Prognostic value of ADC measurements in predicting overall survival in patients undergoing 90 Y radioembolization for colorectal cancer liver metastases.

AIM: To assess the ability of diffusion-weighted imaging (DWI) in predicting the overall survival in patients who underwent Yttrium 90 radioembolization (90 Y-RE) for colorectal liver metastases (CLM) with other well-established clinical and imaging parameters by comparing the pre- and post-treatment apparent diffusion coefficient (ADC) values of the lesions.

METHODS: A total of 81 metastatic lesions of 27 consecutive patients who underwent DWI before and after the 90 Y-RE session were enrolled in the study. ADC values were calculated from the entire (ADCe ) and peripheral (ADCp ) tumor on pre- and post-treatment DWI, and any relative increase in ADC >0% accepted as a functional imaging response. The impact of functional imaging response in addition to other well-known parameters including Response Evaluation Criteria in Solid Tumors (RECIST), hepatic tumor burden, Eastern Cooperative Oncology Group performance status (ECOG-PS) and the presence of extrahepatic metastases in predicting overall survival (OS) was assessed using Kaplan-Meier curves and Cox-regression analyses.

RESULTS: The median OS of the patients was 10 months (range, 6-20 months) while the median OS of the responders being significantly longer than the non-responders for ADCe and ADCp (median 11 vs 7 months, P = 0.003; median 12 vs. 7 months, P < 0.0001, respectively). The RECIST score was also significantly affected the OS (progressive or stable disease median 8 months vs. partial response 15 indent months, P = 0.019). The other parameters including hepatic tumor burden, gender, ECOG score, the involvement of the liver lobes, and the presence of extrahepatic metastases were not associated with the OS. In multivariate analysis, only ADCp remained as an independent predictor of OS (P = 0.003, HR = 19.878).

CONCLUSION: Any increase in relative ADCp or ADCe values after Y90-RE treatment was associated with longer OS in CLM patients, and DWI seems to be valuable imaging biomarker in predicting OS in CLM patients during the early post-interventional period after 90 Y-RE.