The following article appeared on Medscape yesterday (1/10/06)
Dr.Mulhall is head of the Sexual Medicine program at Cornell/SKM in
NYC. I consider him an expert's expert. Enjoy.
Steve U

Sexual Dysfunction After Radical Prostatectomy: Recent Studies
John P. Mulhall, MD
Even in its nerve-sparing form, radical prostatectomy (RP) is
associated with a number of sexual dysfunctions including erectile
dysfunction (ED), anejaculation, orgasm-associated incontinence
(climacturia), Peyronie's disease, and penile length changes. The
presence of 1 or more of these conditions is often associated with
significant reductions in the quality of life of the patient and his
partner.
It is well established that 2 major patient populations with high risk
of ED have a reduced ability to respond to PDE5 inhibitors: men with
diabetes and men who have undergone radical prostatectomy. Bennett and
colleagues[1] reported the results of an uncontrolled study on the
effectiveness of sildenafil after RP. In 187 patients who had
functioning erections before surgery (average patient age was 58 years)
statistical analysis demonstrated significant improvement in sildenafil
response over the first 18 months after radical prostatectomy. At 18
months post-RP, 52% of men had functioning erections, and significant
predictors of failure to respond to sildenafil post-RP were older age
(patients = 60 years), having more than 2 vascular comorbidities
(diabetes, hypertension, dyslipidemia, cigarette smoking), early stage
after surgery (= 6 months). The major take-home message from this
paper was that patients who fail sildenafil early after RP should be
re-challenged on a regular basis after surgery as the time to optimal
response appears to be more than 18 months after surgery.
Nelson and coworkers[2] assessed predictors of sexual satisfaction in
men with prostate cancer. In a database of 352 men with early and
late-stage prostate cancer, satisfaction and erectile function were
assessed by questionnaire. Patients were also questioned regarding
anxiety and depression. The average patient age was 67 years old. Older
patient age and the presence of depression and anxiety were associated
with a significant reduction in satisfaction while good erectile
function was associated with higher levels of satisfaction. Of all
predictive factors, erectile function was identified as the strongest
predictor.
There is accumulating evidence that the presence of blood flow
abnormalities in the penis after RP is a predictor of long-term ED
after radical prostatectomy. Ohebshalom and colleagues[3] analyzed the
significance of post-RP penile blood flow in the prediction of
long-term erection function. The study involved assessment of men after
RP who had penile blood flow measured (by Doppler penile ultrasound)
within 6 months of surgery. All men had functioning erections
preoperatively based on self-report. There were a total of 111
patients, with an average age of 57 years. Twenty-nine percent of
patients were found to have normal postoperative penile blood flow,
while 71% had abnormal penile blood flow. Fifteen percent were found to
have a component of venous leak, a significant predictor of failure to
obtain functioning erections after RP with or without PDE5 inhibitors.
There were significant differences between those men with normal and
abnormal penile blood flow in erection function scores, erection
hardness, and percent of patients responding to sildenafil after RP.
These data support the accumulating evidence that blood flow changes
that occur at the time of surgery or early after RP are predictive of
erection function recovery.
Much has been written about the topic of penile rehabilitation after
RP. Post-RP rehabilitation has taken numerous forms, including the use
of chronic PDE5 inhibitors, intracavernosal injections, vacuum device
therapy, or a combination of all of the above. Wang and colleagues[4]
presented data on the compliance of patients in a formal rehabilitation
program. This study was conducted as part of larger trial on the
effectiveness of unilateral cavernous grafting at the time of RP.
Penile rehabilitation was initiated 6 weeks postoperatively with a
vacuum erection device (VED), intracavernosal injection (ICI), and the
use of sildenafil. Compliance was evaluated by assessing the number of
times/week that VED or ICI was performed. A total of 100 patients were
enrolled in the study. At 4, 8, and 12 months after RP, 73%, 67%, and
47%, respectively, of patients were continuing to comply with vacuum
therapy; at 4, 8, and 12 months after RP, 52%, 26%, and 35% continued
to use injections. In this study, older patients were more compliant
than younger ones. These data indicate that even in a formally
structured rehabilitation program, patients drop out as time passes.
RP may be associated with loss of penile length and volume. Huber and
coworkers[5] reported on penile length after RP. As part of a larger
study assessing the effectiveness of cavernous nerve grafting, a total
of 65 men had penile rehabilitation initiated 6 weeks postoperatively
consisting of daily use of the VED, biweekly ICI, and patient-directed
use of sildenafil. Penile length was measured preoperatively, at 6
weeks, and every 4 months up to 2 years after surgery. Of the 39
patients reported on in this interim analysis, 25 received unilateral
sural nerve grafting and unilateral nerve-sparing prostatectomy while
14 patients received a unilateral nerve-sparing prostatectomy alone.
