Survival among Never-Smokers with Lung Cancer in the Cancer Care Outcomes Research and Surveillance Study.

RATIONALE

Differences in patient characteristics and outcomes have been observed among current, former, and never-smokers with lung cancer, but most prior studies included few never-smokers and were not prospective.

OBJECTIVES

We used data from a large, prospective study of lung cancer care and outcomes in the United States to compare characteristics of never-smokers and smokers with lung cancer and to examine survival among the never-smokers.

METHODS

Smoking status at diagnosis was determined by self-report and survival was determined from medical records and cancer registries, with follow-up through June 2010 or later. Cox regression was used to examine the association between smoking and survival, and to identify predictors of survival among never-smokers.

MEASUREMENTS AND MAIN RESULTS

Among 3,410 patients with lung cancer diagnosed between September 1, 2003 and October 14, 2005 who completed a baseline patient survey, there were 274 never-smokers (8%), 1,612 former smokers (47%), 1,496 current smokers or smokers who quit recently (44%), and 28 with missing information about smoking status (<1%). Never-smokers appeared more likely than former and current/recent smokers to be female and of Asian or Hispanic race/ethnicity, and to have adenocarcinoma histology, fewer comorbidities, private insurance, and higher income and education. Compared with never-smokers, the adjusted hazard of death from any cause was 29% higher among former smokers (hazard ratio, 1.29; 95% confidence interval, 1.08-1.55), and 39% higher among current/recent smokers (hazard ratio, 1.39; 95% confidence interval, 1.16-1.67). Factors predicting worse overall survival among never-smokers included Hispanic ethnicity, severe comorbidity, undifferentiated histology, and regional or distant stage. Never-smoking Hispanics appeared more likely to have regional or advanced disease at diagnosis and less likely to undergo surgical resection, although these differences were not statistically significant.

CONCLUSIONS

Never-smokers with lung cancer are more likely than ever-smokers to be female, Asian or Hispanic, and more advantaged socioeconomically, suggesting possible etiologic differences in lung cancer by smoking status. Among never-smokers, Hispanics with lung cancer had worse survival than non-Hispanic whites.