Background: Response Evaluation Criteria in Solid Tumors (RECIST) criteria are widely used for evaluating the therapeutic effect of colorectal liver metastases (CRLM) patients, but showed undesirable accuracy.
Objective: This study aimed to evaluate the value of functional MRI compared with RECIST criteria in predicting the therapeutic effect in CRLM patients receiving neoadjuvant chemotherapy with and without bevacizumab.
Methods: Overall, 137 patients with CRLM who received neoadjuvant chemotherapy followed by hepatic resection between January 2013 and November 2018 were included and were divided into the bevacizumab and non-bevacizumab groups. Apparent diffusion coefficient (ADC) values of pre- and post-treatment diffusion-weighted imaging (DWI) were generated on the whole-volume (ADCmean), periphery (ADCperi), and isocenter (ADCcentral) of the tumor at the maximum slice. Overall survival (OS) and relapse-free survival (RFS) were used as prognostic indicators.
Results: Post-treatment ADCmean was significantly associated with OS (p = 0.001) and RFS (p = 0.008) in the bevacizumab group, while RECIST-defined response was found to be only significantly associated with RFS in the non-bevacizumab group (p = 0.042). When categorizing the bevacizumab group by the post-treatment ADCmean cut-off value of 1.15 ×10-3 mm2/s, patients in the ADC response group showed significantly better OS than the non-response group (3-year OS: 91.5% vs. 64.5%, p = 0.001). However, no significant difference was found between RECIST-defined response and non-response in either OS (3-year OS: 60.2% vs. 44.0%, p = 0.104) or RFS (3-year RFS: 26.2% vs. 17.4%, p = 0.129) in the bevacizumab group.
Conclusions: DWI-related parameters such as post-treatment ADCmean could accurately reflect the therapeutic effectiveness and predicting survival in patients treated with bevacizumab, which is superior to the RECIST criteria.
© 2021. Society of Surgical Oncology.