UroToday.com – This type of trial is very difficult to conduct, resulting in slow accrual, and ultimately, early closure. Thus the study is underpowered. Other shortcomings are pointed out in our discussion.
As an equivalence study, it meets the 4 criteria for such an undertaking:
- margin clearly stated initially
- sample size indicated
- reported on an intention to treat (ITT) basis, and
- confidence intervals reported
The results are presented very clearly and openly, and the data is clean.
While there is no difference between arms at 36-month follow-up, there is a clear trend in favour of Cryo with time. This is seen at 5 years using the original biochemical failure definition (PSA > 1.0), and at 7 years using the new ASCO definition (Nadir + 2).
Fourteen patients underwent repeat Cryo more than 6 months after initial treatment and are all counted as failures. In fact, 6 of these patients remain disease free 7 to 9 years later. As a clinician, I consider these treatment successes. If these cases are counted in the Cryo arm as successes, then the difference between treatments is more pronounced.
It is very unlikely that this work will be duplicated.
Written by Bryan J. Donnelly, MCh as part of Beyond the Abstract on UroToday.com. This initiative offers a method of publishing for the professional urology community. Authors are given an opportunity to expand on the circumstances, limitations, etc., of their research by referencing the published abstract.
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