Tumor volume measured using MR volumetry as a predictor of prognosis after surgical resection of single hepatocellular carcinoma.

Purpose: To evaluate the clinical value of tumor volume-measurement using magnetic resonance (MR) volumetry for predicting prognosis after surgical resection of single small-to-medium-sized hepatocellular carcinoma (HCC) (≤5cm).

Method: This retrospective study included 162 consecutive patients who underwent preoperative gadoxetic acid-enhanced MRI and subsequent surgical resection for single HCC (≤5cm). Tumor volume was measured at hepatobiliary phase of MR images using semi-automated three-dimensional volumetric software program. Recurrence-free survival (RFS) and overall survival (OS) were estimated using Kaplan-Meier method. The Cox-proportional-hazard-model was used to evaluate clinical, pathologic, and radiologic prognostic factors. A minimal p-value approach based on log-rank test statistics was used to obtain the optimal-cutoff tumor volume for predicting RFS and OS. Inter-examiner reproducibility of MR volumetric measurements was assessed using intraclass correlation coefficient (ICC) and coefficient of variance (CV).

Results: After a median follow-up of 84.4 months (range, 2.8-126.5), HCC recurrence occurred in 69 (42.6%) patients and twenty-four (14.8%) patients died with estimated 5-year OS of 90.8%. Larger tumor volume was significantly associated with poor RFS(P = 0.018) and poor OS(P = 0.005) in multivariate analysis. For predicting RFS and OS after surgery, the optimal-cutoff of tumor volume was set at 4.0 mL and 4.0 mL, respectively, with larger volume ≥4.0 mL was significantly associated with poor RFS (hazard ratio[HR], 1.84, P = 0.023) and poor OS (HR, 2.66, P = 0.033). Inter-examiner reproducibility of tumor volume-measurement using MR-volumetry showed ICC of 0.980 and CV of 3.9%.

Conclusions: Tumor volume-measurement using MR-volumetry is clinically feasible and reproducible, and can help predict RFS and OS after resection of single small-to-medium-sized HCC.