Usefulness of Hounsfield Units and the Serum Neutrophil-to-Lymphocyte Ratio as Prognostic Factors in Patients with Breast Cancer

SIMPLE SUMMARY: Tumor vascularity and immune disturbances are hallmarks of cancer. Targeting agents against them have shown successful results. However, these agents were efficacious regardless of the presence of potential biomarkers. The need to understand this non-specific efficacy led us to focus on the crosstalk between them. We confirmed that each was an independent survival factor by utilizing the tumor-to-aorta ratio (TAR) of Hounsfield units on contrast-enhanced computed tomography and the serum neutrophil-to-lymphocyte ratio (NLR). We found that the survival disadvantage of TAR and NLR manifested only when the other factor was also unfavorable. Finally, we dichotomized patients into two groups, patients with unfavorable features of both TAR and NLR and others without, showing the survival disadvantage of the former group with statistical significance. We believe that this study provides a precise understanding of the crosstalk, with clinical data, promoting a virtual cycle of research from the bed to bench and vice versa. ABSTRACT: Breast cancer is a leading cause of death worldwide. Tumor vascularity and immune disturbances are hallmarks of cancer. This study aimed to investigate the reciprocal effect of tumor vascularity, assessed by the tumor-to-aorta ratio (TAR) of Hounsfield units (HU) on computed tomography (CT), and host immunity, represented by the serum neutrophil-to-lymphocyte ratio (NLR) from peripheral, complete blood cell counts and its impact on patient survival. Female patients with breast cancer who received primary treatment between 2003 and 2018 at Wonju Severance Hospital, Korea, were included. The final cohort included 740 patients with a mean age of 54.3 ± 11.3 (22–89) years. The TAR was 0.347 ± 0.108 (range, 0.062–1.114) and the NLR was 2.29 ± 1.53 (0.61–10.47). The cut-off value for the TAR and NLR were 0.27 and 1.61, respectively. The patients with a TAR > 0.27 showed a poor recurrence free-interval (RFI) only when their NLR was larger than 1.61, and vice versa. The patients showed worse RFI when they had both high TAR and NLR. Our results suggest a dynamic reciprocal communication between tumor vascularity and systemic immunity.