KRAS mutations as an independent prognostic factor in patients with advanced colorectal cancer treated with cetuximab

Astrid Lièvre, Jean Baptiste Bachet, Valérie Boige, Anne Cayre, Delphine Le Corre, Emmanuel Buc, Marc Ychou, Olivier Bouché, Bruno Landi, Christophe Louvet, Thierry André, Fréderic Bibeau, Marie Danièle Diebold, Philippe Rougier, Michel Ducreux, Gorana Tomasic, Jean François Emile, Frédérique Penault-Llorca, Pierre Laurent-Puig

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    Abstract

    Purpose: Cetuximab is efficient in advanced colorectal cancer (CRC). We previously showed that KRAS mutations were associated with resistance to cetuximab in 30 CRC patients. The aim of this study was to validate, in an independent larger series of 89 patients, the prognostic value of KRAS mutations on response to cetuximab and survival. Patients and Methods: Eighty-nine metastatic CRC patients treated with cetuximab after treatment failure with irinotecan-based chemotherapy were analyzed for KRAS mutation by allelic discrimination on tumor DNA. The association between KRAS mutations and tumor response, skin toxicity, progression-free survival (PFS) and overall survival (OS) was analyzed. Results: A KRAS mutation was present in 27% of the patients and was associated with resistance to cetuximab (0% v 40% of responders among the 24 mutated and 65 nonmutated patients, respectively; P < .001) and a poorer survival (median PFS: 10.1 v 31.4 weeks in patients without mutation; P = .0001; median OS: 10.1 v 14.3 months in patients without mutation; P = .026). When we pooled these 89 patients with patients from our previous study, the multivariate analysis showed that KRAS status was an independent prognostic factor associated with OS and PFS, whereas skin toxicity was only associated with OS. In a combined analysis, median OS times of patients with two, one, or no favorable prognostic factors (severe skin toxicity and no KRAS mutation) was of 15.6, 10.7, and 5.6 months, respectively. Conclusion: These results confirm the high prognostic value of KRAS mutations on response to cetuximab and survival in metastatic CRC patients treated with cetuximab.

    Original languageEnglish
    Pages (from-to)374-379
    Number of pages6
    JournalJournal of Clinical Oncology
    Volume26
    Issue number3
    DOIs
    Publication statusPublished - 20 Jan 2008

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