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Adjuvant
Androgen
Withdrawal
Reprinted from PCRI Insights May
2003 v 6.2
By Glenn Tisman, M.D., Dr. Glenn Tisman
Medical Corporation
Introduction
Early use of hormonal
ablation in prostate
cancer therapy is a controversial issue in the
urological community. This controversy catches
many newly diagnosed patients by surprise.
Patients often think of medicine as black and
white. Disease A receives treatment A, disease B
gets treatment B, and so on.
However, as patients pursue different medical
evaluations, they soon find themselves in a
complex universe of opinions and ambiguities,
and making decisions can be troubling at best.
Some physicians may recommend early hormonal
therapy. Others will reject such treatment
as nonsense. Which is best for the patient? Which opinion best reflects their needs? Which
will extend life? Perhaps extending life is not
all that counts.
I generally reassure newly diagnosed
prostate cancer patients that chances are greater than 90 percent that
their tumor cells will die from the depletion of circulating
blood and tissue of testosterone. The
suppression of blood and tissue testosterone is the most powerful weapon
that a physician has for
the treatment of advanced prostate
cancer. Because testosterone lowering
is
so powerful in advanced disease, many study projects in recent years have
attempted to use this therapy in patients with early, less advanced prostate
cancer.
In this article, I plan to review some important studies that have
evaluated the use of testosterone lowering in the early as well as
late stages of
disease. I will
focus on patients with minimal and locally advanced prostate cancer, and
we will
review testosterone lowering as a definitive
therapy exclusive of other
therapies,
or as an adjuvant therapy to the standard therapies such as radiation and
surgery. Adjuvant
therapies are those directed to destroy any minimal, residual
tumor cells that may have escaped removal or destruction by surgical or
radiation
therapy. It is hoped that through this review of clinical
trials you will
become
empowered with the knowledge necessary to help you and your physician choose
the best therapy for your stage of disease.
Testosterone Lowering: Historical
Perspective
Decades ago, Nobel Laureate Charles Huggins demonstrated that normal
canine prostate tissue required testosterone (a male hormone, also called “androgen”) for growth and development. Since then, withdrawal of
testosterone
has provided the best therapy for patients with advanced prostate cancer.
Normally,
the hypothalamic–pituitary–testicular axis regulates
the synthesis
of testosterone. Think of this axis as a network of hormone-producing
organs that speak to each other, assuring that proper amounts of testosterone
are available
for the maintenance of normal cellular function. Many tissues, e.g. bone,
depend on the presence of testosterone for peak performance but are capable
of
reasonable function without it. Other tissues such as the prostate
gland and
prostate cancer cells cannot live without it.
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Figure 1. The pituitary-hypothalamic axis
of hormone stimulation (fat white arrows) and feedback inhibition
circles with minus signs. |
Approximately eighty-five
percent of the body’s testosterone comes from the testes,
while two small glands that rest atop the kidneys, the
adrenal
glands, produce the remaining fifteen
percent. Testosterone, once synthesized in the
testes or from precursor hormones within the
adrenal glands, undergoes a conversion within
the cells that use the hormone. It becomes dihydrotestosterone (DHT)
by the action of two enzymes called 5-alpha
reductase I (5-AR-I)
and 5-alpha reductase-II (5-AR-II). DHT is four
times as potent as testosterone in producing
masculinizing effects. Once formed, DHT binds
to the cytoplasmic androgen receptor complex
of normal prostate cells and of the prostate cancer
cell. This union prepares DHT for its journey
into the cell nucleus (where chromosomal DNA resides). Once in the nucleus, the complex
binds to nuclear DNA, initiating a process that
ends with the synthesis of various proteins capable
of mediating the biochemical effects of the
hormone (Figures 1 and 2).
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Figure 2: Prostatic Cell Stimulation.
Testosterone is reduced by the 5-alpha reductase enzyme present
in prostate cancer cells. The reduced hormone then binds to
the testosterone receptor for transportation into the cell
nucleus. The bound testosterone-receptor complex next binds
to nuclear DNA (this binding may be modulated by several compounds)
thus inducing new protein synthesis. The synthesized proteins
may have differing androgenic functions. |
Androgen ablation, termed “testosterone
withdrawal”, may be achieved surgically by
removal of both testicles (bilateral orchiectomy)
or pharmacologically, with Lupron® and
Zoladex®. Lupron and Zoladex are two luteinizing
hormone-releasing hormone agonists (LHRH agonists) that initially stimulate a
release, or “surge”, of luteinizing hormone
from the pituitary gland (a small endocrine
gland residing in the base of the skull). The
initial LH surge is responsible for the subsequent
testosterone surge, which may last a
week after initiating the first dose of a LHRH
agonist. This initial stimulation gives way to
prolonged inhibition of LH secretion and testicular
testosterone production, leading to very
low blood and tissue levels of the hormone.
