A method for screening a patient for angioinhibition resistance and treating said patient having a disease susceptible to treatment via an anti-angiogenic agent. The screening method includes an assay for identifying the presence of angioinhibition resistance in patients by collecting patient blood or serum and subjecting it to a Chick Chorioallantoic Membrane (CAM) angiogenesis assay configured for accepting a human tumor wherein the human tumor xenograft includes a vasculature system. The screening method and assay further includes steps that include using the CAM results for identifying the endogenous pro-angiogenic non-peptide hormone concentrations of the blood sample by calculating the vascular activity of the vasculature system of the human tumor xenograft in the presence of anti-angiogenic drugs and inducing in the patient, a state of subclinical hypothyroidism prior to commencing anti-angiogenic treatment.
