It is assumed, that the patients of the standard arm show a median progression-free survival time of 4.4 months those of the experimental arm of at least 6.9 months. Assuming a recruitment period of 18 months and follow-up for at least 12 months a total sample size of 174 patients is required (two-sided, α=0.05, 80% power). To account for 5% drop-outs 184 patients will be randomized.