Interstitial lung disease associated with gefitinib

Although pulmonary toxicity associated with gefitinib, an epidermal growth factor receptor inhibitor, has been reported recently, the accumulation of clinical information and the underlying mechanisms of gefitinib-induced interstitial lung disease (ILD) remain insufficient and unclear. After retrospectively reviewing the clinical records and chest X-rays of 489 lung cancer patients who were treated with gefitinib, we diagnosed four cases of gefitinib-induced ILD who underwent fiberoptic bronchoscopy and bronchoalveolar lavage (BAL). We found that the period of time from starting gefitinib to the onset of ILD was short, and concluded that a careful and close observation of a chest imaging study and a collection of respiratory symptoms was recommended. All four patients were treated with a high dose of corticosteroids, and ILD was resolved. We detected high levels of interferon-inducible protein-10 in BAL fluid, although we could not demonstrate the characteristic features of laboratory findings or BAL fluid cell analysis. We speculated that a Th1 type of lung tissue inflammation or lung injury might be involved as a part of mechanisms underlying gefitinib-induced ILD.