A margin extension device and method are disclosed herein. The margin extension device can be used for ablating one or several cancer cells and can include a contact member and a plurality of electrodes. The contact member can be electrically conductive, and can electrically connect the electrodes. The margin extension device can further include one or several leads that connect the electrodes of the margin extension device to a treatment controller. The treatment controller can include a pulse generator that can generate one or several electrical pulses that generate one or several electrical fields in tissue proximate to the margin extension device.