Prostate cancer ablation

Abstract

Methods and systems for delivering electrical energy and controlled, mild hyperthermia to a prostate tissue of a patient for destruction of cancerous and/or hyperplastic tissue. A method includes positioning a plurality of electrodes in a target tissue region comprising the prostate tissue, and establishing an alternating electrical current flow through a volume of the prostate tissue to induce mild heating and destruction of cancerous cells in the volume.

What is claimed is: 
     
         1 . A method of delivering electric fields to a prostate tissue of a patient, comprising:
 positioning a plurality of a number of electrodes together through an external guide array template to penetrate a target tissue region comprising the prostate tissue, wherein each of the plurality of electrodes is substantially straight, elongated and penetrates and extends through the external guide array template and into the prostate tissue substantially parallel with other substantially straight elongated electrodes of the plurality of electrodes; and   using the plurality of substantially straight elongated and substantially parallel electrodes extending through the external guide array to establish an electrical alternating current flow between the plurality of electrodes in a plurality of different positions and orientations to define a a treatment volume of the prostate tissue,   wherein the alternating electrical current flow further comprises a number of electrical coupling paths having a field strength less than 50 Volts per centimeter between the plurality of electrodes, the number of electrical coupling paths having the field strength less than 50 Volts per centimeter greater than the number of substantially straight and substantially parallel elongated electrodes extending through the external guide array template defining the treatment volume, so as to preferentially ablate one or more of cancerous or hyperplasic cells compared to healthy cells in the treatment volume.   
     
     
         2 . The method of  claim 1 , wherein establishing the electrically alternating current flow comprises applying an alternating electrical current to the volume to provide an electric field extending radially outward from a current flow center. 
     
     
         3 . The method of  claim 2 , wherein the electric field extending radially outward from a current flow center is established by the plurality of electrodes positioned to define an ablation volume, with the plurality of electrodes positioned around the volume activated in groups to establish current flow between the plurality of electrodes. 
     
     
         4 . The method of  claim 1 , further comprising positioning a plurality of secondary electrodes to at least partially define an ablation volume comprising the target tissue region, positioning a center electrode within the ablation volume, and establishing a current flow field between the center electrode and the secondary electrodes extending radially outward from a current flow center. 
     
     
         5 . The method of  claim 1 , wherein positioning the plurality of electrodes comprises advancing a probe comprising the plurality of electrodes to the target tissue region. 
     
     
         6 . The method of  claim 5 , wherein the probe is advanced through a surgical incision, a percutaneous puncture, a perineal, a transurethral, or transrectal access procedure. 
     
     
         7 . The method of  claim 1 , wherein the plurality of electrically alternating current flows heats the target tissue region to an average temperature from about 40 degrees C. to about 48 degrees C. 
     
     
         8 . The method of  claim 1 , further comprising surgically removing at least a portion of the prostate or performing a brachytherapy procedure following electric-current delivery. 
     
     
         9 . The method of  claim 1 , further comprising monitoring a patient's PSA level following electric current delivery to detect prostate tissue ablation. 
     
     
         10 . The method of  claim 1 , wherein the positioning comprises positioning electrodes in the prostate tissue and adjacent to or around the urethra of the patient for treatment of benign prostatic hyperplasia (BPH). 
     
     
         11 . The method of  claim 1 , comprising delivering electrical current substantially throughout the volume of the patient's prostate during treatment. 
     
     
         12 . The method of  claim 1 , comprising maintaining for a period of treatment an average target tissue region temperature below 50 degrees C. 
     
     
         13 . The method of  claim 1 , comprising maintaining for a period of treatment an average target tissue region temperature from about 40 degrees C. to about 48 degrees C. 
     
     
         14 . The method of  claim 1 , comprising maintaining for a period of treatment an average target tissue region temperature from about 42 degrees C. to about 45 degrees C. 
     
