Cost-utility analysis of androgen ablation therapy in metastatic prostate cancer

(Background) As Bayoumi, et al pointed out in their article (J. Natl. Cancer Inst. 2000, vol 92, p 1731), it is evident that treatment of prostate cancer with Luteinizing Hormone Releasing Hormone (LHRH) analogue costs more than treatment by bilateral orchiectomy. However, patients with metastatic prostate cancer are usually treated with LHRH analogue. Does this mean that urologist choose higher cost and less Quality-Adjusted Life Year (QALY) treatment? Therefore, we urologists should re-analyze their conclusion whether the treatment with LHRH analogue is really strictly dominated (high cost and low effect). (Material and Method) We performed a cost-utility analysis using the Markov model based on a formal meta-analysis and literature review, using the same assumptions as Bayoumi, et al, from the perspective of insurer. The base case was assumed to be a 65-year-old man with symptomatic metastatic prostate cancer. The model used time horizon of 10 years. Five androgen ablation therapies were evaluated as first-line therapy: diethylstilbestrol diphosphate (DES), orchiectomy, orchiectomy + nonsteroidal antiandrogen (NSAA), LHRH analogue and LHRH analogue + NSAA. Outcome measures were QALY, lifetime costs and incremental cost-effectiveness ratios. (Results) While DES was the least expensive therapy with the lowest QALY, LHRH analogue monotherapy was the second most expensive therapy with the longest QALY. Incremental cost-effectiveness ratios relative to DES of LHRH (¥4,288,295/QALY) was cheaper than that of orchiectomy when quality of life (QOL) weight of orchiectomy was assumed to be 0.94 relative to that of LHRH analogue. Contrarily, LHRH analogue + NSAA is excluded with strict dominance and Orchiectomy + NSAA is excluded with extended dominance. (Conclusion) Although LHRH analogue costs higher than orchiectomy, LHRH analogue can offer longer QALY than orchiectomy. Cost/QALY of LHRH analogue relative to DES is ¥4,288,295/ QALY, which we considered to represent a good value. Choice of therapy depends on the patient's preference.