Risk factors associated with febrile neutropenia in patients with esophageal cancer receiving 5-fluorouracil plus cisplatin combination chemoradiotherapy.

PURPOSE: To identify risk factors for febrile neutropenia (FN) in patients with esophageal cancer receiving the first cycle of definitive chemoradiotherapy with 5-fluorouracil plus cisplatin and concurrent radiotherapy (FP+R therapy). METHODS: We conducted a retrospective single-center cohort study of patients who started FP+R at Oita University Hospital between April 2011 and June 2023. The primary outcome was FN onset in cycle 1. Univariate tests and multivariable logistic regression [forced entry: age, C-reactive protein (CRP), prognostic nutritional index (PNI), dysphagia] were used to evaluate association with FN development. Receiver operating characteristic (ROC) analysis was conducted to evaluate the predictive performance of baseline CRP for FN. RESULTS: Among 120 patients studied, grade ≥ 3 neutropenia occurred in 37 (30.8%) and FN in 14 (11.7%) during the first cycle. In multivariable analysis, higher baseline CRP was independently associated with increased FN risk [odds ratio (OR) 1.790; 95% confidence interval (CI) 1.120-2.850; p = 0.014], whereas dysphagia showed a non-significant association (OR 2.890; p = 0.145). Age and PNI were not independent predictors. ROC analysis for baseline CRP yielded area under the ROC curve of 0.699 (95% CI 0.520-0.877; p = 0.021) with optimal cut-off value of 0.68 mg/dL (sensitivity 61.54%; specificity 70.65%). CONCLUSION: Baseline systemic inflammation, indicated by elevated CRP, is an independent risk factor for FN development during FP+R therapy. Despite the regimen having an intermediate FN risk, patients with elevated pre-treatment CRP may need closer monitoring. This biomarker may help clinicians perform a more comprehensive risk assessment alongside conventional patient-specific factors.