Other hormones and medications
can suppress testosterone levels. The synthetic estrogen,
diethylstilbestrol, reduces testosterone to castrate levels in a dose-dependent fashion (1-3 mg
daily is required). Because levels greater than
0.5-1 mg daily are associated with increased
cardiovascular complications in as high as 20%
of treated patients, it is no longer available in
the United States unless purchased from compounding
pharmacists by prescription.
Other antiandrogen drugs that block androgen
receptors from binding to DHT include
Casodex®, flutamide and nilutamide.
Ketoconazole (Nizoral®) is an anti-fungal drug that as a
side effect directly inhibits androgen precursor
and testicular testosterone production. Ingestion
of large doses of ketoconazole (1200 mg daily) is
the fastest way to achieve castrate levels of testosterone
(within 24 hours) short of surgical
removal of the testicles. When antiandrogens are
used in combination with LHRH agonists, the
treatment is referred to as combined androgen
blockade or combined androgen deprivation
therapy. Some physicians have been adding a
third drug, a 5-alpha reductase inhibitor, called
finasteride,
in an attempt to enhance testosterone deprivation. Though most androgen
deprivation medications have been available for
years, issues relating to the best time to use them
and which doses and combinations of drugs to
use for best results have not yet been resolved.
Animal Studies
Animal models of prostate cancer have been helpful in studying the
effects of various drugs
and hormone therapies on prostate cancer
growth. One such model is the Dunning R-3327
rat model, in which, Isaacs and
co-workers showed that early removal of the testes was associated
with decreased growth of transplanted
prostate cancer cells and increased survival.
Although all animals,
regardless of when orchiectomy was carried out, succumbed to
tumors, this was a landmark study in demonstrating
that early withdrawal of testosterone by
castration could be more beneficial than delayed
withdrawal. This study laid the scientific groundwork
for clinical studies of early androgen withdrawal
in patients with prostate cancer.
Early Human Adjuvant Trials
Medical Research Council Study
The Medical Research Council (MRC) in the
United Kingdom is involved in many large
cooperative group medical research projects,
and it undertook one of the earliest trials of
immediate versus delayed hormonal withdrawal
as treatment for advanced prostate cancer.
The MRC study revealed
significant differences in favor of immediate androgen withdrawal
with respect to disease-free survival
(survival without evidence of prostate cancer)
and overall survival (survival with or without
evidence of prostate cancer). The study group
that was given immediate therapy suffered fewer
major complications, including reductions
in pathologic bone fractures, spinal cord compression
from tumor and paralysis, urethral outlet obstruction (inability to pass urine), and
development of new distant metastases.
This clinical trial, initiated
17 years ago supported the principle of early hormonal withdrawal
for prostate cancer. Interestingly, the
benefit in terms of surviving prostate cancer was
largely seen in patients with locally advanced
disease, but not in those with distant metastases.
This study suggested that adjuvant or early hormonal
ablation is better targeted at patients
with minimal residual disease, as is often present
after definitive surgery or radiation.
Veterans Administration
Cooperative Urological
Research Group (VACURG)
Studies
Three large Veteran Administration Cooperative Urological Research
Group (VACURG) studies,
conducted throughout the 1960s and mid 70s,
established the generally accepted guidelines
for treatment with hormonal therapy for the
70s through the late 80s, and gave further
insight into the role of early hormone therapy
for prostate cancer. The
results of these clinical studies shaped the direction of
further research and standard clinical
urological practice for the next four
decades. Their historical and current importance
demands that we summarize their results.
VACURG #1
The researchers at VACURG first took a group of
stage
I and stage II patients. They were treated with radical
prostatectomy followed by either
no further therapy, or 5 mg daily of the testosterone
suppressing diethylstilbestrol (DES).
