Apparent diffusion coefficient is a good marker in predicting the prognosis in colorectal cancer liver metastases: a diagnostic study

Background: Colorectal cancer (CRC) is one of the most common malignant tumors. Up to 10% CRC patients can have liver metastases at the first diagnosis. At present, clinical diagnosis of CRC liver metastasis (CRCLM) is mostly based on imaging, and there is a certain false-positive rate and false-negative rate. Improving the diagnostic accuracy of imaging for CRCLM is highly significant. Apparent diffusion coefficients showed high predicting value in other cancers. The aim of the present study was to explore the diagnostic value of apparent diffusion coefficients based on magnetic resonance diffusion weighted imaging for CRCLM.

Methods: Fifty patients with CRCLM admitted to Hebei Yanda Hospital from January 2018 to December 2018 were retrospectively collected, and the data of 50 patients with benign liver nodules were collected at the same time. The diagnostic value of apparent diffusion coefficients on liver metastatic cancer was analyzed using receiver operating characteristic curve. The correlation between apparent diffusion coefficients and clinical pathological features of patients with CRCLM was also analyzed. The diagnosis of liver metastatic cancer was based on pathological biopsy. Three-year follow up after surgery was conducted in clinic or via phone.

Results: Compared with the benign liver nodule group, the apparent diffusion coefficients of patients in the CRCLM group were significantly decreased [(1.14±0.26 vs. 2.06±0.57)×10-3 mm²/s, P<0.001]. The apparent diffusion coefficient was of high value in differentiating between benign liver nodules and liver metastatic cancer. The area under the curve was 0.927 [95% confidence interval (CI): 0.879-0.975, P<0.001]. Compared with patients with highly differentiated tumors, the apparent diffusion coefficients of patients with moderately and poorly differentiated tumors were significantly reduced [(1.08±0.26 vs. 1.29±0.22)×10-3 mm²/s, P=0.010]. Compared with patients who survived 3 years after operation, the apparent diffusion coefficients of patients who died were significantly lower [(1.05±0.26 vs. 1.23±0.23)×10-3 mm²/s, P=0.011]. The apparent diffusion coefficients of liver nodules in patients with CRCLM is a good marker in predicting postoperative 3-year survival, and the area under the curve was 0.728 (95% CI: 0.580-0.876, P=0.006).

Conclusions: The apparent diffusion coefficient can sever as a marker in diagnosing CRCLM and predicting prognosis.