Comparison of a preoperative MR-based recurrence risk score versus the postoperative score and four clinical staging systems in hepatocellular carcinoma: a retrospective cohort study

Abstract

Objectives: To establish a risk score integrating preoperative gadoxetic acid-enhanced magnetic resonance imaging (EOB-MRI) and clinical parameters to predict recurrence after hepatectomy for patients with hepatocellular carcinoma (HCC) and to compare its performance with that of a postoperative score and four clinical staging systems.

Methods: Consecutive patients with surgically confirmed HCC who underwent preoperative EOB-MRI between July 2015 and November 2020 were retrospectively included. Two recurrence risk scores, one incorporating only preoperative variables and the other incorporating all preoperative and postoperative variables, were constructed via Cox regression models.

Results: A total of 214 patients (derivation set, n = 150; test set, n = 64) were included. Six preoperative variables, namely tumor number, infiltrative appearance, corona enhancement, alpha-fetoprotein (AFP) level, aspartate aminotransferase (AST) level, and sex, were independently associated with recurrence. After adding postoperative features, microvascular invasion and tumor differentiation were additional significant variables in lieu of corona enhancement and AFP level. Using the above variables, the preoperative score achieved a C-index of 0.741 on the test set, which was comparable with that of the postoperative score (0.729; p = 0.235). The preoperative score yielded a larger time-dependent area under the receiver operating characteristic curve at 1 year (0.844) than three existing systems (0.734-0.742; p < 0.05 for all). Furthermore, the preoperative score stratified patients into two prognostically distinct risk strata with low and high risks of recurrence (p < 0.001).

Conclusion: The preoperative score integrating EOB-MRI features, AFP and AST levels, and sex improves recurrence risk estimation in HCC.

Key points: • The preoperative risk score incorporating three EOB-MRI findings, AFP and AST levels, and sex achieved comparable performance with that of the postoperative score for predicting recurrence after hepatectomy in patients with HCC. • Two risk strata with low and high risks of recurrence were obtained based on the preoperative score. • The preoperative score may help tailor pretreatment decision-making and facilitate candidate selection for adjuvant clinical trials.

Keywords: Carcinoma, hepatocellular; Gadolinium ethoxybenzyl DTPA; Hepatectomy; Magnetic resonance imaging; Recurrence.

Fig. 1

Flowchart of patient selection. EOB-MRI, gadoxetic acid–enhanced magnetic resonance imaging; HCC, hepatocellular carcinoma; RFA, radiofrequency ablation; TACE, transcatheter arterial chemoembolization

Fig. 2

A The preoperative and postoperative recurrence risk scores for patients with hepatocellular carcinoma after resection; B Definitions and representative images of MRI features included in the established scores; C Probability of 2- and 5-year recurrence-free survival according to the preoperative total risk score; and D Probability of 2- and 5-year recurrence-free survival according to the postoperative total risk score. AFP, alpha-fetoprotein; AST, aspartate aminotransferase; MVI, microvascular invasion; MRI, magnetic resonance imaging; AP, arterial phase; HBP, hepatobiliary phase; RFS, recurrence-free survival

Fig. 3

Time-dependent areas under the receiver operating characteristic curve from 12 to 60 months for proposed scores and staging systems. AJCC, American Joint Committee on Cancer; AUROC, areas under the receiver operating characteristic; BCLC, Barcelona Clinic Liver Cancer; HKLC, Hong Kong Liver Cancer; JIS, Japan Integrated Staging; TNM, tumor-node-metastasis

Fig. 4

Recurrence-free survival curves according to two risk strata defined by the preoperative score