Adjuvant chemotherapy for breast cancer: how presentation of recurrence risk influences decision-making

The purpose of this study was to examine the impact of four methods of communicating survival benefits on chemotherapy decisions. We hypothesized that the four methods of communicating mathematically equivalent risk information would lead to different chemotherapy decisions.

Each participant received two hypothetical scenarios regarding their mother (a postmenopausal woman with an invasive, lymph node-negative, hormone receptor-positive breast cancer) and was asked to decide whether they would encourage their mother to take chemotherapy in addition to surgery and tamoxifen. In the part 1, participants received one of four methods of describing the chemotherapy survival benefit: (1) relative risk reduction, (2) absolute risk reduction, (3) absolute survival benefit, or (4) number needed to treat. In part 2, each participant received all four methods. Following each decision, participants were asked to rate their confidence and confusion regarding their decision.

Participants included 203 preclinical medical students. In part 1, participants who received relative risk reduction information were significantly more likely to endorse chemotherapy. In part 2, there were no treatment decision differences when participants received all four methods of communicating survival benefits of chemotherapy. However, receiving all four methods led to significantly higher ratings of confusion. In deciding on endorsing chemotherapy, participants understood the information best when presented with data in the absolute survival benefit format.

These results support the hypothesis that the method used to present information about chemotherapy influences treatment decisions. Absolute survival benefit is the most easily understood method of conveying the information regarding benefit of treatment.