Lung cancer in nonsmokers- A risk factor analysis

Abstract

Institutions:stony brook medical centerrationaleLung Cancer screening for the high-risk smoking population has been proven to save lives. However, in 2022, 20% of newly diagnosed lung cancers (47,300) were in nonsmokers. These patients were found to be diagnosed at later stages. This may be at least partly due to not meeting criteria for and participating in current lung cancer screening. This study aims to describe characteristics of a never smoker patient population to help identify common risk factors which might merit inclusion in lung cancer screening and thus improve patient outcomes. MethodsThis retrospective single center study included never-smoker patients diagnosed with lung nodules and never-smoker patients diagnosed with lung cancer from 2016 to 2022. Data was obtained from the Stony Brook Medical Center electronic medical record. 16,056 patients were identified as never-smokers who were asked by the medical assistant if they ever smoked in their lifetime. Patients were eliminated if they had any smoking history up to first diagnosis date. Demographics, radiology, histology, diagnosis dates, comorbidities, smoking status, and exposures collected through ICD10 codes and not self-reported, were investigated. ResultsOf 16,056 never-smoking patients, 9315 (58.02%) were females diagnosed with lung nodules and 6741 (41.98%) were males diagnosed with lung nodules.The univariate analysis showed significant differences between gender, age at nodule diagnosis, and patients with and without comorbidities including chronic obstructive pulmonary disease (COPD), hypertension (HTN), and family history (FHX) of lung cancer. The percentage of lung cancer patients among females was significantly higher than among males. Patients having lung cancer were older. The percentages of lung cancer patients with these comorbidities were significantly higher than those without. However, there was no significant difference found between patients with and without diabetes mellitus (DM).The multivariable logistic regression suggested that age at nodule diagnosis and comorbidities including COPD (which included asthma, emphysema and chronic bronchitis) and family history of lung cancer were significantly associated with lung cancer. Older patients and patients with those comorbidities had a higher risk of developing cancer than those who were younger or without those comorbidities. The study excluded HTN and included age at nodule diagnosis in the logistic regression model as HTN was found to be protective against lung cancer due to age at lung nodule diagnosis. Please refer to the appendix for further details. ConclusionNever-smoker patients who were older and with COPD and Family History of lung cancer had higher risk of developing lung cancer than younger patients without these comorbidities. In this study, gender had no impact on outcome.