MRI potentially more cost-effective than CT for imaging liver metastases

Contrast-enhanced MRI is more sensitive than contrast-enhanced CT for diagnosing liver metastases in patients with known colorectal cancer. What’s more, while it’s pricier, the MRI option can also be cost-effective, delivering returns on investment in the form of greater quality-adjusted life years for the patient.

Sopany Saing, MPH, of the University of Technology Sydney and colleagues published the study behind the findings online Oct. 5 in ANZ Journal of Surgery, which is produced by the Royal Australasian College of Surgeons.

For the side-by-side modality analysis, Saing and colleagues constructed an economic decision model linking diagnostic accuracy to health outcomes of colorectal cancer patients.

The model banked on the reasoned assumption that, for this indication, contrast-enhanced (CE) MRI is superior to contrast-enhanced CT on sensitivity and is its equal on specificity.

The model further assumed that these patients could be eligible for curative surgery or chemotherapy and palliation, and that delayed diagnosis or misdiagnosis was associated with worse health outcomes.

The team calculated cost-effectiveness as the incremental cost relative to the incremental benefit, which they estimated using quality-adjusted life years, and they performed sensitivity analyses to test the robustness of the results.

They found that the clinical evidence supports increased sensitivity of CE-MRI compared with CE-CT, 0.943 versus 0.768, respectively—and that CE-MRI was both costlier and more cost-effective than CE-CT.

Saing and colleagues estimated the incremental cost-effectiveness ratio at $40,548 (Australian) per quality-adjusted life year gained, according to their study abstract.

“The model is most sensitive to the cost of MRI, cost of palliative treatment and the disutility”—i.e., the association with worse health outcomes—associated with delayed palliative care, the authors write.

The results were also sensitive to the assumptions made about the clinical algorithm.

“The results provide evidence of the potential cost-effectiveness associated with CE-MRI for the diagnosis of liver metastases in patients with identified colorectal carcinoma,” Saing et al. conclude. “CE-MRI can be recommended as cost-effective provided it replaces CE-CT and that improved diagnostic accuracy results in earlier, curative disease management.”