A method for determining whether a patient in need thereof will respond to anti-VEGF antibody based chemotherapy by screening a suitable cell or tissue sample isolated from the patient for at least one genomic polymorphism or genotype selected from (i) IL-8(-251); (ii) VEGF(936); or (iii) AM (3' CA repeats), wherein the patient is suitably treated if the corresponding genotype is (i) (T/T) for IL-8(-251); (ii) (T/T or C/T) for VEGF(936); or (iii) at least one AM allele having 14 or more 3' CA repeats.