• Division of Cancer Prevention, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA. pp4f@nih.gov

BACKGROUND: Chest radiographs (CXRs) are commonly performed for diagnostic and other purposes. There is little literature either on the prevalence in the general population of various abnormalities seen on CXRs or on the risks associated with these abnormalities.

METHODS: We followed up > 70,000 men and women who were enrolled in the Prostate, Lung, Colorectal and Ovarian Cancer Screening Trial. Subjects received four annual posteroanterior CXRs for the early detection of lung cancer. Radiologists noted the presence of non-cancer-related abnormalities as well as nodules/masses that were suspicious for lung cancer. Subjects were followed up for mortality and cancer incidence.

RESULTS: Abnormalities that were not suspicious for lung cancer were observed on 35% of examinations, compared to 8% of examinations with findings that were suspicious for cancer. The most commonly reported noncancer abnormalities were granuloma (10.7% of examinations), scarring/pulmonary fibrosis (8.2% of examinations), bone/soft tissue lesions (5.5% of examinations), cardiac abnormalities (4.4% of examinations), pleural fibrosis (3.6% of examinations), and COPD/emphysema (2.5% of examinations). Most noncancer abnormalities were more prevalent in men, older subjects, and smokers. Controlling for age, smoking, and other factors, scarring/pulmonary fibrosis was significantly associated with an increased risk of lung cancer with a hazard ratio (HR) of 2.0, while cardiac abnormalities (HR, 2.1), scarring/pulmonary fibrosis (HR, 1.4), COPD (HR, 1.7), and pleural fluid (HR, 2.3) were significantly associated with increased overall (ie, non-lung cancer) mortality.

CONCLUSION: Abnormalities that are not suspicious for lung cancer are common in a population undergoing screening. Some of these abnormalities are associated with an increased risk for lung cancer incidence and/or overall mortality.