Reduced forced expiratory volume in one second (FEV1) has been linked to non small cell lung cancer (NSCLC). However, it is unclear what NSCLC histologic subtypes are associated with FEV1. Moreover, there is little information on whether sex modifies this relationship. We investigated the relationship between FEV1 and subtypes of NSCLC, and if it is modified by sex.
We used data, including FEV1, from patients who underwent tumor resection for NSCLC at a teaching hospital in Vancouver. We divided the cohort into quartiles of predicted FEV1. Using logistic and linear regression we determined whether FEV1 was related to the occurrence of adeno or squamous cell carcinoma in men and women.
There were 610 patients in the study (36% females). Women were more likely to have adenocarcinoma than men (72% vs. 40% respectively; p<0.001). In women, there was no significant relationship between FEV1 and risk of any histological subtypes of NSCLC. At all FEV1 values, 70% of all NSCLC were adenocarcinoma in women. However, in men there was an inverse relationship between the risk of adenocarcinoma and FEV1. The lowest quartile of FEV1 was 47% less likely to have adenocarcinoma compared with the highest FEV1 quartile (adjusted odds ratio, 0.52; 0.28 to 0.98; p for trend 0.028). The reverse was observed for squamous cell carcinoma.
In individuals undergoing resection for NSCLC, the risk of adenocarcinoma and squamous cell carcinoma of the lung varies as a function of FEV1, independent of smoking intensity in men but not in women. In women, adenocarcinoma predominates across all levels of FEV1.
Women and men may differ in their airway biology, which may be responsible for the differential susceptibility to histologic subtypes of NSCLC. Animal models suggest that the females airway inflammatory response to cigarette smoke is increased. Further research into the role of inflammation in adenocarcinoma as well as hormonal, molecular and genetic differences will aid in the understanding of disease modifying effects of gender in individuals with NSCLC.
Samir Malhotra, Grant monies (from sources other than industry) Dr. Don Sin: Canada Research Chair (Respiration) and a Michael Smith/St. Paul’s Hospital Foundation Professorship in COPD.