Bronchoscopy is useful to evaluate some NSCLC patients with dyspnoea to assess extension of the cancer and to exclude an opportunistic infection using bronchioalveolar lavage. However, the value of a bronchoscopy in establishing the diagnosis of drugassociated ILD is less clear, since bronchioalveolar lavage is not specific for drug-associated disease, and biopsies obtained by transbronchial biopsy are small and often do not yield enough tissue to make this distinction. Open lung biopsy is rarely performed in NSCLC patients with respiratory distress since most patients have advanced disease with a limited prognosis. Furthermore, procedures requiring surgery are not usually believed to arrive at a definitive diagnosis of drug-associated ILD.