Efficacy and Safety of Oxaliplatin-based Regimens as First-line Chemotherapy in Elderly Patients With Metastatic Colorectal Cancer

Background/Aim: Metastatic colorectal cancer (mCRC) is mainly a disease of the elderly. The aim of this retrospective study was to investigate the efficacy and safety of oxaliplatin-based regimens as first-line chemotherapy in elderly patients with mCRC. Patients and Methods: We recruited mCRC patients aged >= 75 years who were treated with oxaliplatin-based chemotherapy as first-line therapy from October 2011 to November 2020. Primary outcome was median progression-free survival (PFS) and incidence of adverse events, while secondary outcomes included overall survival (OS), relative dose intensity (RDI) and tumor response rate. Results: The study enrolled 41 patients with mCRC aged >= 75 years. Median PFS and OS were 9.3 months and 38.9 months, respectively. Median rate of starting dose per standard dose and median RDI of L-OHP were 94.6% [interquartile range (IQR)=80.0-100] and 52.4% (IQR=30.2-71.1), respectively. The most common adverse events of grade >= 3 were neutropenia (21.4%), high blood pressure (16.7%), and anorexia (14.3%). Conclusion: Although the RDI of L - OHP drug was low, the PFS, OS, and incidence of adverse events were similar to previous reports of oxaliplatin-based regimens not limited to the elderly. Oxaliplatin-based regimens as first-line chemotherapy may be safely and effectively adapted to patients aged >= 75 years with mCRC by continuing chemotherapy with implementation of a reduction and discontinuation of anticancer drugs depending on adverse events.