Session Item

The MR-Linac (MRL) is a recent innovation that allows for online re-planning, in order to more accurately deliver radiotherapy to a targeted tumour area. However, MR-guided radiotherapy devices are costly and require adjustments in protocol and personnel compared to regular radiotherapy. In addition, the treatment is a scarce option and thus not available to all patients. Therefore, in this study, an early cost effectiveness analysis on online MR-guided radiotherapy (MRGRT) for colorectal liver metastases is performed, to provide insights in cost-effectiveness potential of MRGRT and, if possible, patient characteristics that would make MRGRT treatment beneficial for some patients.

A Markov-state transition model with 1-year cycles was created to simulate a hypothetical cohort of patients with colorectal liver metastases undergoing MRGRT treatment versus conventional stereotactic body radiation therapy (SBRT) over five years of follow up. Transition probabilities, healthcare costs and utilities were extracted from available literature and Dutch guidelines.  Outcomes were measured in net monetary benefits (NMB) and incremental cost effectiveness ratios (ICER) using quality adjusted life years (QALYs) as effectiveness measurement. Deterministic sensitivity analysis was performed to assess model uncertainties, while scenario analyses were performed to determine the potential health gains MRGRT can bring and thus the parameters suitable for a threshold analysis. Subsequently, threshold analyses were performed to calculate the necessary reductions in toxicity and local recurrence (LR) rate for MRGRT to become cost-effective.

In the model, SBRT treatment resulted in a gain of 2.01 QALYs and 5-year costs of €7082 per patient. MRL treatment resulted in an increase of €6103 in 5-year costs per patient, when no effect in local recurrence, toxicity or survival was assumed. Scenario analysis showed a gain of 0.0017 QALYs (ICER: € 3,574,420) and 0.0034 QALYs (ICER: € 1,787,210) when toxicity rates were halved or completely eliminated, respectively. A gain of 0.1374 QALYs (ICER: € 42,874) and 0.2954 QALYs (ICER: € 18,997) was accomplished when LR rates were halved or completely eliminated, respectively. Threshold analyses of the toxicity and LR rate parameter (Figure 1) show that even complete elimination of toxicity will not make MRGRT a cost-effective treatment. However, MRGRT could become cost-effective if annual LR rates are reduced by 15% or more.

Threshold analyses showed that MRGRT can become a cost-effective alternative to SBRT when LR rates are lowered with 15% compared to those related to SBRT. The effect of toxicity on cost-effectiveness is minimal. MRGRT should be clinically tested and results should be elaborately documented. There is a strong need for extensive follow-up and registration studies to determine favourable patient characteristics for each type of local treatment and to compare these treatments based on their costs and effects.