Focal Laser Ablation of Prostate Cancer: Results in 120 Patients with Low- to Intermediate-Risk Disease

Abstract

Purpose: Can focal laser ablation (FLA) of low to intermediate risk prostate cancer preserve sexual and urinary function with low morbidity while providing adequate oncologic outcomes.

Materials and methods: Transrectal FLA was done in 120 patients with low- to intermediate-risk prostate cancer. MR imaging thermometry controlled ablation. At 6 and 12 months, patients had clinical and MR imaging follow-up with biopsy of suspicious areas. Patients submitted surveys of sexual and urinary function. Multivariate logistic regression identified determinants of positive imaging and biopsies. Two-sided Wilcoxon signed rank test evaluated scores and laboratory values.

Results: Median patient age was 64 years, and median prostate-specific antigen (PSA) was 6.05 ng/mL. Median follow-up period was 34 months (range, 17-55 months). Gleason score was 3+3=6 in 37 (30.8%), 3+4=7 in 56 (46.7%), and 4+3=7 in 27 (22.5%) patients. Tumor stage was T1c in 89 (74.2%), T2a in 26 (21.7%), and T2b in 5 (4.2%) patients. Twenty (17%) patients had additional oncologic therapy 1 year after FLA when biopsy confirmed cancer following abnormal MR imaging. There was no difference between functional scores before and after ablation. Median PSA decreased to 3.25 at 12 months (P < .001). Tumor diameter above the median (odds ratio = 3.36; 95% confidence interval, 1.41-7.97) was the only significant predictor for positive MR imaging after treatment.

Conclusions: One year after FLA, selected patients had low morbidity, no significant changes in quality of life, and 83% freedom of retreatment rate. Sexual and urinary function did not significantly change after FLA.

Conflict of interest statement

Conflict of interests: All authors have no conflicts of interest.

Copyright © 2019. Published by Elsevier Inc.

Figures

Figure 1.

Consort diagram

Figure 2.

Images of the Technique for Focal Laser Ablation A. The laser fiber (arrow) and the rectal probe were guided to the targeted T2-hypointense tumors using the DynaTRIM Transrectal Interventional MRI system (Phillips®), which gives the rectal probe three planes of position adjustment to guide the laser using mpMR images in any plane. Double arrows point to the inflow and outflow tubing for cooling saline infusion. B. The diffusing laser fiber tip creates a 16 to 18mm oval ablation zone and the laser can be advanced or withdrawn within the cooling cannula to “paint” an ablation zone (arrows point to white area—zone of tissue ablation). The dotted arrow points to the left neurovascular bundle which was monitored during the real-time procedure to avoid nerve involvement in the zone of ablation. C. If the targeted tumor was close to the rectal wall, a sheathed needle was punctured into the rectoprostatic space (also transrectal) and used to hydrodissect the rectum (black arrow) away from the prostate capsule (small white arrow). The saline hydrodissection was bright on T2 imaging and surrounds and protects the rectum (long white arrow). D. Hemiablation of the involved side of the prostate on sagittal T1 weighted images after intravenous gadolinium contrast administration (dark zone outlined by arrows). The dark signal represents avascular, non-viable tissue post FLA.

Figure 3.

Erectile and urinary function after focal laser ablation (FLA). IPSS=International prostate symptom score, SHIM=Sexual health in men score. There was no significant difference in scores before and after FLA over time. IPSS p=0.12 and SHIM p=0.51

Figure 4.

Freedom from needing secondary treatments up to 24 months from ablation (log rank p<0.001).