[Two cases of interstitial pneumonia caused by cetuximab plus mFOLFOX6 therapy in metastatic colorectal cancer patients].

Case 1: A 69-year-old man was diagnosed with rectal cancer and liver metastasis. After low anterior resection, mFOLFOX6 plus cetuximab therapy was started for resection of the liver metastasis. However, he had to forgo liver resection because he developed acute exacerbation of interstitial pneumonitis (IP) after 6 courses of chemotherapy. Despite beginning the second-line treatment with mFOLFOX6 plus bevacizumab, he died in June 2012. Case 2: A 71-year-old man had undergone sigmoidectomy for sigmoid colon cancer in 2005, and right lower lobe partial resection for metastatic lung cancer in 2006. Although radiofrequency ablation or transcatheter arterial chemoembolization had been performed for multiple liver metastases several times since 2007, his multiple liver metastases were uncontrollable. Therefore, FOLFOX4 therapy was started in 2010, and mFOLFOX6 plus cetuximab therapy was substituted for FOLFOX4 therapy in 2011. The patient died in March 2012 due to the rapid development of IP, and thus, it appears that IP was the cause of death in both patients. The general condition, including pulmonary function, of patients at risk of IP must be checked before starting cetuximab therapy for metastatic colorectal cancer.