Study to Determine if Contacting Patients With MTC More Frequently Results in Earlier Detection and Treatment of Signs and Symptoms of AEs and Thus a Decrease in the Percentage of Time Patients Experience AEs During First 12 Months on Vandetanib Treatment

Inclusion Criteria: * Provision of informed consent prior to any study specific procedures * Female or male aged 18 years and over * Previously confirmed histological diagnosis of unresectable, locally advanced or metastatic hereditary or sporadic MTC. Documentation must be provided in patient's medical chart * WHO or ECOG Performance status 0-2 * Negative pregnancy test (urine or serum) for female patients of childbearing potential Exclusion Criteria: * Unstable brain metastases or spinal cord compression that require treatment, unless treated at least 4 weeks before first dose and stable without steroid treatment for 10 days * Major surgery within 4 weeks before randomization * The last dose of prior chemotherapy received less than 3 weeks prior to randomization * Radiation therapy not completed prior to the first dose of vandetanib * Significant cardiac event, superior vena cava syndrome, NYHA classification of heart disease ≥2, within 12 weeks before randomization, or presence of cardiac disease that in the opinion of the Investigator increases risk of ventricular arrhythmia * Creatinine clearance \<30 ml/min (calculated by Cockcroft-Gault formula),Patients with moderate renal impairment, defined as creatinine clearance ≥30 to \<50 ml/min, must start vandetanib at a reduced dose of 200 mg