Taxanes in the treatment of breast cancer: Have we better defined their role in older patients? A position paper from a SIOG Task Force

• Numbers of elderly breast cancer patients are rising and require optimum therapy.
• Taxanes are highly active but use needs to be tailored to frailty and comorbidity.
• Toxicity limits adjuvant use with anthracyclines to high risk, healthy patients.
• Given anthracycline cardiotoxicity, taxane regimens are an alternative.
• For metastases, weekly paclitaxel and q3w docetaxel (75 mg/m2) are key options.

Along with anthracyclines, taxanes are the most active cytotoxics in breast cancer (BC). Balancing efficacy against toxicity in older patients with reduced physiological reserves and significant comorbidities is both important and difficult. This is especially so given the under-representation of elderly patients in major trials and a consequent lack of evidence for drug, dose and schedule. However, BC is frequent in elderly women, who are a growing proportion of the population. Careful consideration of their care is therefore imperative. Treatment that can cure or extend the duration and quality of life should not be restricted by age, but needs to be tailored to the circumstances of elderly patients. In adjuvant use, taxane toxicity in older women is greater than in their younger counterparts, limiting its sequential combination with anthracyclines for high-risk disease unless patients are in very good health. More frequently taxanes are used alone (weekly paclitaxel, three-weekly docetaxel) or combined with cytotoxics other than anthracyclines (e.g. docetaxel plus cyclophosphamide) to reduce cardiac risk, especially in HER-2-positive patients who may develop additional trastuzumab-related cardiac events. In elderly patients with metastases, weekly paclitaxel and three-weekly docetaxel are among the cornerstones of treatment, with generally acceptable toxicity. Three-weekly docetaxel at the approved dose of 100 mg/m2 is not appropriate for the elderly. Nab-paclitaxel has efficacy comparable with solvent-based taxanes without need for steroid premedication but has been little studied in older BC patients. A head-to-head comparison with weekly paclitaxel favoured the solvent-free formulation for pathologic response, but those studied were a general adult population. Compared with early stage disease, choice of taxane and regimen in the metastatic setting relies even more on availability and preferences with regard to schedule, toxicity profile and cost, especially for recently developed formulations.