Risk factors, clinical features, and impact on survival of lung cancer in patients with idiopathic pulmonary fibrosis: A retrospective study.

Idiopathic pulmonary fibrosis (IPF) is a chronic progressive lung disease, and lung cancer is a significant comorbidity with high prevalence and adverse impact on survival. Early detection of IPF and targeted interventions require understanding the associated risk factors and clinical presentation of lung cancer in IPF. This single-center, retrospective cohort study aimed to identify risk factors for lung cancer in IPF patients, investigate its clinical features, and determine its impact on survival. Of the 1481 patients with interstitial lung disease, 436 met the criteria for IPF per American Thoracic Society/European Respiratory Society guidelines. Patients followed up for <6 months (n = 31), patients with both IPF and lung cancer (n = 19), and patients whose data were incomplete (n = 18) were excluded from the study. In the end, the study group consisted of 59 patients who developed lung cancer during follow-up, and the control group consisted of 59 randomly selected IPF patients without cancer. Patients' clinical, radiological, and laboratory data were collected from their medical records. The mean age of the sample, 83.9% of which was male, was 66.9 ± 8.3 years. Emphysema, low body mass index, absence of antifibrotic therapy, presence of weight loss symptoms, and ≥36 pack-years of smoking were significant risk factors for lung cancer (P <.05), as also confirmed by multivariate analysis. Squamous cell carcinoma was the most common histological type (45.8%), with lower lobe predominance (59.3%) and peripheral location (78.0%). Most tumors (78.0%) were within or adjacent to fibrotic tissue. The median time from IPF diagnosis to lung cancer development was 2.80 years. The 0 to 3, 3 to 5, and >5-year mortality rates for patients with and without lung cancer were 15.2% to 3.3%, 35.5%- 8.4%, and 42.3% to 15.2%, respectively (P = .026). Our study identified significant risk factors for lung cancer in IPF patients and demonstrated its negative impact on survival. The presence of emphysema, low body mass index, absence of antifibrotic therapy, and ≥36 pack-years of smoking were significantly associated with lung cancer development. Awareness of these factors is crucial for early diagnosis and appropriate treatment strategy determination, potentially improving outcomes in this high-risk population.