Lung cancer (LC) is frequently associated with idiopathic pulmonary fibrosis (IPF). Despite this well-known association, the outcome of LC in patients with IPF is unclear. The objective of this study was to evaluate the impact of LC on survival of patients with associated IPF.
A total of 260 patients with IPF were reviewed, and 186 IPF cases had complete clinical and follow-up data. Among these, five cases were excluded because LC was radiologically suspected but not histologically proven. The remaining 181 cases were categorized in two groups: 23 patients with biopsy-proven LC and IPF (LC-IPF) and 158 patients with IPF only (IPF). Survival and clinical characteristics of the two groups were compared.
Prevalence of histologically proven LC was 13%, and among those with LC-IPF cumulative incidence at 1 and 3 years was 41% and 82%. Patients with LC were more frequently smokers (91.3% vs 71.6%, P = .001), with combined pulmonary fibrosis and emphysema (52% vs 32%, P = .052). Survival in patients with LC-IPF was significantly worse than in patients with IPF without LC (median survival, 38.7 months vs 63.9 months; hazard ratio = 5.0; 95% CI, 2.91-8.57; P < .001). Causes of death in the study group were respiratory failure in 43% of patients, LC progression in 13%, and LC treatment-related complications in 17%.
In patients with IPF, LC has a significant adverse impact on survival. Diagnosis and treatment of LC in IPF are burdened by an increased incidence of severe complicating events, apparently as lethal as the cancer itself.