A case of drug-induced interstitial pneumonia caused by S-1 and CPT-11 combination therapy for advanced colon cancer

The patient was a 77-year-old woman admitted for nausea and abdominal pain. Computed tomography (CT) revealed advanced ascending colon cancer with liver metastasis. After operation, we started combination chemotherapy of S-1 and irinotecan (CPT-11); S-1(80 mg/m2) administered orally for consecutive days followed by 14 days rest.CPT -11 (100 mg/m2) was given as a 2-hour infusion on day 1 and 15. The patient complained of high fever and subsequent dyspnea with severe hypoxemia after the first course of combination chemotherapy of S-1 and CPT-11.CT scan showed diffuse interstitial lesions with ground glass opacity on both lungs. Steroid pulse therapy with oxygen therapy remarkably improved her symptoms, and abnormal findings on CT scan also resolved. Drug lymphocyte stimulation test was positive against S-1 and negative against CPT-11. These findings were consistent with S-1-induced lung injury. Drug -induced pneumonia needs to be considered in the differential diagnosis when patients treated with S-1 and CPT-11 combination therapy present high fever and dyspnea.