Rechallenge and maintenance therapy using cetuximab and chemotherapy administered to a patient with metastatic colorectal cancer.

BACKGROUND: Cetuximab combined with chemotherapy is one of the first-line treatments of metastatic colorectal cancer. Although disease progression inevitably occurs, rechallenge and maintenance therapies using cetuximab-based regimens may be beneficial, particularly for patients with wild-type (WT) KRAS.

CASE PRESENTATION: A 47-year-old female patient who underwent right hemicolectomy presented with an ulcerative adenocarcinoma (grade 2) revealed by histopathological analysis. The patient received three cycles of adjuvant chemotherapy, but disease recurred 15 months later. Cetuximab and a FOLFOX-4 regimen were administered, followed by surgery and adjuvant chemotherapy that was administered for approximately one year. Three years after completing adjuvant therapy, her serum carcinoembryonic antigen levels rapidly increased, and enhanced computed tomography showed widespread metastases. Rechallenge with cetuximab and the FOLFIRI regimen was then initiated, and after 12 cycles, lesions in the lung and liver shrank significantly, and serum CEA levels dramatically declined. Maintenance therapy with cetuximab and capecitabine was then administered for 10 months until the metastatic lesions in the lung and liver enlarged.

CONCLUSION: Rechallenge and maintenance therapy with cetuximab-based chemotherapy were relatively effective for managing a female patient with WT KRAS. Optimization of this strategy requires further in-depth investigations of more patients.