Evaluation of infections in non-small cell lung cancer patients treated with radiotherapy

Abstract

Purpose: We aim to determine infections occuring in patients with non-small cell lung cancer during radiotherapy (RT). Methods and materials: A total of 181 patients had been treated with thoracic radiotherapy between October 1995 and December 1999. Radiotherapy was given using 1.8-3 Gray (Gy) fraction daily, five fractions a week for a total dose of 59.4 Gy (30-70.2 Gy). A complete history was collected retrospectively for each patient. All microbiological examinations were performed according to the routine procedures of the hospital laboratory. Numeric and categoric variables were employed such as sex, age, performance status, histology, stage, chemotherapy, usage of corticosteroids, neutropenia, surgery, hospitalization, associated diseases, smoking during treatment, package per year of cigarette smoking, dose of radiotherapy, and response rates. Results: Infections developed in 84 patients (46%, 84/181) during thoracic radiotherapy. A 101 episodes of infections developed in these patients. Most patients suffered from sputum production (65%), cough (59%), auscultation findings (31%) and fever (31%). Gram-negative bacteria were the most frequently isolated pathogens in the cultures of specimens (70%, 16/23 samples). Neoadjuvant chemotherapy (OR = 4.81; 95% CI, 1.57-9.12; p = 0.003) and neutropenia (OR = 4.25; 95% CI, 1.44-6.89; p = 0.009) were found as risk factors for influencing infection based on logistic regression analyses. Package per year of cigarette smoking was found statistically significantly higher in patients with infections than patients without infections (p = 0.001). A slight increase in infections, which was of borderline statistical significance (p = 0.07), was observed in patients age over 70. Ciprofloxacin and clarithromycin were the most frequently used agents in treatment. Median survival was 9 months in the patients with infection and 13 months in the 97 patients without infection. Overall survival seemed to be statistically significantly better in patients without infection than patients with infection (p = 0.042) calculated using Kaplan-Meier method. Based on Cox regression analyses; overall survival was not correlated to presence of infection but associated with poor performance status (<= 80) (OR = 2.35; 95% CI, 0.85-8.93; p = 0.03), and usage of corticosteroids (OR=2.68; 95% CI, 0.98-6.72; p = 0.01). The dose of radiation therapy > 5940 cGy (OR = 2.06; 95% CI, 0.72-7.18; p = 0.007) and the absence of response to treatment (OR = 2.45; 95% CI, 0.89-14.23; p < 0.001) were also found to be risk factors for survival. Conclusions: Infections are important causes of morbidity and mortality in lung cancer patients. The control of infection in these patients may improve the survival. Predisposing factors and treatment management approaches in non-small cell lung cancer should be defined carefully.