Medical probe kits and methods for treating tissue regions (e.g. tumors) are provided. The kit comprises a delivery cannula and an ablation probe. The delivery cannula comprises a shaft, a lumen extending through the shaft, and a plurality of windows formed through a wall of the shaft in communication with the cannula lumen. The ablation probe is configured to be removably disposed within the cannula lumen. The ablation probe has a shaft and proximal and distal arrays of electrodes that are deployable from the probe shaft. The electrodes of the proximal array are configured to be deployed out from the respective windows when the ablation probe is disposed within the cannula lumen. The electrodes of the distal array may be configured to be deployed out from an axial opening at the distal end of the cannula shaft when the ablation probe is disposed within the cannula lumen. The method may comprise introducing the cannula within a patient, introducing the ablation probe through the cannula, deploying the electrode arrays into contact with the tissue region, and conveying ablation energy to the ablation probe to ablate the tissue region within the electrode arrays.
