Oncological outcomes of anatomic versus non-anatomic resections for small hepatocellular carcinoma: systematic review and meta-analysis of propensity-score matched studies

BACKGROUND: Primary liver cancer is the second-most commonly occurring cancer and has resulted in numerous deaths worldwide. Hepatic resection is of two main types, i.e., anatomic resection (AR) and non-anatomic resection (NAR). The oncological outcomes of hepatocellular carcinoma (HCC) patients after AR and NAR are still considered controversial. Therefore, we aimed to compare the impact of AR and NAR on the oncological outcomes of HCC patients with tumor diameters ≤ 5 cm using the propensity score matching method and research-based evidence. METHOD: A systematic literature search was conducted. The main outcomes were disease-free survival (DFS), overall survival (OS), intrahepatic recurrence rate, and extrahepatic metastasis rate. Relative risk (RR) was calculated from forest plots and outcomes using random-effects model (REM). RESULT: AR significantly improved DFS at 1, 3. and 5 years after surgery, compared to NAR (RR = 1.09, 95% CI = 1.04–1.15, P = 0.0003; RR = 1.16, 95% CI = 1.07–1.27, P = 0.0005; RR = 1.29, 95% CI = 1.07–1.55, P = 0.008). However, both of the difference in DFS at 7 years and OS at 1 and 3 years after AR versus that after NAR were not statistically significant. Nevertheless, the long-term OS associated with AR (5, 7, and 10 years) was superior to that associated with NAR (RR = 1.12, 95% CI = 1.03–1.21, P = 0.01; RR = 1.19, 95% CI = 1.04–1.36, P = 0.01; RR = 1.18, 95% CI = 1.05–1.34, P = 0.008). The difference in the intrahepatic recurrence rate after AR versus that after NAR was not statistically significant, but the extrahepatic metastasis rate after AR was significantly lower than that observed after NAR (RR = 0.61, 95% CI = 0.40–0.94, P = 0.03). CONCLUSION: Therefore, AR should be the preferred surgical approach for HCC patients with tumor diameters ≤ 5 cm. TRIAL REGISTRATION: PROSPERO registration number CRD42022330596.