Focal therapy using magnetic resonance image-guided focused ultrasound in patients with localized prostate cancer

The purpose of this study is to evaluate and report the feasibility, safety, and initial outcomes of patients with limited localized prostate cancer treated using a trans-rectal magnetic resonance image-guided focused ultrasound (MRGFUS) device. Attempts to focally treat only the index lesion for prostate cancer have been explored to reduce side effects while maintaining oncologic control. MRGFUS allows for precise targeting of thermal ablative therapy with real-time thermometry.

Three patients underwent multiparametric 3T MRI and TRUS-guided 16-sector mapping biopsies of the prostate. The patients were eligible if they had Gleason 6 or 7 (3 + 4) disease, no MRI-visible tumor ≥15 mm, no extracapsular extension, and no more than two discrete cancerous lesions ≤10 mm in length. Acoustic power was adjusted to achieve temperatures of 65 to 85 °C.

Age ranged from 60 to 64 years. The number of biopsy-positive sectors treated ranged from 2 to 4. Post therapy, 16-sector biopsies at 6 months were negative in two patients with one patient still with Gleason 6 cancer (10 %, 2 mm) in one core. 16-sector biopsy in the first patient remains negative at 24 months. PSA continues to remain stable in all patients. IPSS in all patients either remained stable or decreased then stabilized. Erectile function according to the International Index of Erectile Function (IIEF) was excellent for all patients and demonstrated no decline up to the time of last follow-up at 12-24 months.

MRGFUS is a feasible alternative for focal therapy in a select subset of patients with prostate cancer. The treatment is well tolerated with no evidence of decline in functional outcomes. Initial post-therapy biopsy results are promising. Long-term treatment efficacy requires further study.