Implementation of Stereotactic Ablative Radiotherapy for the Treatment of Oligometastatic Cancer in Canada

The aim of this Environmental Scan is to identify and describe the use of stereotactic ablative radiotherapy in Canada, the systems in place to manage the treatment of patients with oligometastatic cancer, and the barriers and facilitators to the implementation of this treatment. The findings are based on a literature review, 22 survey responses from stakeholders, and email- and video call-based follow-up consultations with select stakeholders. Ten Canadian jurisdictions were represented by the survey respondents, who were primarily radiation oncologists. Stereotactic ablative radiotherapy for the treatment of oligometastatic cancer is currently being accessed in all Canadian provinces as a standard treatment option. Centres are primarily treating oligometastases in the lungs, bones (non-spine), lymph nodes, spine, and liver. Some cancer care centres have the capacity for stereotactic ablative radiotherapy to treat localized primary tumours but do not treat oligometastatic sites. There is a variation in patient selection criteria and treatment guidelines across Canadian jurisdictions, with most facilities following institutional guidance for the processes required for patient prioritization and treatment. There is a lack of standardized consensus guidelines with common criteria. Reported facilitators for the implementation of stereotactic ablative radiotherapy for the treatment of oligometastatic cancer include access to dedicated equipment and teams. Reported barriers to its implementation include the lack of standardized patient selection and treatment guidelines, and constraints in equipment and staff resources (including time).

Radiation therapy for oligometastatic cancer

Current approaches to the treatment of patients with metastatic malignant tumors have changed significantly over the past decade. Instead of a purely palliative systemic or just supportive therapy, a large proportion of patients receive an aggressive local treatment directed not only to the primary tumor, but also to metastatic foci, and a number of studies demonstrate the advantage of such approach. This review provides information on the role of radiation therapy as a local method of treatment of cancer patients with oligometastases.

Cost-Effectiveness Analysis of Stereotactic Ablative Body Radiotherapy for the Treatment of Oligometastatic Tumors versus Standard of Care

Background: Recent clinical trial results reported that stereotactic radiotherapy (SABR) may improve survival for patients with oligometastatic (OM) cancer. Given that these results come from a phase II trial, there remains considerable uncertainty about this finding, and about the cost-effectiveness of SABR for patients with OM cancer. In this analysis, we estimate the cost-effectiveness of SABR for oligometastatic cancer patients. Methods: A probabilistic time-dependent Markov model was constructed to simulate treatment of oligometastatic cancer patients over five- and ten-year time horizons. The primary data source was the phase II, Stereotactic Ablative Radiotherapy for the Comprehensive Treatment of Oligometastases (SABR-COMET )trial and supplemented with data from the literature. We estimated the effect of SABR and the standard of care (SoC) using quality-adjusted life-years (QALYs). Costs were measured from a provincial payer perspective (2018 Canadian dollars). Results: In the reference case analysis (five-year time horizon), SABR was associated with additional incremental costs of CAD 38,487 and an incremental QALY gain of 0.84. This resulted in an incremental cost-effectiveness ratio (ICER) of CAD 45,726 per QALY gained. Over a ten-year time horizon, the increased uncertainty in the long-term effectiveness of SABR resulted in an ICER of CAD 291,544 per QALY gained. Estimates from the probabilistic analysis indicated that at a willingness-to-pay (WTP) threshold of CAD 50,000 and CAD 100,000 per QALY gained, there is 54% and 78% probability (respectively) that SABR would be cost-effective using the five-year time horizon. Conclusions: The adoption of SABR therapy requires a considerable upfront capital investment. Our results suggest that the cost-effectiveness of SABR is contingent on the uncertainty in the evidence base. Further clinical trials to confirm the effectiveness of SABR and research into the real-world costs associated with this treatment could reduce the uncertainty around implementation of the technology.