Cancer cells can be synchronized to the G2/M phase by delivering an anti-microtubule agent (e.g., paclitaxel or another taxane) to the cancer cells, and applying an alternating electric field with a frequency between 100 and 500 kHz to the cancer cells, wherein at least a portion of the applying step is performed simultaneously with at least a portion of the delivering step. This synchronization can be taken advantage of by treating the cancer cells with radiation therapy after the combined action of the delivering step and the applying step has increased a proportion of cancer cells that are in the G2/M phase. The optimal frequency and field strength will depend on the particular type of cancer cell being treated. For certain cancers, this frequency will be between 125 and 250 kHz (e.g., 200 kHz) and the field strength will be at least 1 V/cm.
