LAUSR

Dear Editor, We read the recent article published by Kim and colleagues with great interest. 1 The authors stated that they aimed to identify risk factors of HCC recurrence beyondMilan criteria after primary curative liver resection of solitary HCC and solitary HCC initially within Milan criteria. We would like to draw attention to a few points. The authors have reported that they have performed liver resection to 2320 patients with HCC and they have shown that 1308 patients did not develop recurrence and the remaining 1021 patients developed HCC recurrence. In fact, if 1308 is subtracted from 2320, the result is 1012. The authors should explain this calculation that involves difference of 9 patients. Otherwise, the construction of the study design will be faulty starting from the beginning. The flowchart (Fig. 1) and study period presented by the authors in the present study are the same as their study published in Ann. Transl Med, but the numbers are different. 2 If the flowchart in both studies is evaluated, the variables that include the number of patients with HCC recurrence (n = 1021 vs n = 1012), number of excluded patients (n = 429 vs n = 420), recurrent HCC beyond Milan criteria (n = 93 vs n = 77), and recurrent HCC within Milan criteria (n = 499 vs n = 515) were not in accordance. The authors should explain this incompatibility of patient numbers; otherwise, they should state that this is an error. This is important for the accuracy of the statistical analyses they have made. Until the last decade, liver resections involving more ≥ 3 segments were defined as major hepatectomy. 1 The advancements in surgical technique and patient care resulted in a reduction in mortality and morbidity after major hepatectomy. This led to a debate involving the definition of major hepatectomy. Liver resections involving ≥ 4 segments or ≥ 5 segments were suggested to be major hepatectomy after a thorough evaluation of the results of the studies evaluating the morbidity and mortality of the patients after liver resections. 3–5 We have an experience of 5000 major liver surgeries which consist of living donor liver transplantation, living donor hepatectomy, and hepatic resections for benign and liver tumors, and in our opinion, segmental anatomy is not sufficient to define logic of the major hepatectomy. Any liver resection performed for various reasons and technically demanding complex reconstructions such as reconstructions of the portal vein, hepatic vein, hepatic artery, and bile ducts should be considered as major hepatectomy even if two liver segments are resected. Otherwise, we agree with the concept of defining major hepatectomies as any liver resection involving ≥ 4 segments. The analysis of the flowchart suggests that the authors have included patients with solitary recurrence following radical liver resections for HCC. However, in the “Results” section of the article, the median tumor number in the patients with HCC recurrence was reported as 1 (0–20). The aim of the study is analysis of solitary HCC recurrence, and these results are not in accordance with the aim of the study. This point should be explained by the authors. According to the flowchart provided by the authors, the epidemiologic characteristics of this cohort study can be interpreted as follows: (i) the patients with initial beyond Milan (n = 181) have 1.64-fold higher probability of developing solitary HCC recurrence as beyond Milan (n = 39) when compared to the risk of recurrence not being beyond Milan; (ii) the patients with initial beyond Milan (n = 181) have 0.9fold higher probability of developing solitary HCC recurrence as within Milan (n = 142) when compared to the risk of recurrence not being within Milan; (iii) the patients with initial * Sami Akbulut [email protected]