Hepatocellular carcinoma (HCC) is one of the most frequently encountered malignancies in clinical practice. The pathogenesis underlying HCC is complex, with risk factors exhibiting high heterogeneity across various regions.12 The mortality rate associated with HCC is expected to rise in the next decade13, which poses a serious threat to people's health. Early postoperative HCC recurrence is an important factor affecting the prognosis of patients. A previous study reported that the 5-year recurrence-free survival (RFS) rate following surgical resection of HCC patients is 34.46%.14 It is important to identify the factors influencing early HCC recurrence to construct a predictive model for early diagnosis and treatment to effectively improve the prognosis of patients.
In this study, we found that host-related unfavorable factors (AFP > 400 ng/ml, PLR > 77, AST > 28 U/L, and ALT ≥ 27 U/L) and tumor-related unfavorable factors (tumor diameter ≥ 5 cm, unsmooth margins and satellite nodules) were associated with early recurrence. In particular, a PLR > 77, an unsmooth margin, and satellite nodules are independently associated with early postoperative recurrence in HCC patients.
Host-related risk factors
The platelet-to-lymphocyte ratio (PLR) is a broadly recognized marker of inflammation and immunity that is capable of predicting the prognosis of multiple cancers.15–17 Zheng et al. performed a meta-analysis of 11 cohort studies and reported that a lower PLR is significantly associated with a lower risk of recurrence and higher survival rates after liver resection.18 This finding is consistent with the findings of this study, which indicate that a PLR > 77 is an independent risk factor for early postoperative recurrence in HCC patients. Previous studies have shown that high platelet counts can promote angiogenesis, the production of adhesion molecules, and the formation of an early metastatic niche, thereby further leading to cancer progression.19,20 Lymphocytes are closely related to the body's immune defense. An elevated PLR indicates a high platelet count and low lymphocyte count, which explains the correlation between a high PLR and poor prognosis.
Alpha-fetoprotein (AFP) is a glycoprotein that plays an important role in immune regulation and is crucial for early human development and maintaining immune balance during pregnancy. AFP was first identified in human fetal serum in 1956, and it can serve as a transport protein for multiple ligands, such as bilirubin, fatty acids, and some drugs.21 Our research indicates that an AFP concentration > 400 ng/ml is associated with early recurrence after HCC surgery, but it cannot be considered an independent risk factor. Jung et al. reported the same results.22 A study by Tsilimigras et al. revealed that AFP was an independent risk factor for early postoperative recurrence of HCC.23 This may be attributed to differences in study design and sample size.
Like AFP, the other two factors, aspartate aminotransferase (AST) and alanine aminotransferase (ALT), cannot be regarded as independent risk factors. The results of Zhou et al.’s study indicate that high levels of AST and ALT are risk factors for early recurrence of HCC after surgery but cannot be considered independent predictors, which is consistent with the findings of this study.24 Moreover, a retrospective cohort study by Wei et al. demonstrated that the AST is independently associated with postoperative recurrence of HCC.25 A previous study reported that elevated transaminase levels are significantly associated with Ki-67 immunoexpression, which may be one of the reasons for the early postoperative recurrence of HCC in patients with high AST and ALT levels.26
Tumor-related risk factors
On CT images, the lesion margins are frequently related to the benign or malignant nature of the disease. Currently, few studies have directly linked tumor margins with HCC recurrence. However, the relationship between tumor margins and microvascular invasion (MVI) has been extensively studied, and irregular HCC margins are significantly associated with MVI.27 Since MVI is closely related to early postoperative recurrence22, an unsmooth margin may be associated with early postoperative recurrence of HCC. This study revealed that an unsmooth margin is independently associated with early postoperative recurrence of HCC, which aligns with the findings of Zhang et al.28 Unsmooth tumor margins on CT images may indicate rapid tumor proliferation, which helps explain why HCC with unsmooth margins tends to be more aggressive and more likely to recur.29
The results of this study demonstrated that satellite nodules are another independent risk factor for early postoperative recurrence of HCC. Satellite nodules are often considered tumor nodules formed by the spread of tumor cells from a single primary tumor to the surrounding area, representing intrahepatic metastasis within the venous drainage area around the main tumor.30 Early recurrence is usually the result of metastasis from the resected primary cancer or residual in situ microcarcinomas rather than new cancer development.7,8 Therefore, satellite nodules can predict early recurrence. Previous studies have also proven that satellite nodules are a predictive indicator of early postoperative recurrence of HCC.
Tumor size is the most visually striking morphological feature on CT images and has been widely regarded as one of the most important predictors of tumor recurrence and patient survival.31 The results of this study show that a tumor diameter ≥ 5 cm is associated with early postoperative recurrence of HCC, but its independent predictive role has not been revealed. Lee et al. reported that a maximal tumor size ≥ 3 cm is independently associated with early HCC recurrence.32 The impact of tumor size on recurrence may be related to intrahepatic metastasis and portal vein invasion.33
A logistic regression prediction model
In this study, we constructed a logistic prediction model including the PLR, tumor margins, and satellite nodules through univariate and multivariate logistic regression analyses. The ROC curve for this model was 0.854 (95% CI 0.776 ~ 0.933), and the sensitivity, specificity, PPV, NPV, and accuracy were 85.29%, 92.11%, 78.6%, 80% and 81.8%, respectively. The results of the model are satisfactory. When Logit (P) ≥ 0.449, the likelihood of early postoperative recurrence in HCC patients is high, suggesting that clinicians should comprehensively consider other auxiliary examination results to make individualized treatment decisions and develop reasonable strategies for monitoring for recurrence after resection.
Our study has several limitations. First, this study was an observational and retrospective analysis, so some potential confounders were neglected. Second, this was a single-center study with a small sample size, and prospective studies with larger sample sizes are needed. Finally, the clinical effectiveness of this model in actual applications might be less accurate owing to the limited number of samples.