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Updated: Aug 11, 2026

Focal Laser Ablation of Prostate Cancer: An Office Procedure
Published on: March 30, 2021
Prostate carcinoma: MR imaging findings after cryosurgery
C L Kalbhen1, H Hricak, K Shinohara
1Department of Radiology, University of California, San Francisco 94143, USA.
Purpose:
To determine the morphologic changes in the prostate gland after cryosurgery and to assess the value of magnetic resonance (MR) imaging in detecting residual tumor.
Materials And Methods:
Twenty-seven patients with prostate carcinoma underwent endorectal MR imaging after cryosurgery. Eighteen patients also underwent MR imaging before cryosurgery. MR findings were correlated with posttreatment clinical data, prostate-specific antigen level, and biopsy results.
Results:
Mean prostate volume had decreased by 52% in patients examined 8 weeks or more after cryosurgery. Zonal differentiation was lost in 22 of 27 patients (81%). Areas of intraprostatic necrosis were identified in 14 of 27 patients (52%). A thick capsule enveloped the gland and neurovascular bundles in 24 of 27 patients (89%). Osteonecrosis of the symphysis pubis was seen in six of 27 patients (22%). Positive and negative predictive values for MR assessment of recurrent tumor were 44% and 73%, respectively.
Conclusion:
Cryosurgery-induced changes in the prostate gland preclude reliable detection of residual prostate carcinoma at MR imaging.

