment of operable breast cancer: a retrospective cohort study in a single institution

BACKGROUND: Concurrent chemoradiotherapy (CCRT) after breast surgery was investigated by few authors and remains controversial, because of concerns of toxicity with taxanes/anthracyclines and radiation. This treatment is not standard and is more commonly used for locally advanced breast cancer. The aim of our study was to evaluate the efficacy and safety of the concomitant use of anthracycline with radiotherapy (RT). FINDINGS: Four hundred women having operable breast cancer, treated by adjuvant chemotherapy (CT) and RT in concomitant way between January 2001 and December 2003, were included in this retrospective cohort study. The study compares 2 adjuvant treatments using CCRT, the first with anthracycline (group A) and the second with CMF (group B). The CT treatment was repeated every 21 days for 6 courses and the total delivered dose of RT was 50 Gy, divided as 2 Gy daily fractions. Locoregional recurrence free (LRFS), event free (EFS), and overall survivals (OS) were estimated by the Kaplan-Meier method. The log-rank test was used to compare survival events. Multivariate Cox-regression was used to evaluate the relationship between patient characteristics, treatment and survival. In the 2 groups (A+B) (n = 400; 249 in group A and 151 in group B), the median follow-up period was 74.5 months. At 5 years, the isolated LRFS was significantly higher in group A compared to group B (98.7% vs 95.3%; hazard ratio [HR] = 0.258; 95% CI, 0.067 to 0.997; log-rank P = .034). In addition, the use of anthracycline regimens was associated with a higher rate of 5 years EFS (80.4% vs 75.1%; HR = 0.665; 95% CI, 0.455 to 1.016; log-rank P = .057). The 5 years OS was 83.2% and 79.2% in the anthracycline and CMF groups, respectively (HR = 0.708; 95% CI, 0.455 to 1.128; log-rank P = .143). Multivariate analysis confirmed the positive effect of anthracycline regimens on LRFS (HR = 0.347; 95% CI, 0.114 to 1.053; log-rank P = .062), EFS (HR = 0.539; 95% CI, 0.344 to 0.846; P = 0.012), and OS (HR = 0.63; 95% CI, 0.401 to 0.991; P = .046). LRFS, EFS and OS were significantly higher in the anthracycline group where the patients (n = 288) received more than 1 cycle of concurrent CT (P = .038, P = .026 and P = .038, respectively). LRFS and EFS were significantly higher in the anthracycline group within the BCT subgroup (P = .049 and P = .04, respectively). There were more hematologic, and more grade 2/3/4 skin toxicity in the anthracycline group. CONCLUSIONS: After mastectomy or BCT, the adjuvant treatment based on anthracycline and concurrent RT reduced breast cancer relapse rate, and significantly improved LRFS, EFS and OS in the patients receiving more than 1 cycle of concurrent CT. There were more hematologic and non hematologic toxicities in the anthracycline group.