Lung cancer is the leading cause of cancer mortality in the developed world. Diffuse fibrosing interstitial lung disease (ILD) consist of a heterogeneous group that includes idiopathic pulmonary fibrosis (IPF). Diffuse ILD is a risk factor for the development of lung cancer which on its own is associated with an increased risk of morbidity and mortality. Despite common mechanisms between fibrogenesis and carcinogenesis, the underlying pathogenesis of lung cancer and fibrosis overlap is poorly understood. The clinical management of these patients remains a medical challenge requiring a multidisciplinary approach, particularly in view of the risk of acute exacerbation of fibrosing ILD following most lung cancer treatments, leading to a considerable negative outcome on overall prognosis.