Diffusion-weighted Magnetic Resonance Imaging for the Prediction and Assessment of Colorectal Liver Metastasis Response to Treatment – a Systematic Review

Purpose: Liver metastases from colorectal cancer can be managed by various treatment protocols. Response assessment to chemotherapy and targeted therapies was historically based on size change, as detailed in the Response Evaluation Criteria in Solid Tumors (RECIST). However, therapy may alter tissue composition and not only tumor size, therefore functional techniques, such as Diffusion-weighted magnetic resonance imaging (DWI), may enhance the response evaluation and prediction. We aimed to systematically evaluate the application of DWI for the prediction and assessment of colorectal liver metastasis response to treatment.

Methods: A search was conducted through MEDLINE/PubMed databases for original publications of DWI for the prediction and assessment of colorectal liver metastasis response to treatment, based on the PRISMA statement. The search included studies published up to September 1, 2021. The risk of bias evaluation included tailored Quality Assessment of Diagnostic Accuracy Studies.

Results: A total of 27 studies were retrieved in the search. Of them, 9 studies met the inclusion criteria. Treatments included chemotherapy (7 studies), radiotherapy (2 studies) and radioembolization (1 study). Different diffusion derived techniques and coefficients were found to be of value to predict and assess response to treatment, however discrepancies were found among the studies.

Conclusions: Diffusion derived techniques and coefficients has the potential to contribute to the evaluation and the prediction of treatment response in colorectal liver metastasis. However, research is currently limited by a small number of mainly retrospective studies; hence, the present published data may not be sufficiently reliable. Prospective controlled studies are needed to further investigate the issue.