IntroductionAdjuvant chemotherapy for breast cancer has undergone a major change over the past two decades. Results from the published update of the overview analysis indicate that administration of adjuvant chemotherapy significantly reduced the risk of recurrence by 23.5% and the risk of death by 15.3%.1 According to the same overview, the 10- year recurrence-free survival for node-positive patients treated with adjuvant chemotherapy was 47.6% for patients younger than 50 years old and 43.6% for those 50 to 69 years old. The 10-year overall survival (OS) was 53.8% and 48.6% respectively.
The recent overview analysis found overall a moderate but highly significant advantage of anthracycline over cyclophosphamide/ methotrexate/5-fluorouracil (5-FL) (CMF) (recurrence rate ratio 0.89 (SE 0.03); breast cancer death ratio 0.84 (SE 0.03)).2 In addition, the allocation of about six months of anthracyclines-based polychemotherapy (e.g. with 5-FL, doxorubicin and cyclophosphamide (FAC) or 5-FL, epirubicin and cyclophosphamide (FEC)) reduces the annual breast cancer death rate by about 38% for women younger than 50 years old when diagnosed and by about 20% for those aged 50 to 69 years old when diagnosed. This is largely irrespective of the use of tamoxifen and of oestrogen receptor status, nodal status or other tumour characteristics. Such regimens are significantly (2p=0.0001 for recurrence, 2p<0.00001 for breast cancer mortality) more effective than CMF chemotherapy.
Two trials provide important confirmatory information regarding the benefit of incorporating four courses of a taxane (paclitaxel) sequentially after four cycles of adjuvant chemotherapy in the adjuvant setting in node-positive patients. Mature results from Cancer and Leukemia Group B (CALGB) 9344 with 69 months of median follow-up demonstrated that the addition of four cycles of paclitaxel given at the dose of 175mg/m2 every three weeks improved recurrence-free survival (reduction in the hazard rate of recurrence, 17%, p=0.0023) and OS (reduction in the hazard rate of death, 18%, p=0.0064).3 The results of the second trial (National Surgical Adjuvant Breast and Bowel Project (NSABP) B-28) have been published very recently.4