Regarding "Postresection Period-Specific Hazard of Recurrence as a Framework for Surveillance Strategy in Patients with Hepatocellular Carcinoma: A Multicenter Outcome Study".

We added a comment to the the article by Kim et al.. We first described how the hazard function and commonly used survival function act complementary, although these two functions are mathematically equivalent. Then, we pointed out two notable findings of the present article: 1) a recurrence by metastasis is presumed to occurred constantly at an annualized incidence of 4%-10% until 6 postoperative years; and 2) the annualized recurrence rates between the 5th and 10th postoperative years were between 3%-10% in cirrhotic patients and this figure was comparable to or even lower than the reported annual incidence of HCC in cirrhotic patients (up to 8%). We also pointed out three issues to be paid attention for: 1) the authors amalgamated patients with HBV- and HCV-related HCC together when calculating the hazard function, although the background liver of HCV-related HCC is hypothesized to have a higher carcinogenetic activity than that of HBV-related HCC, at least during the era before the advent of direct-acting antivirals; 2) the authors would have obtained interesting results had they evaluated the risk factors for late-phase recurrence exclusively in patients with HBV infection, including HBV-specific covariates into the analysis; and 3) many investigators may confuse a pathogenic factor with its surrogate marker when interpreting the significance of fibrosis in studies investigating risk factors leading to HCC development.