Efficacy and safety of first-line cetuximab therapy for older patients (aged ≥ 70 years) with RAS wild-type metastatic colorectal cancer: a nationwide real-world study

This study investigated the efficacy and safety of first-line cetuximab-based chemotherapy for patients aged 70 years and older with <i>RAS</i> wild-type metastatic colorectal cancer (mCRC) from nationwide registry data in Taiwan. The study included 756 patients with <i>RAS</i> wild-type mCRC who received cetuximab and chemotherapy as first-line therapy at multiple institutions in Taiwan from November 2016 to January 2021. After the prognoses of two age groups (≥ 70 and < 70 years) were determined, progression-free survival (PFS) and cancer-specific survival (CSS) were regarded as the primary endpoints and severe adverse events (SAEs) were also compared. The median PFS and CSS were similar in the two age groups (14.0 vs. 14.0 months, <i>P</i> = 0.098; 32.0 vs. 35.0 months, <i>P</i> = 0.226, respectively). Subgroup analysis revealed similar PFS and CSS in the two age groups for patients with synchronous versus metachronous mCRC and left-sided versus right-sided tumors (all <i>P</i> > 0.05). In terms of hematologic SAEs, the incidence of grade 3 or more severe anemia was significantly higher in the older group (13.3% vs. 5.0%, <i>P</i> = 0.003). No significant between-group difference was found in the incidence of nonhematologic SAEs (all <i>P</i> > 0.05). According to our nationwide real-world registry data, older patients with <i>RAS</i> wild-type mCRC who are treated with first-line cetuximab-based chemotherapy may experience similar benefits to those experienced by younger patients. Significant differences between patients aged ≥ 70 and < 70 years were found for no hematologic and nonhematologic SAEs except grade 3 or more severe anemia. In summary, cetuximab is an effective therapeutic agent as first-line therapy for older patients with <i>RAS</i> wild-type mCRC.