Eliciting preferences for alternative drug therapies in oncology: influence of treatment outcome description, elicitation technique and treatment experience on preferences.

Several methodologic issues arise in eliciting preferences for therapy. Examples are the selection of appropriate descriptions of treatment outcomes and of elicitation techniques. Of particular importance is the correspondence of patients' anticipated preferences for treatment to actual preferences once they have experienced treatment. Treatment outcome descriptions and elicitation techniques were compared for a hypothetical drug decision problem involving trade-offs between quality and quantity of life. Preferences of 54 cancer patients were elicited before, and 6 weeks following initiation of chemotherapy treatment. Patients' preferences were not influenced by the way information about side effects was presented, nor the stated probability of survival at high and moderate levels. A riskless rating technique produced different preferences from those of a risky treatment choice method. Although patients experienced significant toxicity following initiation of treatment, their preferences remained stable on retest. The results raise questions about the extent to which patients are willing, at the time of decision making, to trade off survival rate for improved quality of life.