Diffusion-weighted MRI beats PET/CT in predicting survival of cancer patients receiving radioembolization

A group of German researchers found diffusion-weighted (DW) MRI provided superior prognostic information compared to PET/CT in liver cancer patients who underwent 90Y radioembolization (RE), and proved more accurate in predicting overall survival in these patients.

Results of the prospective intraindividual study were published online May 22 in Radiology.

“DW MRI seems to be a powerful imaging test that should be used in between lobar 90Y RE treatment sessions, not only to predict response but also to help predict overall survival of patients with liver metastases,” wrote corresponding author Alexandra Barabasch, MD, with the Department of Interventional Radiology at University Hospital RWTH Aachen in Germany, and colleagues.

A total of 36 patients were included in this study. Each had liver-dominant metastases and underwent fluorine 18 fluorodeoxyglucose PET/CT and DW MRI before, and four to six weeks after 90Y RE. All but one patient was observed until death.

Results showed 50 percent of patients responded to PET/CT. Median survival was 39 weeks in those patients compared to 27 weeks in those who did not respond.

In the 67 percent of patients who responded to DW MRI, median survival amounted to 53 weeks compared to 20 weeks for non-responders.

These findings suggest “diffusion-weighted MRI was superior to PET/CT in the prediction of overall survival in patients with liver-dominant hepatic metastatic disease treated with 90Y radioembolization,” authors wrote. Diffusion-weighted MRI also outperformed PET/CT in predicting patient response to radioembolization therapy, Barabasch et al. added.

Additionally, the group found early-response based on diffusion-weighted MRI was the only parameter tested that was associated with overall survival in patients undergoing 90Y RE for liver metastases of solid tumors. 

Despite their findings, Barabasch et al. noted the small cohort sample size was the study’s main limitation, and warned their results “must be interpreted with caution.” They claimed further research must be done with a larger patient cohort to validate their work.