A Real-World Retrospective Study to Evaluate the Reliability of Cetuximab plus Capecitabine versus Capecitabine as Maintenance Therapy in Patients with RAS and BRAF Wild-Type Metastatic Colorectal Cancer.

Background: The optimal maintenance therapy for rat sarcoma (RAS) and v-raf murine sarcoma viral oncogene homolog B (BRAF) metastatic colorectal cancers (mCRCs) remains unclear. It is critical to evaluate the reliability of cetuximab-capecitabine (the observation group) relative to capecitabine alone (control group).

Patients And Methods: In this retrospective analysis, patients with RAS and BRAF mCRC admitted to Huizhou Municipal Central Hospital, between January 2016 and October 2020 were enrolled and treated with cetuximab plus 5-fluorouracil, leucovorin, and irinotecan (FOLFIRI) as an initial therapy. Patients whose disease was controlled after at least six cycles of treatment were administered a maintenance therapy until disease progression. We also analyzed the prognosis of patients according to clinicopathological features. Altogether, 39 RAS and BRAF mCRC patients were recruited from January 2016 to October 2020, with 18 cases in the treatment group and 21 cases in the control group. The difference in baseline clinicopathological features between the two treatments is not obvious.

Results: The median progression-free survival after maintenance treatment in observation group (9.5 months [95% confidence interval (CI) = 6.4-12.6]), was significantly better than the control group (7.3 months [95% CI = 5.8-8.8]). During maintenance treatment, there were no deaths caused by treatment-related adverse events, and the overall incidence of rash acne was different between the observation and control groups (p < 0.05). Most adverse events were mild and easily controlled. Primary tumor site, baseline carcinoembryonic antigen levels, and microsatellite instability status were independent prognostic factors.

Conclusion: Maintenance therapy using cetuximab plus capecitabine improved survival in patients with mCRC and was well tolerated by patients.