Anthracycline-based adjuvant chemotherapy in breast cancer.

The publication of the results of the SWOG-8814, INT-0100 trial1 is an important contribution to the controversy around the worth of adding chemotherapy to endocrine therapy in postmenopausal women with hormone-receptor-positive, high-risk breast cancer. Apart from 10% of the patients not completing the planned six cycles of cyclophosphamide, doxorubicin, and fluorouracil (CAF) because of toxicity, the mean doses delivered (as percentages of the planned dose) were 86·6%, 86·1%, and 85·8% during cycles 1–3 for cyclophosphamide, doxorubicin, and fluorouracil, respectively. These mean doses declined during cycles 4–6 to 72·4%, 74·4%, and 71·8% for the three drugs respectively. These results are not surprising because the CAF regimen is complex, long, and moderately toxic. Did Albain and colleagues assess the correlation between reduced dosing of chemotherapy and outcomes?2 This issue is quite relevant for one reason in particular: despite showing overall positive results in favour of chemotherapy, the SWOG-8814, INT-0100 study adds strength to the notion that, for a significant proportion of endocrine-sensitive tumours, chemotherapy might represent unnecessary toxicity.3 However, the effect of suboptimum dosing of chemotherapy, especially in older patients, should be ruled out before this notion can be consolidated. Results of studies using less complex regimens that could be delivered at nearly full doses show signs of efficacy in older patients, irrespective of hormone-receptor status.4 and 5 In endocrine-responsive tumours, which are considered less chemosensitive, one could speculate that suboptimum dosing of chemotherapy might impair efficacy to a greater extent than in chemosensitive tumours. We declare that we have no conflicts of interest.