Surprisingly, stage I patients who received DES
had a significantly worse overall rate of survival
compared to those who did not receive the
hormone. DES-treated patients suffered from
heart attacks, strokes, blood clots and pulmonary
embolisms (blood clots that spread to
the lungs). Stage II patients had no significant
differences in disease-specific or overall rates of
survival. This study group, in which hormones
were used in a truly adjuvant setting, failed to
demonstrate the benefit in early testosterone suppressing
therapy with DES.
However, the VACURG researchers also studied
patients in the more advanced stages of prostate
cancer (stage III and stage IV). These patients
were treated with placebo, 5 mg DES, orchiectomy
plus placebo, or orchiectomy plus 5 mg DES.
The three hormonal treatment groups had
significantly less disease progression than the
placebo group. However, the delayed progression
did not translate into an overall survival
benefit for these patients. Part of the reason for
that was because of the increased cardiovascular
deaths in the DES groups. Yet even in
groups with no exposure to DES (placebo alone
or orchiectomy plus placebo), the results failed
to translate into decreased progression and
overall survival benefit. This was largely
because the orchiectomy group had multiple
competing, non-cancer-related deaths.
The fact that the observed
delay in progression, including a decrease in prostate cancer death,
did not translate
into a survival benefit
would be noted again in studies to come.
Researchers generally accepted that the
increased cardiovascular mortality and deaths
from other causes in the DES treated group
obviated any appreciable survival benefit by
DES responders. They also considered that any
study group that contained a greater number of
patients with cardiovascular disease would be
expected to do worse than a healthier study
group, regardless of any beneficial effects of
treatment on the prostate cancer.
VACURG #2
The second VACURG study involved stage III
and IV patients. They were given no treatment,
0.2 mg of DES, l mg of DES, or 5 mg of DES
daily. The study ended prematurely because of
unacceptable numbers of cardiovascular
deaths in the 5-mg DES group. However, this
study, similar to VACURG #1, demonstrated that
l mg and 5 mg of DES significantly delayed the
progression of stage III prostate cancer patients
into stage IV patients. It showed that those taking
l mg of DES had a significantly better overall
survival rate than the other groups.
The delayed progression seen
in the group with the largest dose, 5 mg of DES, again did
not translate into a survival benefit because of
the excessive number of cardiovascular deaths.
The study suggested that immediate estrogen
therapy would be most beneficial for younger
patients (younger than 75 years old with higher
Gleason’s score tumors, ranging between 7 to
10), and that a low dose of DES was as effective
and less toxic than the higher dose.
VACURG #3
The third VACURG study gave stage I and II
patients without prior surgery or radiation l mg
of DES, or no therapy. Strangely, DES produced
an excess of cardiovascular deaths in stage I
patients, but not stage II patients. The authors
were unable to account for such results. DES
still decreased progression and increased the
5-year overall survival.
Based on these three studies, some
clinicians found that the benefit of delayed
disease progression in some patient subgroups
provided them with a basis for further
development of the early use of hormonal
therapy as adjuvant therapy for
prostate cancer. Clinicians knew that patient
selection and the use of newer less toxic therapy
would play a key role in the future success of
early hormone withdrawal therapy.
Neoadjuvant Androgen
Deprivation Therapy
Neoadjuvant Therapy and
Surgical Margins
When treatment is applied before definitive radiation
or surgery, it is termed neoadjuvant therapy.
This modality has been quite successful in
patients with breast cancer and helps define
those who will have prolonged survival. Patients
responding thoroughly to neoadjuvant treatment
have invariably enjoyed prolonged survival
when compared to those enjoying only a partial
response. It is not unusual to have all traces of
breast cancer disappear before surgery in
patients treated with neoadjuvant chemotherapy
(17-30% of patients). Neoadjuvant therapy is a
way one can tell early on in the disease whether
a particular patient may need more than usual
therapy and whether the drugs used as neoadjuvant
treatment are effective.
Table 1 reveals results from five studies
of neoadjuvant androgen withdrawal therapy in
prostate cancer patients. Treatment efficacy was
measured by primary tumor shrinkage and the
frequency of positive surgical
margins. A positive
surgical margin means that the entire tumor
could not be surgically removed from the patient.
As can be seen in Table 1, neoadjuvant therapy
significantly decreased the frequency of
positive surgical margins by a factor of 50%
or more. These exciting initial observations have
given way to critical pessimism by some urologists.
