Apparent Diffusion Coefficient Can Predict Response to Chemotherapy of Liver Metastases in Colorectal Cancer

Rationale and Objectives: The aim of this meta-analysis was to evaluate the suitability of apparent diffusion coefficient (ADC) as a predic-tor of response to systemic chemotherapy in patients with metastatic colorectal carcinoma (CRC). Materials and Methods: MEDLINE library, SCOPUS database, and EMBASE database were screened for relationships between pretreat-ment ADC values of hepatic CRC metastases and response to systemic chemotherapy. Overall, five eligible studies were identified. The following data were extracted: authors, year of publication, study design, number of patients, mean value ADC and standard-deviation, measure method, b-values, and Tesla-strength. The methodological quality of every study was checked according to the Quality Assess-ment of Diagnostic Studies-2 instrument. The meta-analysis was undertaken by employing RevMan 5.3 software. DerSimonian and Laird random-effects models with inverse-variance weights were used to account for heterogeneity. Mean ADC values including 95% confi-dence intervals were calculated. Results: Five studies (n = 114 patients) were included. The pretreatment mean ADC in the responder group was 1.15 x 10(-3) mm(2)/s (1.03, 1.28) and 1.37 x 10-3 mm(2)/s (1.3, 1.44) in the nonresponder group. An ADC baseline threshold of 1.2 x 10(-3) mm(2)/s, below which no non -responder was found, can distinguish both groups. Conclusion: The results indicate ADC can serve as a predictor of response to chemotherapy for CRC patients.