Urology & Kidney Disease News Fall 2009 - Cleveland Clinic

26 Urology & Kidney Disease News
Prostate Cancer
Establishing Treatment Success Criteria for Cryosurgical
Ablation of Prostate Cancer: An Analysis of the COLD Registry
David Levy, MD
Cryosurgical ablation of prostate cancer is being utilized
more frequently across the country as a minimally invasive
approach to the disease. While biochemical standards of
prostate cancer treatment success have been established for
patients undergoing radiation therapy and surgical extirpation,
no such criteria exist for the cryosurgical population.
In the 2008 publication of “Best Practice Statement on Cryosurgery
for the Treatment of Localized Prostate Cancer” by
the American Urological Association, there were no data by
which the panel could make a statement about end points
by which cryosurgical treatment success could be measured,
demonstrating an urgent need for our recent investigations.
We embarked upon establishing such criteria from an
evidence-based approach. The Cryo On-Line Data (COLD)
Registry provides the potential for comprehensive data analysis
of cryosurgical outcomes. We queried the database in an
effort to correlate nadir PSA levels with biochemical diseasefree
survival based upon “Phoenix” (nadir + 2) criteria in a
risk-stratified population of primary cryoablation patients.
We stratified 2,427 primary whole-gland cryoablation patients
into low-, intermediate- and high-risk based upon the
2003 D’Amico criteria. The cohort was then sub-stratified
into post-treatment PSA reference ranges, < 0.1 ng/ml, 0.1-0.5
ng/ml, 0.6-1.0 ng/ml and 1.1-2.5 ng/ml. Kaplan Meier plots
were constructed and populated with available PSA data out
to 60 months post cryoablation.
Data analysis revealed no significant differences in age, PSA
at diagnosis or Gleason score between the specific PSA reference
range groups. Results for patients with initial PSA of <
0.1 ng/ml and 0.1- 0.5 ng/ml are detailed in the Kaplan Meier
plots and accompanying tables.
A total of 191 patients had an initial post cryoablation PSA
of 0.6 – 1.0 ng/ml. Within this subgroup the 6-, 12-, and
24-month biochemical disease-free survival was low-risk:
100%, 83% and 70.5%, respectively; intermediate-risk: 95%,
81% and 56%, respectively; and high-risk: 92%, 74% and 46%,
respectively. PSA levels of 1.1 – 2.5 ng/ml were associated
with 12-month failure rates in low-, intermediate- and highrisk
groups of 29.6%, 38% and 74.8%, respectively.