Nomogram for Preoperative Estimation of Microvascular Invasion Risk in Hepatitis B Virus-Related Hepatocellular Carcinoma Within the Milan Criteria.IMPORTANCE
 To develop a nomogram to predict MVI presence before liver resection for hepatitis B virus (HBV)-related HCC within the Milan criteria (solitary nodule ≤5 cm; ≤3 nodules, none >3 cm; and no macrovascular invasion).


 Of these, patients who underwent surgery in an earlier period formed the training cohort (n = 707) for nomogram development, and those who underwent surgery thereafter formed the validation cohort (n = 297) to confirm the model's performance.  Multivariate logistic regression was used to identify the independent risk factors associated with MVI that then were incorporated into the nomogram.


 Incorporating these 7 factors, the nomogram achieved good concordance indexes of 0.81 (95% CI, 0.78-0.85) and 0.80 (95% CI, 0.75-0.86) in predicting MVI in the training and validation cohorts, respectively, and had well-fitted calibration curves.  The positive and negative predictive values (95% CIs) of the nomogram were calculated, resulting in positive predictive values of 57.2% (52.0%-64.9%) and 57.9% (49.2%-68.5%) and negative predictive values of 87.2% (83.2%-89.4%) and 83.2% (76.0%-87.7%) for the training and validation cohorts, respectively.  Patients who had a nomogram score of less than 200 or 200 or greater were considered to have low or high risks of MVI presence, respectively.


 The nomogram achieved an optimal preoperative prediction of MVI in HBV-related HCC within the Milan criteria. 
Nomogram