The presence of comorbidities increased the risk for mortality among patients with lung cancer, particularly among those with localized disease, according to findings from a retrospective study.
Comorbid conditions can worsen lung cancer survival — the 5-year rate of which is only 17% — by complicating diagnostic evaluation and leading to less accurate disease staging, according to study background.
K.M. Monirul Islam, MD, PhD, an assistant professor in the department of epidemiology in the College of Public Health at the University of Nebraska Medical Center, and colleagues conducted this study to assess the individual impact each comorbidity has on survival for patients with lung cancer when controlling for other factors.
The comorbidities analyzed included myocardial infraction, congestive heart failure, peripheral vascular disease, cerebrovascular disease, dementia, chronic pulmonary disease, connective tissue disease, peptic ulcer disease, mild liver disease, diabetes (with and without complications), paraplegia/hemiplegia, renal disease, and moderate or severe liver disease.
The researchers identified 5,683 patients with lung cancer using the Nebraska Cancer Registry between 2005 and 2009. A majority (53.4%) of patients had metastatic lung cancer.
The most common comorbid conditions in the cohort were chronic pulmonary disease (52.5%), diabetes (15.7%) and congestive heart failure (12.9%); however, 26.7% of the patients did not have comorbidities of interest at diagnosis.
Overall, 65.8% of the patients died before the end of the data collection period. A total of 36.8% of patients survived the first year after lung cancer diagnosis and median survival was 9.3 months for all stages combined.
Male sex, as well as small cell, large cell and other cell carcinomas vs. adenocarcinoma were associated with a more advanced-stage diagnosis of lung cancer, whereas squamous cell carcinoma was associated with earlier-stage diagnoses compared with adenocarcinomas (P < .0001).
In analyses adjusted for race, age, histology and sex, patients with comorbid conditions were more likely to be diagnosed at an earlier stage (P < .0001).
Kaplan-Meier survival curves showed comorbidities worsened OS within each stage, particularly among patients with less-advanced stages of lung cancer. In analyses adjusted for age, race, sex and histologic type, the presence of a comorbidity increased the risk for death among patients with localized disease (HR = 1.31), regional disease (HR = 1.22) and distant disease (HR = 1.07).
OS also was negatively associated with comorbidities in analyses adjusted for disease stage. Researchers observed a negative association between localized lung cancer and congestive heart failure (HR = 1.73; 95% CI, 1.33-2.25), diabetes with complications (HR = 2.16; 95% CI, 1.12-4.18) and moderate or severe liver disease (HR = 3.74; 95% CI, 1.09-12.83). Patients with regional disease experienced worse OS when they also had congestive heart failure (HR = 1.26; 95% CI, 1.04-1.52), dementia (HR = 2.33; 95% CI, 1.20-4.52) and renal disease (HR = 1.44; 95% CI, 1.10-1.88). Congestive heart failure (HR = 1.19; 95% CI, 1.05-1.40) and cerebrovascular disease (HR = 1.27; 95% CI, 1.08-1.48) worsened OS among patients with distant disease.
“As the population of the United States ages, there will be a higher number of lung cancer patients with comorbidities at diagnosis,” Islam said in a press release. “We found that lung cancer patients with comorbidities had about a 9-month average survival, which is shorter than the national average. We also found 74% of the patients had one or more comorbidities.
“Our results are based on cancer registry data from one state, so the results may not be generalizable to other populations,” Islam added. “There is a need for a prospective study to confirm these results. We are planning to develop a lung cancer-specific comorbidity index using prospective data for the best estimate of the impact of individual comorbid conditions on survival.” – by Anthony SanFilippo
Disclosure: The researchers report no relevant financial disclosures.