Patient preferences for chemotherapies used in breast cancer

Abstract

Background: Therapies for invasive breast cancer may be associated with an incremental survival advantage that should be weighed against the risk of toxicities when making treatment decisions. The objective of this study was to elicit patient preferences for a comprehensive profile of attributes associated with chemotherapies for breast cancer.

Methods: This was a cross-sectional study of 121 patients with stage I-IV breast cancer who completed an internet-based conjoint survey that assessed the following attributes: ten grade III/IV toxicities, survival advantage, and administration regimen. Literature and expert input were used to identify descriptions for each attribute and respective levels (eg, different risks of toxicities). Subjects rated the attribute levels on a series of scales and indicated preferences in pair-wise comparisons of two hypothetical treatments differing in attribute levels. Ordinary least-squares regression was used to calculate utilities (preference weights) for each attribute level.

Results: Of the twelve attributes, survival was the most important; specifically, a survival advantage of 3 months versus no survival advantage was most influential in the perceived value of chemotherapy. Among toxicities, the differences in the risks of neutropenia with hospitalization, diarrhea, nausea, and fatigue had the most impact on preferences; the risk differences of myalgia, stomatitis, and hand-foot syndrome had the least. In general, a more convenient administration regimen was less important than a 13% chance or more of severe toxicities, but more important than a 10%-12% chance of severe toxicities.

Conclusion: Breast cancer patients place high value on small incremental survival advantages associated with treatment despite the risk of serious toxicities.

Keywords: breast cancer; chemotherapy; conjoint; preferences; toxicity.

Figure 1

Relative importance of attributes*. Note: *Ratio data: 10% is twice as important as 5%.

Figure 2

Percentages of patients preferring treatment given a 0% chance of the selected toxicity versus a 10% chance, holding all other attributes constant.

Figure 3

Percentages of patients preferring treatments with differences in survival advantage and differences in regimen convenience, holding all other attributes constant.