Hydrogel rectal spacer SpaceOAR™ in prostate cancer radiation therapy - Health economic evaluation
Health technology assessment
|Published
We were commissioned to perform a health technology assessment of SpaceOAR™ hydrogel for prevention of radiation-induced side effects following treatment for prostate cancer.
Key message
The National System for Managed Introduction of New Health Technologies within the Specialist Health Service in Norway (“Nye Metoder”) commissioned the Norwegian Institute of Public Health to perform a health technology assessment of SpaceOAR™ hydrogel for prevention of radiation-induced side effects following treatment for prostate cancer. Efficacy and safety of the intervention are addressed in a recent EUnetHTA report published in July 2020 (1). This report assesses the technology in light of the Norwegian priority setting criteria (health benefits, resource use and disease severity). Health benefits and disease severity are expressed in quality adjusted life years (QALYs).
Key findings:
- Absolute shortfall for patients suffering from radiation-induced adverse events is 1.85 QALYs.
- The cost-utility analysis indicated that SpaceOAR™ in combination with radiation therapy was more costly (incremental costs: 15,330 NOK) and slightly more effective (incremental effects: 0.008 QALYs) than radiation therapy alone.
- The health benefit of the intervention is very uncertain. Our analysis indicates that the intervention only has a 59% likelihood of generating a net health benefit as measured in QALYs.
- The incremental cost-effectiveness ratio (ICER) is NOK 2,006,985 per QALY.
- The results of sensitivity analysis indicated that the price of the spacer, the quality of life weights and the efficacy of the treatment have the greatest impact on the results.
The budget impact analysis indicated that costs of the intervention would be approximately 15 million NOK per year.
Summary
Background
Radiation therapy is the most common treatment for prostate cancer. Dose-escalated external beam radiation provides better disease control, but also increases the chances for developing radiation-induced gastrointestinal and genitourinary toxicities. Hydrogel rectal spacer SpaceOAR™ is a medical device intended to reduce harm from the radiation therapy by increasing the space between the rectum and the prostate.
Decisions to introduce new technologies within the Norwegian Specialist Health Services are informed by three primary criteria for setting health care priorities in Norway: the benefit criterion, the resource criterion, and the severity criterion (2). The benefit criterion refers to a technology’s expected health effects: increased longevity and/or improved health-related quality of life, measured in quality adjusted life years (QALY). According to the benefit criterion, priority increases with the size of the expected benefit of the intervention. According to the resource criterion, priority increases, as fewer resources are needed for the intervention. According to the severity criterion, priority increases with expected future health loss resulting from the disease. Severity of disease is measured as “absolute shortfall”, defined as the expected loss of future health (QALYs) associated with a specified diagnosis. For treatment of a diagnosed disease, severity is the average expected absolute shortfall for the relevant patient group given the current standard treatment.
In practice, the three priority setting criteria are taken into account by weighing costs against benefits in a cost-effectiveness analysis of the technology of interest relative to a comparator. The result is reported as a cost-effectiveness ratio in which the numerator captures incremental resource use, measured in monetary terms, while the denominator reflects the incremental health effect measured in QALYs. Different levels of disease severity and associated threshold values for cost-effectiveness is outlined in health policy documents (report from the Magnussen group, https://www.regjeringen.no/no/dokumenter/pa-ramme-alvor/id2460080/ ), although an official cost-effectiveness threshold does not currently exist in Norway.
Objective
The objective of this report is to assess the cost-effectiveness and budget impact of the hydrogel rectal spacer SpaceOAR™ for the prevention of radiation induced harm in patients with prostate cancer in Norway.
Method
In order to evaluate the cost-effectiveness of SpaceOAR™, we developed a health economic model consisting of a decision tree and a state-transition Markov model. We calculated the severity of disease, measured as absolute shortfall, by subtracting the model predicted prognosis of patients receiving current treatment from the age adjusted number of remaining quality adjusted life years, as recommended for priority setting in Norway. The cost-effectiveness analysis compares the incremental costs expressed in 2020 Norwegian kroner (NOK) and health effects as measured in quality adjusted life years (QALYs) of the device in combination with the radiation therapy with radiation therapy alone. The analysis applies a ten-year time horizon and a broad healthcare perspective on costs, as recommended in Norwegian guidelines. Data on the efficacy and safety of SpaceOAR™ were collected from a 2020 EUnetHTA report (1). A Norwegian summary of this EUnetHTA report is included in the appendix 14. We discounted costs and health effects using an annual discount rate of 4%. The results were expressed as incremental cost-effectiveness ratio (ICER), i.e. expected incremental costs (NOK) per unit of health gain (QALY). We performed on-way sensitivity analyses and a probabilistic sensitivity analysis. To estimate the financial consequences of implementing the device in health care practice, we conducted a budget impact analysis.
Results
The estimated absolute shortfall for patients suffering from the radiation-induced adverse events was 1.85 QALYs, which places it in the least severe of the six classes suggested by the Magnussen group (https://www.regjeringen.no/no/dokumenter/pa-ramme-alvor/id2460080/). We find SpaceOAR™ to be more costly (incremental costs: 15,330 NOK) and slightly more effective (incremental effects: 0.008 QALYs) than radiation therapy alone. The resulting incremental cost-effectiveness ratio (ICER) is 2,006,985 NOK/QALY. Note that the high ICER is a result of the very modest health gain achieved by the intervention. The results of sensitivity analysis illustrated that the price of the spacer, the quality of life weights and the efficacy of the intervention had the greatest impact on the results.
The probabilistic sensitivity analysis indicates that the health benefit of the intervention is very uncertain, with only 59% of simulations resulting in a net health gain as measured in QALYs. There is however 100% certainty that the spacer will increase costs. The budget impact analysis indicated that adoption of hydrogel rectal spacer would increase spending by approximately 15 million NOK per year.
Discussion
EUnetHTA’s relative effectiveness assessment included two studies: one RCT on SpaceOAR™ with companion studies (3–6) and one non-RCT (7).
Further research may change the conclusion of this analysis. Notably, the documentation on the efficacy of hydrogel rectal spacer is uncertain, the cost-effectiveness analysis should be updated if or when more documentation becomes available. In addition, the cost effectiveness analysis would benefit from more studies on the natural history of the disease, i.e. duration of radiation induced toxicities, the incidence rate of such toxicities and the percentage of patients who would experience a resolution of their symptoms.
Bases on current evidence, it seems unlikely that SpaceOAR™ will be considered a high priority technology for adoption in routine public financing. The analysis would need to be updated if or when new evidence becomes available and the conclusions may thus change.
Conclusion
This report has assessed to what degree the technology meets the Norwegian priority setting criteria (health benefits, resource use and disease severity). The absolute shortfall is 1.85 QALY, placing the disease in the lowest priority setting group following the approach suggested by the Magnussen group (https://www.regjeringen.no/no/dokumenter/pa-ramme-alvor/id2460080/ ). The health benefit of the intervention is small (0.008 QALYs) and very uncertain.
