Idiopathic pulmonary fibrosis (IPF) is reportedly associated with an increased risk of lung cancer. However, few studies have explored whether IPF affects the long-term survival of lung cancer patients. The primary goal of this study was to evaluate the characteristics of lung cancer in IPF patients and impact of IPF on lung cancer survival.

Seventy IPF patients with histologically proven lung cancer were identified through a search of the Seoul National University Bundang Hospital database between 2003 and 2012. Of these, 33 patients who had undergone surgery were matched with 66 patients who had lung cancer without IPF. Matched variables included age, sex, histologic type, and lung cancer stage.

Of the 70 subjects, 94% were male, and the mean age was 70 years (range, 46–90). In total, 81% of the tumors were located in the lung periphery, and 56% were in the lower lobe. The majority of cancers (70%) were observed in the fibrotic area on chest computed tomography scans. The most frequent histologic type was squamous cell carcinoma (40%). Among surgically treated patients (33 cases and 66 controls), the 5-year survival rates were 38% for lung cancer patients with IPF and 73% for those without IPF (p = 0.001).

Squamous cell carcinoma was the most common type of lung cancer in IPF patients. IPF reduced the survival of surgically treated lung cancer patients regardless of age, sex, histologic type, and/or lung cancer stage.