CyberKnife for prostate cancer: Is it cost-effective?

Abstract

87 Background: The study assessed the cost-effectiveness of CyberKnife (CK) compared to surgery and radiation therapy for the treatment of prostate cancer (PC) from a third-party and societal perspective. Methods: For patients > 65 yrs with localized PC, a Markov model compared treatment with CK, intensity modulated radiation therapy (IMRT), surgery or proton therapy (PT). Following treatment, patients were at risk of long-term toxicity: genitourinary (GU); gastrointestinal (GI); and sexual dysfunction (SD). Long-term toxicity was defined as adverse events >grade 2 on Radiation Therapy Oncology Group scale occurring at least 12 months following treatment. Markov states included all possible combinations of GI, GU, and SD long-term toxicities, no toxicity, and death. During each year patients remained in the same Markov state or died. Costs and utilities were assigned using published sources. Toxicity probabilities were derived using meta-analytical techniques to pool results from multiple studies. It was assumed that long-term disease control would not differ across treatments. The model projected expected lifetime costs and quality adjusted life years (QALYs) for each treatment and incremental cost-effectiveness of CK vs comparators as cost per QALY gained. Costs from societal perspective included lost productivity. Extensive sensitivity analyses were conducted. Results: Surgery was the least expensive treatment option followed by CK. CK patients had higher expected QALYs (8.11) than other treatment options (7.72- 8.06). From a payer perspective, total lifetime costs were $25,904, $22,295, $38,915, and $58,100 for CK, surgery, IMRT and PT, respectively. Incremental cost per QALY gained for CK versus Surgery was $9,200/QALY. Compared to IMRT and PT, CK was less costly and resulted in higher QALYs (dominance). At a threshold of $50,000/QALY, CK was cost effective in 86%, 79%, and 91% of simulations compared to surgery, IMRT, and PT, respectively. From a societal perspective, CK costs $4,200/QALY compared to surgery and remained dominant vs IMRT and PT. Results were most sensitive to costs of surgery and CK. Conclusions: Initial CK costs are higher than surgery, but CK patients have better quality of life. CK patients have lower lifetime costs and higher QALYs than IMRT and PT patients. [Table: see text]