A method of using an electrode array to deliver tumor treating electric fields to a patient including the steps of: placing a plurality of electrode elements in optimized locations on the patient, each of the electrode elements being independently programmable, the optimized locations are optimized relative to a target area wherein at least one tumor is located; programming a control device with a frequency range, a firing configuration and a firing sequence for the plurality of electrode elements; and generating electrical signals in the frequency range, the electrical signals being directed to at least two of the plurality of electrode elements in a sequence determined by the firing sequence.