V11-01: Real-Time Image Guided Focal Surgical Resection for Prostate Cancer: A Feasibility Study

V11-01: Real-Time Image Guided Focal Surgical Resection for Prostate Cancer: A Feasibility Study

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INTRODUCTION

Focal therapy of prostate cancer is a management strategy for localized disease whereby ablative energy is delivered to targeted portions of the prostate to minimize morbidity. The basic tenant of current technologies is that they rely on cellular destruction with no histopathological correlation to ensure completeness and accuracy of treatment. The aim of this experiment was to assess the feasibility of real time MRI/US fusion technology to guide focal surgical therapy of prostate cancer.

METHODS

In a cadaveric model multi-focal prostate cancer was simulated using two 3x1mm MRI-compatible fiducial markers (PolymarkTM from CIVCO medical solution, Coralville, IA, USA) that could not be seen on ultrasound. These were used to generate regions of interests (ROIs) on a 1.5 T surface coil MRI. The first marker was placed in the right peripheral zone at the mid gland (ROI 1) and the second marker was placed in the left seminal vesicle (ROI 2) as a referent for subsequent MRI imaging. A limited multiparametric MRI of the specimen was done after maker placement and following focal surgical excision. The radiologist created ROIs using UroNavTM fusion biopsy system (Invivo, Gainsville, FL, USA) at each marker as well as two additional ROIs that represented intrinsic lesions seen on imaging: the left transitional zone, ROI 3 (suspicious for BPH nodule) and in the right anterior peripheral zone, ROI 4 (suspicious for prostate cancer). The following steps were performed: _x000D_ 1. Holmium laser resection of transitional zone BPH nodule, ROI 3._x000D_ 2. Holmium Laser enucleation of the prostate (HoLEP) to gain access to the peripheral zone._x000D_ 3. Repeat MRI/US fusion imaging to confirm the locations of the remaining ROIs after HoLEP._x000D_ 4. Laser resection of the ROIs 1 and 4. _x000D_ 5. Repeat MRI/US fusion to confirm the absence of the targeted ROIs followed by a final confirmatory MRI_x000D_ _x000D_ Real time MRI/US fusion imaging identified the target lesions consistently at the locations designated as ROIs on the MRI. Using focal surgical therapy it was possible to completely resect each ROI (with the exception of the SV) leaving the majority of the prostate intact. Repeated MRI/US fusion imaging and the post procedure MRI confirmed the complete resection of our targeted lesions. There was no significant fluid extravasation that interfered with successful imaging during the procedure.

RESULTS

Real time MRI/US fusion imaging identified the target lesions consistently at the locations designated as ROIs. Using focal surgical therapy it was possible to completely resect each ROI (with the exception of the SV) leaving the majority of the prostate intact. Repeated MRI/US fusion imaging and the post procedure MRI confirmed the complete resection of our targeted lesions. There was no significant fluid extravasation that interfered with successful imaging during the procedure.

CONCLUSION

Real time MRI/US fusion technology can be used to guide focal surgical therapy of prostate cancer. Additional effort to standardize the procedure and examine the reproducibility is necessary, but this may represent a new frontier for focal surgical resection of prostate cancer.

Funding: none