Discrete choice experiment to derive willingness to pay for methyl aminolevulinate photodynamic therapy versus simple excision surgery in basal cell carcinoma

Objectives: This study aimed to determine willingness to pay (WTP) and preference for methyl aminolevulinate (MAL) photodynamic therapy compared with simple surgical excision for basal cell carcinoma (BCC). The relative preferences for individual features of the therapy were also determined.

Design: A discrete-choice experiment was conducted to ascertain WTP and relative preferences for treatment of BCC among the general population.

Subjects and methods: Sixty members of the general public (34 men, 26 women; mean age 50 ± 13 years) completed a written questionnaire. Participants indicated their preference between 12 pairs of scenarios representing BCC treatment. The paired scenarios comprised a fixed scenario representing current standard treatment (simple surgical excision) and an alternative scenario. Scenarios comprised five attributes: lesion response rate, risk of scarring, treatment description, possibility of infection and cost. Clinical attributes and levels were derived from clinical trial data. WTP values were in Australian dollars ($A, year 2001 values) and the study was conducted from the societal perspective.

Results: The probability that MAL photodynamic therapy with topical anaesthesia would be accepted in preference to current treatment was 0.879, if there was no cost differential. Total incremental WTP was $A940 for MAL photodynamic therapy. The primary driver of total WTP was reduced risk of scarring, which contributed $A554, but treatment description and infection rate also made significant positive contributions. By contrast, the marginally higher lesion response rate with simple surgical excision (93%) compared with MAL photodynamic therapy (84%) did not significantly reduce WTP. Demographic factors had negligible influence upon the results. Sensitivity analyses indicated that incremental WTP for MAL photodynamic therapy was strongly influenced by the presence of anaesthetic.

Conclusion: There appears to be a sizeable incremental WTP for MAL photodynamic therapy with anaesthetic for the treatment of BCC relative to simple surgical excision, and this is largely driven by better cosmetic outcomes.