Readministration of Cancer Drugs in a Patient withChemorefractory Metastatic Colorectal Cancer

A 63-year-old woman was admitted to our institution for severe pain in her right lower abdomen caused by the perforation of cecalcancer. She underwent emergency surgery, from which she was diagnosed with cecal carcinoma with liver, lung, and lymph nodemetastases. As she was taking aspirin to prevent cerebral infarction, anti-vascular endothelial growth factor (receptor) antibody andregorafenib therapy were not used. Thus, we started a modified FOLFOX 6+cetuximab regimen. Thisfirst-line treatment initiallyachieved a partial response (PR), but she then developed progressive disease (PD) after 14 months. We changed the regimen toFOLFIRI, followed by trifluridine/tipiracil, but her progression-free survival periods were 2.7 months and 1 month, respectively.Although we cycled through the available array of standard cancer drugs, the patient showed a good performance status, andsome benefit from treatment still seemed plausible. We readministered the 5-fluorouracil oral preparation S-1, whichmaintained stable disease (SD) for 7 months. After PD emerged, we readministered the anti-epidermal growth factor receptor(EGFR) antibody panitumumab for 7.5 months of SD. Finally, 39 months after her diagnosis, she died from rapidly progressingdisease. However, her relatively long survival implies that readministering drugs similar to those used in previous regimensmight benefit patients with metastatic colorectal cancer