The Inter-Relationships Among the Risk Factors for Pulmonary Infection and the Diagnostic Utility of Inflammatory Markers in Patients with Non-Small Cell Lung Cancer

Abstract

Objective: To analyze independent risk factors and the distribution of pathogenic bacteria associated with pulmonary infection (PI) in patients with non-small cell lung cancer (NSCLC); and to explore the utility of peripheral blood-related inflammatory markers in the diagnosis of PI after comprehensive treatment of NSCLC. Methodology: We retrospectively analyzed patients who were first diagnosed with NSCLC and received anti-tumor therapy from January 1, 2022 to December 31, 2022. There were 150 males and 50 females enrolled, and with a median age of 63 years. They were divided into PI (n=59) and non-PI (n=141) groups. The patients’ characteristics, treatment histories, and peripheral blood inflammatory indicators of the two groups were compared. Results: Eighty-two strains of pathogens were isolated from 59 patients with NSCLC complicated by PI, of which 35 (42.7%) were Gram-negative and 29 (35.4%) were Gram-positive bacteria, 15 (18.3%) were fungi, and 3 (3.7%) were viruses. Logistic regression analysis revealed that ≥ 4 cycles of chemotherapy, radiotherapy, and higher neutrophil count before antineoplastic treatment were independent risk factors for PI in patients with NSCLC (P<0.05). C-reactive protein (CRP) and CRP-to-albumin ratio (CAR) exhibited high area under the curve values of 0.807 and 0.791, respectively. CRP demonstrated high sensitivity (Cutoff Value:10.095, P<0.001), whereas CAR had high specificity (Cutoff Value:0.747, P<0.001) for the early diagnosis of PI in patients with NSCLC. Conclusion: Gram-negative bacteria were the main pathogens causing PI in patients with NSCLC. Greater than or equal to 4 cycles of chemotherapy, radiotherapy, and elevated neutrophil count before antineoplastic treatment were independent risk factors for PI in patients with NSCLC. Elevated CRP levels and higher CAR demonstrated a certain diagnostic utility for PI in patients with NSCLC after antitumor treatment.