Pathologic complete response in metastatic right-sided colon cancer treated with panitumumab and FOLFOX4 chemotherapy regimen

Abstract

Introduction. Recommended biological agents for the first-line treatment of left-sided metastatic colorectal cancer (mCRC) without mutations in RAS/BRAF genes are cetuximab or panitumumab, while for rightsided mCRC bevacizumab is advised instead. For transversal colon mCRC the data about biological treatment efficacy is lacking. We present a patient with right-sided mCRC originated from transversal colon where panitumumab and chemotherapy treatment resulted in an excellent outcome. Case outline. A 56-year-old woman was diagnosed with transversal colon adenocarcinoma, without RAS genes mutations, with multiple liver metastases disseminated in both lobes. After the operation of the primary tumor, the patient was treated with panitumumab and FOLFOX4 chemotherapy regimen. After two months of treatment, the dramatic response was evident ? The diameter sum of the target lesions decreased by 70.5%. After two more months of therapy, further decrease by 22.5% was evident. Liver metastases were operated on. Histopathology revealed fibrotic and necrotic tissue in all suspicious lesions, except in one focus, where adenocarcinoma was found, but with 90% of surrounding necrosis. Twelve months after liver surgery the patient is without signs of the progressive disease. Conclusion. Detailed comprehensive studies of genetic features of mCRC hold a key to personalized treatment options and better outcomes for patients with mCRC.