     
         15 . A system for preferential destruction of cancerous or hyperplastic cells of a prostate tissue of a patient, comprising:
 an external guide array template;   a plurality of a number of electrodes arranged for advancement and positioning together through the external guide array template into a target tissue region of the prostate tissue, wherein each of the plurality of electrodes is substantially straight, elongated and sized and shaped to penetrate and extend into the prostate tissue substantially parallel with other substantially straight electrodes of the plurality of electrodes;   wherein the external guide array template comprises guides sized and shaped to receive the plurality of electrodes and position the electrodes in tissue in a substantially parallel arrangement to define a treatment volume;   a control system comprising a power source coupled to the electrodes, and a computer readable storage media comprising instructions that ;  when executed, cause the control system to:
 provide electrical alternating current to the plurality of electrodes so as to establish an alternating current flow in a plurality of different positions and orientations between the plurality of electrodes through a treatment volume of the prostate tissue, 
 wherein the alternating electrical current flow further comprises a number of electrical coupling paths having a field strength less than 50 Volts per centimeter between the plurality of electrodes, the number of electrode coupling paths having the field strength less than 50 Volts per centimeter greater than the number of substantially straight and substantially parallel elongated electrodes extending through the guide array template defining the treatment volume, so as to preferentially destroy one or more of the cancerous or hyperplastic cells compared to healthy cells in the treatment volume. 
   
     
     
         16 . The system of  claim 15 , herein the plurality of electrodes comprises three or more secondary electrodes positioned to at least partially define an ablation volume and a center electrode within the ablation volume, the plurality of electrodes positioned such that during energy application a current flow field is established between the center electrode and the secondary electrodes extending radially outward from a current flow center. 
     
     
         17 . The system of  claim 16 , wherein the plurality of electrodes is coupled to a housing of a probe in a fixed position. 
     
     
         18 . The system of  claim 15 , further comprising a feedback unit for detecting temperature in the target tissue region. 
     
     
         19 . The system of  claim 18 , wherein the control nit and feedback unit are coupled so as to maintain an average target tissue region temperature from about 40 degrees C. to about 48 degrees C. during treatment comprising energy delivery. 
     
     
         20 . The system of  claim 15 , further comprising an imaging system. 
     
     
         21 . A method of delivering electric fields to a prostate tissue of a patient, comprising:
 positioning a plurality of a number of electrodes together through an external guide array template to penetrate a target tissue region comprising the prostate tissue, wherein each of the plurality of electrodes is substantially straight, elongated and penetrates and extends into the prostate tissue spaced laterally and substantially parallel relative to other substantially straight electrodes of the plurality of electrodes, and wherein the plurality of electrodes defines a treatment volume in the prostate tissue; and   using the plurality of electrodes to establish an alternating electrical current flow in a plurality of different positions and orientations between the plurality of electrodes through the treatment volume of the prostate tissue,   wherein the alternating electrical current flow further comprises a number of electrical coupling paths having a field strength less than 50 Volts per centimeter between the plurality of electrodes, the number of electrical coupling paths having the field strength less than 50 Volts per centimeter greater than the number of substantially straight and substantially parallel elongated electrodes extending through the guide array template defining the treatment volume, so as to induce mild hyperthermic heating of the treatment volume and preferentially destroy one or more of cancerous cells or hyperplasic cells compared to healthy cells in the treatment volume.   
     
     
         22 . The method of  claim 1 , wherein using the plurality of electrodes comprises differentially activating in seriatim (a) a first activation configuration of the plurality of electrodes so as to induce a first voltage field with a first orientation at a first location within the volume; and (b) a second activation configuration of the plurality of electrodes so as to induce a second voltage field with a second orientation at the location, the second orientation different from the first orientation at the location. 
     
     
         23 . The method of  claim 1 , wherein the plurality of electrically alternating current flow heats the target tissue region to an average temperature of no more than about 50 degrees C. 
     
     
         24 . The system of  claim 15 , wherein the control system is configured to differentially activate in seriatim (a) a first activation configuration of the plurality of electrodes so as to induce a first voltage field with a first orientation at a first location within the volume; and (b) a second activation configuration of the plurality of electrodes so as to induce a second voltage field with a second orientation at the location, the second orientation different from the first orientation at the location. 
     
     
         25 . The system of  claim 15 , wherein the control unit and feedback unit are coupled so as to maintain an average target tissue temperature of no more than about 50 degrees C. during treatment. 
     
     
         26 . The method of  claim 21 , wherein using the plurality of electrodes comprises differentially activating in seriatim (a) a first activation configuration of the plurality of electrodes so as to induce a first voltage field with a first orientation at a first location within the volume; and (b) a second activation configuration of the plurality of electrodes so as to induce a second voltage field with a second orientation at the location, the second orientation different from the first orientation at the location. 
     
     
         27 . The method of  claim 21 , wherein the mild hyperthermic heating includes heating the treatment volume to an average temperature of no more than about 50 degrees C.