Indication for Prostate Biopsy following Primary Total Surgical Cryoablation of the Prostate: Sensitivity of ASTRO Criteria
Martyn Vickers, Jr., MD, Elizabeth Tulip, PA-C.
Penobscot Bay Medical Center, Rockport, ME, USA.
Indications for Prostate Biopsy following Primary Total Surgical Cryoablation of the Prostate: Sensitivity of ASTRO Criteria
Objective: Presently, there are no generally accepted indications for prostate biopsy following total cryoablation of the prostate. Our objective was to assess the positive predictive value of the ASTRO Criteria (three successive increases in PSA from the nadir value) in the detection of residual prostate cancer by prostate biopsy following total surgical cryoablation of the prostate.
Method: Between December 2006, and October 2007, 30 patients with localized high (T1C, 2A, 3, N0, M0, PSA <10 ng/ml), intermediate, and low risk prostate cancer underwent total surgical cryoablation of the prostate. PSA assays were obtained immediately prior to surgery and at 6 weeks and then every 3 months post-operatively for one year. Patients with three consecutive increases in PSA above the nadir value during the first post-operative year underwent repeat prostate biopsy. High-risk patients who met ASTRO Criteria had repeat post-cryo CT and bone scans.
Results: The mean PSA at one year for the nine high, ten intermediate, and eleven low-risk patients was 0.72, 0.3, 0.34 ng/ml, respectively. All 4 patients who fulfilled the ASTRO criteria had a PSA of 1 or greater at one year and PSA velocity of greater than 0.5 ng/ml/y. Two of three high-risk patients had residual cancer on repeat biopsy. One patient with intermediate risk disease had a positive biopsy. None of the low risk patients met the ASTRO criteria or had a PSA that equaled or exceeded 1 ng/ml or a PSA velocity of greater than 0.5 ng/ml, and none were re-biopsied. None of the repeat post-cryo CT and bone scans in the high risk patients detected metastatic disease.
Conclusion: Within the one year post-operative period, repeat prostate biopsies based on the ASTRO criteria or a Critical PSA value of 1 ng/ml or a PSA velocity of greater than 0.5 ng/ml/y were equally sensitive in accurately predicting residual localized prostate cancer.