Cetuximab plus irinotecan after irinotecan failure in elderly metastatic colorectal cancer patients: clinical outcome according to KRAS and BRAF mutational status

Abstract Background Scarce data are available about safety and efficacy of cetuximab in elderly metastatic colorectal cancer (mCRC) patients. Patients and methods We retrospectively analysed 54 irinotecan-refractory mCRC patients aged ≥ 70 years treated with cetuximab plus irinotecan and evaluated clinical outcome according to KRAS and BRAF mutational status. Results Median age was 73 years (70–82). Main grade 3–4 toxicities were skin rash (15%), diarrhea (19%) and neutropenia (13%). Irinotecan dose reduction was necessary in 39% of patients. Fifty-two (96%) patients were analysed for KRAS and BRAF status. The 29 KRAS wild-type patients achieved better RR (31% vs 4%; p  = 0.030) and median PFS (4.21 months vs 3.95 months; p  = 0.034; HR: 0.50, 95% CI: 0.27–0.95) when compared with KRAS mutated ones. RR (41% vs 3%; p  = 0.001) and mPFS (4.57 months vs 3.78 months, p  = 0.001; HR: 0.35, 95% CI: 0.19–0.66) were significantly higher among the 22 KRAS and BRAF wild-type patients compared to the 30 KRAS or BRAF mutated ones. Conclusion Cetuximab plus irinotecan has a favourable safety profile in elderly mCRC patients, but a reduced dose of irinotecan should be considered. Such a combination can be a useful option for elderly KRAS and BRAF wild-type patients.