Refractory Irinotecan-Induced Interstitial Pneumonitis after Treatment of Metastatic Lung Cancer from the Rectum: A Case Report

A 64-year-old man underwent low anterior resection for rectal cancer at a local hospital in 1999. In February 2005metastases to the brain and left lung were detected. The brain metastasis was treated with focal radiation therapy(gamma knifeand lung metastasis was treated with radio frequency ablation. The patient was referred to our department for systemic chemotherapy with irinotecan. Seventeen days after the first dose of irinotecanhe came to our emergency room with acute respiratory failure due to interstitial pneumonitis. Steroid pulse therapy was unsuccessful and the patients physical condition gradually worsened until his death in November 2005. Autopsy revealed no evidence of malignant cells in the left lung. Howeverinterstitial pneumonitis with extensive fibrosis was confirmed. Myelosuppression and diarrhea are well-known adverse effects of irinotecan. Interstitial pneumonitis in cases of metastatic lung cancer from colorectal cancer accounted for only 0.05% (8 of 15385of all cases of irinotecan-induced side effects in one previous study. Howeverclinicians should be aware of the possibility of interstitial pneumonitis after the administration of irinotecan for metastatic lung cancer following colorectal cancer. (Jikeikai Med J 2006;53:159-62