Limitations of Nerve Fiber Density as a Prognostic Marker in Predicting Oncological Outcomes in Hepatocellular Carcinoma

SIMPLE SUMMARY: Nerve fibers in the microenvironment have shown notable prognostic potential in various malignancies; however, its role in hepatocellular carcinoma remains to be elucidated. Therefore, the impact of nerve fibers on oncological survival was investigated in a large European cohort of patients with hepatocellular carcinoma who underwent curative-intent liver resection. By means of univariate and multivariate statistics as well as group comparisons of patients with and without nerve fibers, the presence of nerve fibers itself, as well as the corresponding density, was not shown to be associated with survival or the risk of tumor recurrence. Despite being of major prognostic value in various cancer types, nerve fibers in the microenvironment of hepatocellular carcinoma could not be used as a prognostic biomarker in these patients. ABSTRACT: It has been shown that the presence and density of nerve fibers (NFs; NFD) in the tumor microenvironment (TME) may play an important prognostic role in predicting long-term oncological outcomes in various malignancies. However, the role of NFD in the prognosis of hepatocellular carcinoma (HCC) is yet to be explored. To this end, we aimed to investigate the impact of NFs on oncological outcomes in a large European single-center cohort of HCC patients. In total, 153 HCC patients who underwent partial hepatectomy in a curative-intent setting between 2010 and 2021 at our university hospital were included in this study. Group comparisons between patients with and without NFs were conducted and the association of recurrence-free survival (RFS) and overall survival (OS) with the presence of NFs and other clinico-pathological variables were determined by univariate and multivariable Cox regression models. Patients with NFs in the TME presented with a median OS of 66 months (95% CI: 30–102) compared to 42 months (95% CI: 20–63) for patients without NFs (p = 0.804 log-rank). Further, RFS was 26 months (95% CI: 12–40) for patients with NFs compared to 18 months (95% CI: 9–27) for patients without NFs (p = 0.666 log-rank). In a subgroup analysis, patients with NFD ≤ 5 showed a median OS of 54 months (95% CI: 11–97) compared to 48 months (95% CI: 0–106) for the group of patients with NFD > 5 (p = 0.787 log-rank). Correspondingly, the RFS was 26 months (95% CI: 10–42) in patients with NFD ≤ 5 and 29 months (95% CI: 14–44) for the subcohort with NFD > 5 (p = 0.421 log-rank). Further, group comparisons showed no clinico-pathological differences between patients with NFs (n = 76) and without NFs (n = 77) and NFs were not associated with OS (p = 0.806) and RFS (p = 0.322) in our Cox regression models. In contrast to observations in various malignancies, NFs in the TME and NFD are not associated with long-term oncological outcomes in HCC patients undergoing surgery.