Purpose: To evaluate whether the pretreatment apparent diffusion coefficient (ADC) measured with diffusion weighted imaging (DWI) of tumor can be used as an imaging biomarker for predicting prognosis in solitary large hepatocellular carcinomas (HCCs) treated with transcatheter arterial chemoembolization (TACE) immediately combined with radiofrequency ablation (RFA).
Patients and Methods: In this single institution retrospective study, 40 solitary large HCCs that underwent treatment with TACE immediately combined with RFA were analyzed. All patients underwent abdominal dynamic contrast-enhanced magnetic resonance imaging within one month before treatment with DWI, and ADC values in the lesions were measured by two independent radiologists. Associations among patients’ preoperative ADC values and objective response (OR), progression-free survival (PFS) and overall survival (OS) were examined. Survival curves were drawn with the Kaplan–Meier method, and differences were determined with the Log rank test. The Cox proportional-hazards model was used for univariate and multivariate analyses of PFS and OS.
Results: Forty solitary large HCCs (mean 9.54 cm, range 5.04– 16.06 cm) were successfully treated with TACE in immediate combination with RFA (OR 75%). The ADC values were significantly higher in the response group than the non-response group (1.51± 0.32× 10^{− 3} mm²/s vs 1.09± 0.17× 10^{− 3} mm²/s; P < 0.001). As predicted on the basis of the ADC values, the optimal cutoff value for the efficacy of TACE combined with RFA was 1.32× 10^{− 3} mm²/s, with a predictive sensitivity of 0.63 and a specificity of 1.00. Patients with high ADC had longer PFS than those with low ADC (14.9 months vs 5.3 months; P < 0.001) and had significantly longer survival rates (22.6 months vs 12.1 months; P =0.004).
Conclusion: Preoperative ADC values < 1.32× 10^{− 3} mm²/s are an independent predictor of poorer prognosis in patients with solitary large HCCs who have undergone TACE immediately combined with RFA.
Keywords: solitary large hepatocellular carcinoma, apparent diffusion coefficient, TACE, radiofrequency ablation