Characterization of pneumonia and other factors leading to poorer survival across all age groups in patients with non-small cell lung cancer (NSCLC)

Abstract

Background: Lung cancer death rates and incidence in both men and women have decreased over the past two decades. However, certain subsets of non-small cell lung cancer (NSCLC) have arisen with poor outcomes. Identifying factors which contribute to poorer outcomes as well as those that inform early detection strategies remain unmet needs. We present data from a contemporaneous group of NSCLC patients that received care at a single University teaching hospital to understand clinical and pathological factors influencing outcomes in the past decade.

Methods: A cohort of 2,289 patients with NSCLC who established care at the Rogel Cancer Center, University of Michigan between January 2011 and April 2019 were identified. Patient characteristics and clinical outcomes were recorded using electronic health records. The Kaplan-Meier method and the Cox proportional model were used to assess relationship between clinic-pathological factors and survival.

Results: Of the 2,289 patients, 92% were >50 years of age while 8% were <50 years of age. The majority (70%) of older patients were former smokers. The majority (61%) of younger patients were diagnosed as having Stage IV NSCLC. Among younger patients, 87% had histologically confirmed non-squamous histology. Univariate analysis revealed that overall survival was significantly lower in patients diagnosed with pneumonia prior to the diagnosis of NSCLC than in those who were not diagnosed with pneumonia (1.9 vs. 21.8 months; P<0.001). Multivariate analysis revealed that older patients had poorer survival than younger patients (HR 1.57, 95% CI: 1.10-2.06, P=0.01) and that patients diagnosed with pneumonia prior to their lung cancer diagnosis had poorer survival across all age groups, particularly in those with advanced-stage disease.

Conclusions: Findings from this study merit prospective studies to understand cost-benefit ratio of follow- up cross sectional imaging of all patients diagnosed with unprovoked pneumonia, including in younger non/current smokers.

Keywords: Non-small cell lung cancer (NSCLC); pneumonia, survival.

Figure 1

Overall survival by pneumonia status. Kaplan-Meier analysis of all patients separated into cohorts based on pneumonia diagnosis. Patients with a pneumonia diagnosis after lung cancer diagnosis (blue line), diagnosis of pneumonia prior to lung cancer diagnosis (red line) and patients diagnosed with lung cancer without a diagnosis of pneumonia (green line). Numbers represent those surviving at each annual time point for each of the cohorts. P<0.001.

Figure 2

Overall survival by age group and pneumonia status. Kaplan-Meier analysis of (A) patients ≤50 years of age stratified by pneumonia diagnosis and (B) patients >50 years of age stratified by pneumonia diagnosis.

Figure 3

Overall survival by stage and pneumonia status. Kaplan-Meier analysis of (A) patients diagnosed with stage I/II NSCLC stratified by pneumonia diagnosis, (B) patients diagnosed with stage III NSCLC stratified by pneumonia diagnosis and (C) patients diagnosed with stage IV NSCLC stratified by pneumonia diagnosis. NSCLC, non-small cell lung cancer.