High preoperative serum LDH level predicted poor DFS in the low-risk subgroups of HCC. The significance of preoperative serum LDH level in predicting DFS in the cohort of HCC patients with AFP ≤ 25 ng/ml (A), with absence of HBsAg (B), with single tumor (C), with tumor size ≤ 5 cm (D), with absence of macrovascular invasion (E), and with TNM stage I to II (F), were estimated by the Kaplan-Meier method and compared by the log-rank test. PVTT, portal vein tumor thrombus.