Hemi-gland Cryoablation of Prostate Cancer: Use of MRI-guided Biopsy for Evaluation and Follow-up
Cryoablation was the first of the prostate focal therapies, but follow-up via MRI-guided biopsy has not been reported. In the COLD registry, even conventional follow-up biopsy was not often employed (BJU 113: 14, 2012). Hemi-gland treatment, readily achievable with cryotherapy, offers the potential for effective margins of ablation. We studied safety and cancer-control of hemi-gland cryoablation, using MRI-guided biopsies before and after treatment.
25 men with prostate cancer (CaP) were subjects of this open-label IRB-approved study. Average age = 68 +/- 5.5 y.o., 80% were Caucasian; median prostate volume = 29 cc (IQR = 24, 55), PSA = 6 ng/ml (5.5, 8.3), PSAD = 0.22 (0.16, 0.26). 14 patients had GS = 3+4; 6 had GS 4+3; 3 had high-volume GS6 and 2 had GS = 4+4; pre-treatment MRI-guided biopsy confirmed the lesion to be localized to one side of the prostate. Hemi-gland cooling was achieved via 14ga needles inserted trans-perineally under US guidance, using two cycles of argon gas cooling (Galil/BTG) and a urethral warming catheter. The aim of treatment was complete ablation of the affected side. All patients were treated under general anesthesia in the UCLA surgi-center and discharged the same day with an indwelling Foley catheter; in 10, follow-up with MRI-guided biopsy was available at 6 months.
Cryotherapy was completed satisfactorily in all 25 cases in ≤ 90 minutes (2 or 3 needles) with no intra-operative complications. Treatment related complications in the 25 men included one case of transient urinary retention; no incontinence or erectile dysfunction was seen. At 6 months MRI showed disappearance of the MRI lesion in 6/9 men; extensive biopsy (avg 6 cores from original target, 11 ipsilateral total) revealed no cancer in 6/10, microfocal residual in 2/10, and tumor volume reduction in 2/10 (Chart, Figure).
Hemi-gland cryoablation for intermediate risk prostate cancer is well-tolerated, and when evaluated at 6 months by MRI/US fusion biopsy, has promising efficacy.
Funding: NIH (R01 158627), Jean Perkins Foundation, and UCLA CTSI (UL1TR000124)