The criticism comes from the inability thus
far to demonstrate increased survival for patients
undergoing neoadjuvant therapy. However, since
neoadjuvant protocols are relatively new and the
course of prostate cancer is quite long, some feel
that these study results are premature and may
later demonstrate prolongation of survival in
years to come.
Duration of Neoadjuvant
Therapy
The reported duration of pre-operative or preradiation
neoadjuvant androgen withdrawal
has varied between 3-8 months. A summary of
clinical studies illustrated in Table 2 reveals
that prostate volume as well as the frequency
of positive surgical margins decreases as a
function of duration of neoadjuvant therapy. This should
be a lesson to those urologists who recommend a single month
or as few as three
months of neoadjuvant therapy before radical
prostatectomy. In my opinion, one to three
months of therapy is inadequate if maximal
prostatic tumor shrinkage is the purpose of
neoadjuvant therapy. The use of neoadjuvant
therapy for women with breast cancer shows that maximum regression
of the primary tumor
before surgery portends for a better overall survival,
and I believe that the same paradigm
holds true for patients with prostate cancer.
The return of measurable
levels of PSA in the blood to values greater then 0.3 ng/ml after
surgical removal of the prostate gland (radical
prostatectomy) almost always means that the
disease has returned and the treatment has
failed. This is termed PSA failure. The frequency
of PSA failure after radical prostatectomy
preceded by neoadjuvant therapy was compared
to PSA failure after radical prostatectomy
alone; the results are displayed in Table 3.
As is evident in
Table 3, six of seven clinical studies administered some form of preoperative
androgen ablation for only three months while
Baret et al continued therapy for six months
before patients were subjected to radical prostatectomy.
Each
study had a control group that was immediately sent to radical prostatectomy.
Though neoadjuvant treatment decreased the
percentage of patients with a positive surgical
margin, there has not yet been a definitive
reduction in the rate of PSA failure or overall
survival when compared to the control or
placebo treated groups. Why?
Figure 3 presents data obtained from
patients undergoing adjuvant chemotherapy
for breast cancer with the antiestrogen drug,
tamoxifen. The data from the Early Breast
Cancer Trialists’ Collaborative Group suggests
that five years of antiestrogen therapy is more
effective than two years of therapy in preventing
the recurrence of breast cancer. The fact
that there was no significant difference in cancer
recurrence between the treated and untreated
groups until more than two years of therapy
is of great importance, and has monumental
implications for patients with prostate cancer.
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Figure 3: Women
with breast cancer
treated with adjuvant tamoxifen (an
antiestrogen) benefited maximally if
therapy was continued for five years. |
Since both prostate
and breast cancer are responsive to antihormone drugs, we should
take the lead from successful studies already
completed for breast cancer and deduce that a
similar duration (2-5 years) of treatment
for prostate cancer patients may be necessary
to demonstrate increased survival.
The National Surgical Adjuvant
Breast and Bowel Project (NSABP) Protocol B-14, evaluated
five years versus 10 years of adjuvant tamoxifen
for early stage breast cancer and their data
indicated no advantage for continuation of
tamoxifen beyond five years.
Adjuvant Therapy Following
Prostatectomy
Horst Zincke is a leading urologist at the Mayo
clinic in Rochester, MN and he has carefully
analyzed pre- and post-PSA era Mayo Clinic
studies of prostate cancer patients undergoing
radical prostatectomy and lymphadenectomy
(removal of lymph nodes). Studying
patients with disease that had progressed to
involve lymph nodes, he compared the survival
rates of those who were treated with immediate
hormonal blockade to those receiving hormonal
blockade only after disease progression. He
found statistically significantly improved survival
for those undergoing immediate androgen
withdrawal as shown in Table 4. His initial
report demonstrated that patients whose
tumors had a normal complement of nuclear
DNA (diploid tumors) benefited the most from
early androgen withdrawal.
In still another study of early hormonal
withdrawal in patients with locally advanced
disease, Wirth and coworkers found
that patients immediately treated with the antiandrogen
flutamide (250 mg twice daily) given
after they underwent radical prostatectomy had
one-third the recurrence rate of those not
receiving such therapy. Subsequently, the Eastern Cooperative
Oncology Group (ECOG) under the leadership of Edward Messing randomized
98 men with prostate cancer that had spread to pelvic lymph
nodes at the time of surgery. These men
received immediate antiandrogen therapy
(with either goserelin,
an LHRH agonist, or orchiectomy), or were followed until disease
progression. There was a dramatic increase
in survival for only those patients treated
with early androgen withdrawal, as shown
in Figures 4, 5, and 6.
