Nomogram for Preoperative Estimation of Microvascular Invasion Risk in Hepatitis B Virus–Related Hepatocellular Carcinoma Within the Milan Criteria

IMPORTANCE: The presence of microvascular invasion (MVI) decreases surgical outcomes of hepatocellular carcinoma (HCC). An accurate preoperative prediction of MVI can help surgeons to better choose surgical procedures, but accuracy is still difficult to achieve. OBJECTIVE: 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). DESIGN, SETTING, AND PARTICIPANTS: Data on 1004 consecutive patients who underwent liver resection for HBV-related HCC within the Milan criteria at the Eastern Hepatobiliary Surgery Hospital between April 6, 2004, and February 22, 2011, were prospectively collected. 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. Data analysis was conducted from August 1 to November 11, 2014. EXPOSURES: Liver resection for HCC. MAIN OUTCOMES AND MEASURES: Overall survival and time to recurrence after liver resection were measured. Multivariate logistic regression was used to identify the independent risk factors associated with MVI that then were incorporated into the nomogram. RESULTS: Histopathologically identified MVI was found in 211 of 707 patients (29.8%) and 89 of 297 patients (30.0%) in the training and validation cohorts, respectively. In the training cohort, the 5-year recurrence and overall survival rates were 78.5% and 46.9%, respectively, in patients with MVI and 58.4%, and 70.9%, respectively, in patients without MVI (both P