[A Case of Rectal Cancer Completely Resected after Successful Treatment with Irinotecan plus Cetuximab-Induced Interstitial Pneumonia with Steroid Pulse Therapy].

We report of a 74-year-old man with advanced rectal cancer invading the small intestine and bladder. Initially, 3 courses of neoadjuvant chemotherapy with FOLFIRI and cetuximab were administered. At the beginning of the 4 course, the patient experienced fever and dyspnea. Chest radiography and computed tomography showed ground-grass opacities in both lungs. He was diagnosed with interstitial pneumonia induced by irinotecan or cetuximab. Steroid pulse therapy consisting of methyl-prednisolone (1,000 mg/day; 3 days) with respiratory assist resulted in significant improvement, and prednisolone was continued while reducing the dose gradually. He stopped the medicine on the 106th day from the first treatment, and underwent the R0 operation on the 113th day. We report for the first time a case of interstitial pneumonia occurring after neoadjuvant chemotherapy for advanced rectal cancer that was successfully resected after treatment.