Patients who had return of erectile function had a significant
preservation of penile length at 12 months compared to 6 weeks
postoperatively. At 12 months, the mean improvement in penile length
from the 6-week measurement for patients who were potent was 1.2 cm.
Patients who had not regained erectile function showed an increase of
only 0.2 cm. The difference between these 2 groups was statistically
significant.
Orgasm-associated incontinence, also termed climacturia, has been
receiving increasing attention in the medical literature. It can have a
significantly negative impact on a man's and his partner's sexual
satisfaction. Abouassaly and coworkers[6] reported their findings with
men who had climacturia after having undergone RP. Of an estimated 220
patients evaluated, 26 men experienced urine leak almost exclusively at
the time of orgasm. The average age of the patients was 62 years. There
was no clear association with degree of nerve sparing or daytime
continence level. Patients experienced anywhere from 3 to 120 mL of
urine leak (by patient self-report) at the time of orgasm. The authors
feel that the occurrence of ejaculatory incontinence high enough for it
to be considered as part of the routine post-prostatectomy evaluation.
The results from studies using animal models to assess the use of drugs
for erection nerve protection were presented. Minor and colleagues[7]
from the University of California-San Francisco presented their data on
a novel compound called FK1706 (a derivative of the available drug,
FK506 currently in trials for this indication). This drug is different
from FK506 in not being an immunosuppressant. FK1706 facilitated
erection recovery with penile pressures 4 times higher in the high-dose
FK treatment group compared to the group without the use of FK1706.
Kendirci and coworkers[8] evaluated the compound Ino-1001 as a
protectant of erection nerves. They demonstrated that animals treated
with the compound had a significant increase in erection function
compared to those not treated. Lehrfeld and colleagues[9] looked at the
combination of sildenafil and FK506 in rats that underwent nerve crush
injury. A course of combined sildenafil and FK506 treatment after
cavernosal nerve injury had the maximum positive effect on erectile
function recovery. However, sildenafil alone also appeared to exert a
protective effect on erectile function.
References
1.    Bennett N, Parker M, Donohue J, Mulhall J. Sildenafil following
radical prostatectomy: chronology and predictors of response. Program
and abstracts of the Sexual Medicine Society of North America Fall
Meeting; November 17-20, 2005; New York, NY. Abstract 11.
2.    Nelson C, Roth A, Mulhall J. Correlates of sexual satisfaction in
men with prostate cancer. Program and abstracts of the Sexual Medicine
Society of North America Fall Meeting; November 17-20, 2005; New York,
NY. Abstract 113.
3.    Ohebshalom M, Mulhall J, Flanigan R, Waters W, Parker M. Erectile
hemodynamic status following radical prostatectomy correlates with
erectile function outcomes. Program and abstracts of the Sexual
Medicine Society of North America Fall Meeting; November 17-20, 2005;
New York, NY. Abstract 117.
4.    Wang R, Huber N, Madsen L, Wood C, Babaian R. Long term compliance
to penile rehabilitation program following radical prostatectomy.
Program and abstracts of the Sexual Medicine Society of North America
Fall Meeting; November 17-20, 2005; New York, NY. Abstract 156.
5.    Huber N, Wood C, Babaian R, et al. Recovering penile length and
erectile function following radical prostatectomy. Program and
abstracts of the Sexual Medicine Society of North America Fall Meeting;
November 17-20, 2005; New York, NY. Abstract 60.
6.    Abouassaly R, Lane B. Lakin M, Klein E, Gill I. Ejaculatory
incontinence after radical prostatectomy: a review of 26 cases. Program
and abstracts of the Sexual Medicine Society of North America Fall
Meeting; November 17-20, 2005; New York, NY. Abstract 1.
7.    Minor T, Bella A, Carrion R, Price R, Lue T. The effect of FK1706 on
erectile function following a bilateral cavernous nerve crush injury in
a rat model. Program and abstracts of the Sexual Medicine Society of
North America Fall Meeting; November 17-20, 2005; New York, NY.
Abstract 10.
8.    Kendirci M, Zsengellér Z, Szabo C, Hellstrom W. Cavernosal
neuroprotection with Ino-1001 in a rat model of postprostatectomy
erectile dysfunction. Program and abstracts of the Sexual Medicine
Society of North America Fall Meeting; November 17-20, 2005; New York,
NY. Abstract 70.
9.    Lehrfeld T, Lagoda G, Burnett A. An early course of sildenafil and
FK506 treatment on erectile function after cavernous nerve injury.
Program and abstracts of the Sexual Medicine Society of North America
Fall Meeting; November 17-20, 2005; New York, NY. Abstract 85.