Nomograms to Predict the Individual Survival of Patients with Solitary Hepatocellular Carcinoma after Hepatectomy

Abstract

Background/aims: Solitary hepatocellular carcinoma (HCC) is a subgroup of HCCs. We aimed to establish nomograms for predicting the survival of solitary HCC patients after hepatectomy.

Methods: A total of 538 solitary HCC patients were randomly classified into training and validation sets. A Cox model was used to identify predictors of overall survival (OS) in the training set. A nomogram was generated based on these predictors and was validated using the validation set.

Results: Tumor size, microvascular invasion, and major vascular invasion were significantly associated with OS in the training set. Nomograms were developed based on these predictors in the multivariate analysis. The C-index was 0.75 for the OS nomogram and 0.72 for the recurrence-free survival nomogram. Compared to the index of conventional staging systems for predicting survival (0.71 for Barcelona Clinic Liver Cancer, 0.66 for the seventh American Joint Committee on Cancer, 0.68 for Cancer of the Liver Italian Program, and 0.70 for Hong Kong Liver Cancer), the index of the OS nomogram was significantly higher. Moreover, the calibration curve fitted well between the predicted and observed survival rate. Similarly, in the validation set, the nomogram discrimination was superior to those of the four staging systems (p<0.001).

Conclusions: The nomograms demonstrated good discrimination performance in predicting 3- and 5-year survival rates for solitary HCCs after hepatectomy.

Keywords: Carcinoma, hepatocellular; Nomograms; Prognosis; Surgery.

Fig. 1

The effect of increasing tumor size on prognosis in a Cox analysis using restricted cubic splines. At the cutoff value of 7 cm, the hazard ratio for the prognosis changed. Solid line indicates the mean value. Dotted line indicates the 95% confidence interval.

Fig. 2

Nomograms for predicting overall survival (OS) (A) and recurrence-free survival (RFS) (B) in hepatocellular carcinoma (HCC) patients after hepatectomy. For each predictor, a straight upward line is drawn to determine the points. The cumulative points are plotted on the total points bar, and a straight downward line shows the 3- and 5-year estimated postoperative survival rates. Microvascular invasion (MVI): 0, none; 1, presence of MVI; Major vascular invasion: 0, none; 1, presence of Major vascular invasion.

Fig. 3

Calibration plots of 3- and 5-year survival rates for the training set (A, B) and validation set (C, D). Nomogram-predicted probability of overall survival is plotted on the X-axis; actual overall survival is plotted on the Y-axis. The gray line indicates the ideal nomogram reference line. Vertical bars represent 95% confidence intervals.

Fig. 4

Kaplan-Meier survival curves of the training and validation sets stratified by the BCLC staging system (A, B), the AJCC seventh edition (C, D), CLIP (E, F), and HKLC (G, H). OS, overall survival; BCLC, Barcelona Clinic Liver Cancer; AJCC, American Joint Committee on Cancer; CLIL, Cancer of the Liver Italian Program; KHLC, Hong Kong Liver Cancer.