Intensity-modulated radiation therapy (IMRT) has been established as the standard external-beam modality in treating low-risk prostate cancer. Stereotactic body radiotherapy (SBRT) is a novel approach involving high-dose radiotherapy in 5 fractions. This analysis compared their cost-effectiveness.
A Markov model was constructed to delineate the health states after treatment with IMRT and SBRT. Disease, treatment, and toxicity data were extracted from the literature. Costs included both robotic (R-SBRT) and nonrobotic (NR-SBRT) reimbursement. Deterministic and probabilistic sensitivity analyses (PSA) were performed over a wide range of potential parameters.
The quality-adjusted life expectancy after IMRT was slightly higher than after SBRT, because we assumed worse toxicity after SBRT. However, the incremental cost-effectiveness ratios (ICER) for IMRT over R-SBRT and NR-SBRT were $285,000 and $591,100/quality-adjusted life year (QALY), respectively. On sensitivity analysis, SBRT was almost always the cost-effective therapy, in which the ICER for IMRT was generally over $100,000/QALY. Reimbursement for R-SBRT versus NR-SBRT significantly influenced its ICER. Treatment efficacy, rectal toxicity and impotence, and the potential for unforeseen SBRT late effects were the most critical parameters in the model; when including these uncertain parameters in a PSA, SBRT was still most likely to be cost-effective at a willingness to pay of $100,000/QALY.
SBRT clearly contained more value than IMRT for external-beam treatment. Given the increasing prevalence of the disease and its superb convenience, intensive research should be performed on this novel modality, including the marginal benefit and cost of robotic treatment.