Microvascular invasion of single small hepatocellular carcinoma ≤3 cm: Predictors and optimal treatments

BACKGROUND: Small hepatocellular carcinomas (HCC ≤3 cm) are generally considered to have low malignant potential; however, some of them display pathological microvascular invasion (MVI). METHODS: Between 1991 and 2013, 414 patients with a single HCC ≤3 cm underwent curative hepatic resection (HR). Predictors for MVI were identified. Using another cohort (149 patients during 2000‐2014), our predictors for MVI in HCC ≤3 cm were validated. In 428 patients with a single HCC ≤3 cm who had predictors for MVI, survival was compared among anatomical HR (n = 149), partial HR (n = 227), and radiofrequency ablation (RFA) (n = 52). RESULTS: The positive rate of MVI reached 40.6% (168/414 patients). Independent predictors for MVI were as follows: tumor diameter ≥2 cm (odds ratio 1.84, P = .0052), alpha‐fetoprotein (AFP) ≥200 ng/mL (odds ratio 1.82, P = .0466), and des‐gamma‐carboxy prothrombin (DCP) ≥40 mAU/mL (odds ratio 1.79, P = .0126). Matching at least one predictor among these three could predict MVI in HCC ≤3 cm well (sensitivity 82.8%, positive predictive value [PPV] 48.7%). This criterion could also predict MVI in HCC ≤3 cm well in another cohort (sensitivity 82.8%, PPV 30.3%). In patients with single HCC ≤3 cm matching our criterion for predicting MVI, anatomical HR led to significantly better survival in both disease‐free (hazard ratio 0.689, P = .0231) and overall (hazard ratio 0.589, P = .0316) survivals. CONCLUSION: Matching at least one factor among three (tumor diameter ≥2 cm, AFP ≥200 ng/mL, or DCP ≥40 mAU/mL) can predict MVI in HCC ≤3 cm. In such patients, anatomical HR would be recommended to improve survival.