Variation in type of adjuvant chemotherapy received among patients with stage I breast cancer: A multi-institutional Portuguese cohort study

Background A contemporary US study showed an increase in the use of chemotherapy in the last decade for some patients with stage-I breast cancer; with a rise in more intensive regimens, and declining use of anthracyclines. Nevertheless, there is still uncertainty on the absolute benefit of chemotherapy for these patients and the optimal regimen. In this study we compare those findings with the patterns of care among a Portuguese cohort of stage-I breast cancers. Methods Retrospective cohort study of patients with stage-I breast cancer diagnosed from 2006 to 2008 at four Portuguese institutions. The use and type of chemotherapy was evaluated. Results Among patients with stage I–III breast cancer 39.4% (n = 682) had stage I disease. Of the 595 eligible patients, 22.4% were treated with chemotherapy, 33.9% aged <55 years vs. 12.7% aged >65 years (p < 0.001). Thirteen percent of patients with hormone receptor (HR)+/HER2− tumors, 52.7% of patients with HER2+ and 66.0% of patients with HR-/HER2− received chemotherapy (p < 0.001). In addition, we found inter-institutional variability, with the use of chemotherapy ranging from 0.0% to 43.4% (p < 0.001). Eighty-five percent of patients treated with chemotherapy received less-intensive regimens with anthracycline-based regimens, such as doxorubicin and cyclophosphamide, being the most frequently used, while docetaxel and cyclophosphamide was only used in 1.5% of cases. Conclusions Overall, almost one-quarter of patients received chemotherapy with institutional variability. When treated, mostly less-intensive associations including anthracyclines were used, which contrasts with contemporary US practice. This study highlights the need for health-services research to understand local practices and tailor quality improvement interventions.