Cetuximab for Elderly Patients With mCRC

Primary endpoint: If in a treatment arm the number of patients alive and without progression at 12 weeks is 17 or more, this arm will be considered promising, otherwise not promising. Additionally, a two-sided 95% confidence interval for the difference in Progression free survival (PFS) rates between the two arms will be calculated. Secondary endpoints and patient characteristics: * Laboratory values may be expressed as the absolute values (continuous variables) or/and as grading (ordinal categorical variables). * Generally for each categorical variable the results will be summarized by frequencies and percentages. For response rates 95% Clopper-Pearson confidence intervals will be calculated. * For each adverse event, the results will be summarized by frequencies and percentages of different grades among all cycles as well as by frequencies and percentages of the within-patient worst grades * For each continuous variable the results will be summarized by descriptive statistics. * Time-to-event variables will be presented by Kaplan-Meier curves and summarized by medians and 95% confidence intervals. * All analysis will be done by treatment arm.