The
National Institute for Clinical Excellence in Britain is examining cryotherapy
as a treatment option for prostate cancer and will publish guidance on its safety
and efficacy to the NHS in England, Wales and Scotland. The Institute's Interventional
Procedures Advisory Committee has considered the available evidence and the views
of Specialist Advisors, who are consultants with knowledge of the procedure. The
Advisory Committee has made provisional recommendations about cryotherapy for
prostate cancer. This document summarises the procedure and sets out the provisional
recommendations made by the Advisory Committee. It has been prepared for public
consultation and can be accessed here.
This
extract from the document summarises the views of the Advisory Committee on the
Efficacy and Safety of the procedure:
EFFICACY
Prostate-specific antigen (PSA) is a protein produced by both normal and
cancerous cells in the prostate gland. Reduction in the PSA level may be used
to monitor response to treatment and, along with negative biopsies, is used as
a surrogate marker for improved clinical outcomes in trials of salvage cryotherapy.
Various efficacy outcome measures were used in the studies identified, making
comparisons of efficacy across studies difficult.
In one study, nadir
PSA < 0.5 ng/ml was reported in 97% (114/118) of patients who had undergone salvage
cryotherapy; in another study, a level of < 0.1 ng/ml was reported in 60% (26/43)
of patients. These studies included patients with recurrent prostate cancer or
rising PSA levels, and those who were undergoing salvage therapy.
In
a study of 43 patients, biochemical-recurrence-free survival (recurrence defined
as an increase in PSA level of >0.2ng/ml above nadir) was reported as 79% at 6
months and 66% at 12 months, and in a study of 38 patients (recurrence defined
as an increase in PSA level of >0.3ng/ml above nadir), as 86% at 12 months and
74% at 24 months. One case series reported negative biopsy in 100% of patients
(38/38) followed up for a median 82 months. Another case series reported negative
biopsies in 79% (87/110) of patients at 6 months follow-up.
SAFETY
Complication rates varied substantially among the studies and there is some
evidence to suggest that complications have decreased with improvements in technique
and instrumentation. Among the studies identified, the following complications
were reported:
impotence in 72% (108/150) and 86% (12/14) of patients:
incontinence in 8% (3/38) of patients;
perineal and/or rectal pain in 18% (27/150) to 39% (15/38) of patients.
Other
reported complications from the case series included fistula formation in 1% (2/150)
to 3% (4/118 and 2/59) of patients.
The Specialist Advisors listed the
main complications as urinary incontinence, impotence, rectal injury and fistula
formation. However, severe complications are rarer and comparison needs to be
made to complication rates in alternative options.
OTHER COMMENTS
In recommending that further research and audit should address long term
survival, the committee noted that prostate cancer patients frequently die from
unrelated causes
It was noted that the technology for this procedure is continuing to evolve.
