Preference weights for chemotherapy side effects from the perspective of women with breast cancer.

Perceptions among women with breast cancer about the relative importance of different potential chemotherapy side effects is not well understood. A survey was performed by women receiving chemotherapy for breast cancer. Grade I/II (mild to moderate) and III/IV (moderate to severe) descriptions of nine common chemotherapy side effects were assigned preference weights using the standard gamble technique. For each hypothetical side effect, patients could choose to stay in the respective side effect state or take a gamble between full health (probability p) or being dead (1 - p). For each side effect, p was varied until the patient was indifferent between these options. The survey also included questions about the importance of survival, slowing cancer growth, and quality of life. This analysis included 69 patients; mean age 54 years (range 35-84), representing all cancer stages. Standard gamble preferences were lowest (i.e., least preferred) for grade III/IV nausea/vomiting (0.621), indicating that patients would, on average, risk a 38 % chance of being dead to avoid having grade III/IV nausea/vomiting for the rest of their lives. The next least preferred side effects were grade III/IV diarrhea (0.677) and grade III/IV sensory neuropathy (0.694). Survival appeared more important than slowing cancer growth and maintaining quality of life across cancer stages. Nevertheless, patients with advanced disease placed less importance on survival (p = 0.09) and higher importance on quality of life (p = 0.05). These standard gamble utilities provide unique insights into chemotherapy toxicities from the patient perspective. Differences in the relative importance of overall survival and quality of life with treatment existed between patients with different stages of disease. These studies should be expanded as the data may also be used to calculate quality-adjusted life expectancy in cost-effectiveness evaluations of breast cancer chemotherapies.