Tumor Treating Fields (TTFields) can be used to treat tumors (and/or prevent metastases) in or near a person's neck by affixing a first transducer array (i.e., a set of electrode elements) to the person's head and affixing a second transducer array to the person's chest. Subsequently, an AC voltage at a desired frequency (e.g., 100-300 kHz) is applied between the first transducer array and the second transducer array. This induces an electric field that is strong enough to be effective (e.g., greater than 1 V/cm) in most of the person's neck. In some embodiments, the center of the first transducer array is positioned on the vertex of the head or on an upper surface of the person's head. In some embodiments, the second set of electrode elements is positioned immediately below the base of the neck.