Clinical Characteristics and Coexistence of Malignancy in Patients with Respiratory Bronchiolitis-Associated Interstitial Lung Disease

INTRODUCTION: Respiratory bronchiolitis-associated interstitial lung disease (RB-ILD) is an extremely rare condition classified as smoking-related interstitial pneumonia. The purpose of this study was to investigate the demographic, radiological, and pulmonary function characteristics of patients diagnosed with RB-ILD based on radiological findings. In this study, we aimed to investigate the co-occurrence of lung cancer and non-lung cancers in patients with RB-ILD.
METHODS: Radiological images consistent with RB-ILD presentation (centrilobular opacity, ground glass areas, and air trapping) who attended the our center, were included in the study. Included patients were age 18 years and older, had a history of smoking (active or ex-smoker), and presented radiological evidence of RB-ILD. Demographic data, such as age, sex, cigarette packs smoked and history (pack-years), occupation, comorbidities, cancer frequency, and pulmonary function parameters were assessed.
RESULTS: The study included 60 patients of which 91.7% were male. The mean age was 60.9±12.5 years, and the mean cigarette pack-year history was 33.7±12.0. Pulmonary function tests indicated small airway obstruction. Malignancy was present in 51.7% of patients with RB-ILD, with the most common types being small-cell lung cancer, colon cancer, gastric cancer, and prostate cancer. Patients were assigned into groups based on the presence of malignancy, with no significant differences found in gender, age, cigarette pack-years, and pulmonary function test values.
DISCUSSION AND CONCLUSION: This study is the first nationwide investigation reporting the coexistence of RB-ILD and malignancy in a selected population of smokers. Besides smoking cessation, close monitoring for lung and extrapulmonary cancer development is advised for patients with RB-ILD.

Keywords: Respiratory bronchiolitis, interstitial lung disease, respiratory function test, cancer frequency, lung cancer