Prognostic Value of Pretreatment Neutrophil-to-Lymphocyte Ratio in Osteoradionecrosis
Yoshiaki Tadokoro1, Hasegawa Takumi2, Yuki Murakami2
1Doctor, Division of Immunology, Department of Future Medical Sciences, Kobe University Graduate School of Medicine, Kobe, Japan; Doctor, Department of Oral and Maxillofacial Surgery, Kobe University Graduate School of Medicine, Kobe, Japan.
Background:
Osteoradionecrosis (ORN) is a severe adverse effect of radiation therapy for head and neck cancers. Despite advances in radiation techniques and surgical management, reliable predictors of ORN prognosis remain lacking.
Purpose:
The purpose of this study was to measure the association between systemic inflammatory biomarkers and ORN prognosis.
Study Design, Setting, Sample:
This retrospective cohort study included patients with ORN treated between January 2010 and March 2022 at the Department of Oral and Maxillofacial Surgery, Kobe University Graduate School of Medicine. Patients with unavailable blood test data were excluded.
Predictor Variable:
The predictor variables were pretreatment systemic inflammatory biomarkers, including neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio, and lymphocyte-to-monocyte ratio (LMR). The cutoff values for NLR, platelet-to-lymphocyte ratio, and LMR were determined using receiver operating characteristic curve analysis. Each marker was calculated at the time of diagnosis of ORN.
Main Outcome Variable:
The outcome variable was prognosis. Subjects had a good prognosis if the ORN stage improved. The prognosis was poor if the ORN stage was stable or worse over time.
Covariates:
Sex, age, stage, onset region, primary tumor site, radiation dose, smoking history, medical history, steroid therapy, clinical symptoms, treatment methods, and computed tomography image findings were covariates.
Analyses:
Statistical analysis was performed using Mann-Whitney U nonparametric test, Fisher's exact test, χ2 test, and Cox regression analysis. Statistical significance was set at P < .05.
Results:
The sample consisted of 75 subjects, of whom 16 (21.3%) had a poor prognosis. The median follow-up period was 88 (53 to 122) months. Bivariate analysis revealed that high NLR (P < .01) and low LMR (P = .02) were significantly associated with poor prognosis. In multivariate Cox regression analysis, poor prognosis was significantly associated with advanced age (hazard ratio [HR], 5.33; 95% CI, 1.61 to 17.65; P < .01), ORN stage 3, 4 (HR, 0.18; 95% CI, 0.06 to 0.56; P < .01), high NLR (HR, 14.78; 95% CI, 3.50 to 62.35; P < .01), and periosteal reaction (HR, 19.15; 95% CI, 4.65 to 78.87; P < .01).
Conclusions And Relevance:
We identified high NLR as a risk factor for poor prognosis in ORN. High NLR is considered to reflect worse local tissue and systemic health.
