Long term lung infection surveillance after treatment of lung cancer

Background: Lung cancer patients who have undergone radiotherapy and chemotherapy show an increased risk of infection. The purpose of this study is to investigate the pathogen type, incidence, and associated risk factors of pulmonary infection in patients with lung cancer after treatment. Methods: This cohort study included hospitalized patients who were diagnosed with lung cancer. Patients complain of coughing, dyspnea, fever, chest pain, or hemoptysis lasting more than two weeks (n=801). Data were collected retrospectively from January 2018 to December 2023, with follow-up data extending to July 2024. Findings: Of 801 patients, the median age was 64 (IQR 56-71) years, and 632 (79%) were men. The main pathogens were Mycobacterium tuberculosis (44%), Klebsiella pneumoniae (15%), and Candida albicans (8%). The risk factors of pulmonary infection after treatment of lung cancer were human immunodeficiency virus (Odds Ratio, OR=1.5252 [95% CI 1.0562-2.2024], P=0.0243). Compared with other infectious disease, pulmonary tuberculosis has a higher incidence (Incidence rate ratio, IRR=1.9027 [95% CI 1.5880-2.2859], P<0.0001). Interpretation: Approximately half of admitted patients with symptomatic infection are afflicted with Mycobacterium tuberculosis infection. Despite the diversity of infection, HIV is a risk factor, emphasizing the necessity of raising awareness of infectious diseases in order to improve decision-making about screening, diagnosing, and treating infections in patients with lung cancer.