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

Scarce data are available about safety and efficacy of cetuximab in elderly metastatic colorectal cancer (mCRC) patients.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.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.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.