Idiopathic pulmonary fibrosis and lung cancer: future directions and challenges

Abstract

Idiopathic pulmonary fibrosis (IPF) is a progressive disease of pulmonary scarring. New treatments slow disease progression and allow pulmonary fibrosis patients to live longer. Persistent pulmonary fibrosis increases a patient's risk of developing lung cancer. Lung cancer in patients with IPF differs from cancers that develop in the non-fibrotic lung. Peripherally located adenocarcinoma is the most frequent cell type in smokers who develop lung cancer, while squamous cell carcinoma is the most frequent in pulmonary fibrosis. Increased fibroblast foci in IPF are associated with more aggressive cancer behaviour and shorter doubling times. Treatment of lung cancer in fibrosis is challenging because of the risk of inducing an exacerbation of fibrosis. In order to improve patient outcomes, modifications of current lung cancer screening guidelines in patients with pulmonary fibrosis will be necessary to avoid delays in treatment. 2-fluoro-2-deoxy-d-glucose (FDG) positron emission tomography (PET) computed tomography (CT) imaging can help identify cancer earlier and more reliably than CT alone. Increased use of wedge resections, proton therapy and immunotherapy may increase survival by decreasing the risk of exacerbation, but further research will be necessary.

FIGURE 1

Evolution over 6 months of mucinous adenocarcinoma in a background of usual interstitial pneumonia on chest computed tomography. The cancer looks like consolidation, making early diagnosis challenging.

FIGURE 2

a) An axial chest computed tomography (CT) image and b) a fused axial 2-fluoro-2-deoxy-d-glucose (FDG) positron emission tomography (PET)-CT image demonstrate peripheral squamous cell cancer occurring in a patient with a “probable usual interstitial pneumonia” pattern. There is low maximum standardised uptake value (SUV_max) in fibrotic lung parenchyma compared to tumour SUV_max of 12.5.