A Systematic Review of the Cost-Effectiveness of Stereotactic Radiation Therapy for Cancer Oligometastases

It is crucial to economically justify the use of promising therapies such as stereotactic ablative radiotherapy (SABR) for oligometastatic disease (OMD). The goal of this systematic review was to provide a summative evaluation of publications that analyzed the cost-effectiveness (CE) of SABR for OMD. Using Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA)-guided methodology, PubMed and Embase were searched for modeling-based CE studies for various forms of limited metastatic disease. Only full publications that specifically compared SABR with a systemic therapy-based approach were included. In total, 9 studies met inclusion criteria; 4 pertained to OMD with mixed histologies, 2 to oligometastatic non-small cell lung cancer, 1 to pulmonary OMD, 1 to liver OMD, and 1 to low-volume oligorecurrent castration-sensitive prostate cancer. All but 1 investigation illustrated that SABR was cost-effective for the studied population (or a subpopulation); of these studies, the incremental CE ratios for SABR (when reported) ranged from $28,000/quality-adjusted life-year (QALY) to $55,000/QALY. Of studies that reported the probability of SABR being cost-effective at common willingness-to-pay values, the median (range) probability of achieving CE was roughly 61% (30%-88%) at a $50,000/QALY threshold and 78% (31%-100%) at a $100,000/QALY threshold. Taken together, the available evidence suggests that SABR appears to be a cost-effective approach for OMD, which has implications for value-based oncologic practice and construction of future health policies. However, reassessment is required in the context of modern systemic therapies (eg, immunotherapy) as well as long-term follow-up of existing and newly reported randomized trials. Prudent patient selection remains the single most important factor influencing the CE of SABR for OMD.