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Salvage Cryotherapy
For Recurrent Prostate Cancer After Radiation Therapy.
Recent improvements in
technique have upgraded the performance and outcome of cryotherapy to
become a reasonable salvage option for carefully selected patients
failing primary radiotherapy for prostate cancer. Follow-up for
cryotherapy as primary therapy for newly diagnosed
patients, especially follow-up for patients who have undergone treatment
with "3rd generation" technique, is too short to usefully compare
primary cryotherapy outcomes to the 15+ year data for the three major
treatment modalities. However, cryotherapy as salvage after radiation
failure is emerging to fill a special niche where currently the only
available options are watchful waiting, hormone deprivation, or salvage
prostatectomy with its well recognized technical challenges and high
complication rate.
3rd generation
technique utilizes gas driven ultra-thin 17G cryoprobes (1.5 mm.), first
introduced in 1997, which allow the direct transperineal penetration of
up to 15 probes guided by a template similar to those used in
brachytherapy. This 3rd generation evolution employs argon gas for the
freezing cycle and helium for thawing, as opposed to liquid nitrogen as
used in 2nd generation technique. Two freeze/thaw cycles are used, and
tissue is cooled to a minimum of < 40 degrees C. for at least 3 minutes,
followed by a rapid thaw. These recent improvements build on the prior
development of TRUS guidance, which allows close real-time monitoring of
probe placement, visualization of the rectum, and real-time control of
the size of the ice ball. Urethral warming techniques were developed
which significantly reduced the incidence of urethral sloughing. Pre-cryotherapy
androgen deprivation is generally used to shrink prostates larger than
40 cc., and special maneuvers may be employed to assure optimal
treatment to the apices of especially long glands (> 27 cm.).
Thermocouples monitor the temperatures at the neurovascular bundles to
assure adequate freezing, which is a requisite of success, and
unfortunately nearly always (90% to 100%) leads to impotence. The major
researchers cited in this article advise against cryotherapy for potent
men who wish to maintain performance. Salvage cryotherapy after
permanent seed brachytherapy presents a special difficulty for TRUS
interpretation due to conflicting echoes arising from the indwelling
seeds. In selected cases cryotherapy may be repeated.
Because the 3rd
generation techniques promise improvements in outcome and reduction in
morbidity compared to earlier procedures, it is appropriate to restrict
current analysis to those reports incorporating the most recent
developments. And since new developments in this field are rapidly
emerging, any reports must be viewed as initial and preliminary data in
this evolving field.
"Salvage Cryotherapy
for Recurrent Prostate Cancer After Radiation Therapy: A Seven-Year
Follow-up" (Bahn et.al, Clinical Prostate Cancer, Sept. 2003) reports on
a retrospective analysis of outcome and morbidity in 59 men, clinical
stage T1-T3, with biopsy proven recurrence treated with 3rd generation
technique. The threshold for recurrence was set at PSA >0.5 ng/mL. 69%
had Gleason scores of < 7; 36% had a PSA values < 4 ng/mL and 41%
had PSA values between 4 and 10. The clinical stage was T2 in 63% of
men, the remaining being T3 or T4. The median F/U after cryotherapy was
82 months. In their study group the bDFS was 61%, 68%, and 61% for low,
intermediate, and high-risk patients. The reported incontinence rate was
4.3% and rectal fistula formation, 3.4%. In the opinion of these authors
the optimal candidates are men with PSA < 10 whose pre-RT clinical
stages was T1 or T2.
[Editorial note:
Although the small numbers and short duration of F/U for men treated
with 3rd generation cryotherapy technique prevents acquiring the
required comparable data, none the less there is no reason to think that
the degree of success for salvage cryotherapy would not be determined by
the same parameters (pre-treatment Gleason score and PSA, and rate of
PSA rise) that select for the optimal results for RT salvage after RP.]
Han et.al (UCLA) in
"Third-generation cryotherapy for primary and recurrent prostate
cancer", BJU Int, 93: pp. 14-18, 2004, reported on 29 men who had
undergone salvage cryotherapy. Seven percent reported the use of pads
and none had recto-urethral fistulae. Ghafar (J. Urol 2001), using the
argon system for locally recurrent prostate cancer after radiotherapy,
reported follow-up data on 38 men with biopsy proven recurrent prostate
cancer after radiation therapy failed (PSA > 0.3 ng/mL above post-RT
nadir). Biochemical RFS was 86% at one year and 74% at 2 years. 86% of
their patients had a PSA of < 0.1 ng/mL at a mean F/U of 20
months. Complications included rectal pain, 39.5%; incontinence 7.9%;
and scrotal edema, 10.5%. There were no instances of rectourethral
fistula or urethral sloughing.
Perspective on the
pathologic outcome of cryotherapy was provided by Chin, "Serial
Histopathology Results of Salvage Cryoablation For Prostate Cancer After
Radiation Failure", J Urol Oct. 2003. Fifteen of 106 patients (14.2%)
were found to have positive biopsies, 73.9% of which were found within
one year following cryoablation. Han regarded this result acceptable,
but "vigilant long-term" follow-up was warranted.
Bahn concluded "that
his data further supports cryoablation as a safe and efficacious salvage
treatment for radiation-resistant prostate cancer with durable results".
Although Han acknowledged that longer term F/U is needed ,he offered the
opinion that "in patients who present after failure of radiation therapy
... salvage cryotherapy may offer a more attractive alternative than
salvage prostatectomy, hormone deprivation, or watchful waiting".
Bottom Line:
Salvage cryotherapy with 3rd generation technique has become a
reasonable treatment option for carefully selected men who have
biochemical failure after primary radiotherapy.
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