Patient preferences for adjuvant chemotherapy of early breast cancer: how much benefit is needed?

Adjuvant chemotherapy for early-stage breast cancer has been shown to delay recurrence and improve survival. However, the benefits are modest and must be balanced against the adverse treatment effects. We assessed the size of the survival benefit needed to justify the toxicity of chemotherapy, based on the preferences of women who had previously received adjuvant cyclophosphamide, methotrexate, and 5-fluorouracil (CMF). We also attempted to identify circumstances in which larger survival gains would be needed. In semistructured interviews, 104 women who had received adjuvant CMF chemotherapy were asked to rate the survival benefit that would justify 6 months of such treatment, using a series of hypothetical trade-offs between shorter survival without treatment and longer survival with treatment. Similar preferences were sought for a greater probability of 5-year survival. Most patients considered 6 months of adjuvant CMF chemotherapy worthwhile for relatively modest survival gains: 77% considered an increase of from 5 to 6 years worthwhile, 74% thought an increase of from 15 to 17 years worthwhile, and more than 70% considered such treatment justified for a 5% greater chance of living 5 or more years. Smaller survival benefits were needed for women who had experienced less toxicity (P =.01), had not received initial radiotherapy (P =.01), had better social support (P =.02), and had others at home dependent on their support (P =.0001). Modest survival benefits are sufficient to justify adjuvant cytotoxic chemotherapy for most women with early-stage breast cancer. Individual preferences are important when weighing trade-offs between survival and adverse treatment effects.