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Figure 4: Prostate Cancer-Specific Survival of Patients with Lymph Node Metastases
Treated with Immediate vs. Delayed Androgen Withdrawal Therapy (see Messing et al).
Survival is enhanced for patients treated with immediate androgen withdrawal.
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Figure 5: Progression-free Survival
of Patients with Lymph Node Metastases
Treated with Immediate vs. Delayed Androgen Withdrawal Therapy
(see Messing et al). Progression-free survival is enhanced for patients treated with
immediate androgen withdrawal.
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Figure
6: Overall Survival of
Patients with Lymph Node Metastases Treated with Immediate vs. Delayed Androgen Withdrawal Therapy
(see Messing et al). Overall survival is enhanced
for patients treated with immediate androgen withdrawal.
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Androgen Deprivation as
Adjuvant Therapy for
Radiation Treated Patients
Early Orchiectomy Plus Radiation
A second leading definitive treatment for localized
prostate cancer is some form of radiation.
Thus a Swedish study undertaken by Hans
Modig compared the combination of orchiectomy
and radiotherapy to external beam radiotherapy
alone as treatment for prostate cancer
confined to the pelvis. The clinical characteristics
of the patients in Modig’s study are summarized
in Table 5.
In his study, Modig concluded that progression-
free, disease-specific and overall survival
rates for patients with prostate cancer
and pelvic lymph node involvement are significantly
better after combined androgen
ablation and radiotherapy than after radiotherapy
alone (Figure 7). His results strongly
suggested that early androgen deprivation is better
than deferred treatment for patients with positive
lymph nodes. These findings are similar to
those reported by Horst Zincke and Edward Messing
for their surgically treated patients.
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Figure 7: Kaplan-Meier graph of disease
specific survival rate. Time axis is in years from start
of radiotherapy. Censored are living patients and those
who died of causes other than prostate cancer.
RT, radiation monotherapy.
A + RT, combined
orchiectomy and radiation.
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Figure
8: Kaplan-Meier Estimates of Overall Survival by Treatment Group.
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Figure
9: Kaplan-Meier Estimates of the Biochemically Defined Disease-free Survival.
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Early LHRH Agonist Plus
Radiation
A landmark study of the use of adjuvant androgen
withdrawal in patients treated with radiation
was undertaken by the European Organization
for the Research and Treatment of Cancer
(EORTC) by Professor Bolla.Bolla’s
study compared both (1) external radiation alone
and (2) external radiation combined with the
LHRH agonist, goserelin, to investigate the
added value of long-term androgen suppression
in locally advanced prostate cancer.
The five-year clinical disease-free
survival was dramatically different for both groups: 40% in the
radiotherapy-alone group,
and 74%
in the combined treatment group as shown in Figure 9 (above).
The five-year
overall survival was
62% and 78% respectively as shown in Figure 8 (above), and the
five-year
disease-specific survival
was 79% and 94% (no Figure provided). This study demonstrated
that for patients
with locally advanced disease, prolonged (three years) combined
androgen withdrawal
and radiation is superior to radiation alone.
RTOG Studies (see
Table 6)
Other clinical studies have addressed the role of androgen suppression
as adjuvant
therapy to external beam irradiation. The Radiation Therapy Oncology
Group reported
on three such randomized studies.
The first, Protocol 86-10, compared androgen deprivation plus
radiotherapy with
radiotherapy alone; androgen deprivation was found to significantly
increase the five year
rate of local control and to decrease the frequency of tumor
spread to distant sites.
Protocol 85-31, the second study, investigated
adding adjuvant androgen suppression
with goserelin (1) in patients classified as clinical stage T1–2
(tumor confined to the prostate gland) but with regional lymph-node
involvement, and (2) in patients with disease that had
penetrated the prostate capsule as noted after prostatectomy. There
was a statistically significant increase in the rates of local
control and freedom from distant
metastases, as well as disease-free survival, in patients
with centrally reviewed tumors with a Gleason score of
8–10. There was also a difference in predicted five year
survival in favor of the adjuvant-goserelin
group.
In the third study, Protocol 92-02, spearheaded
by Gerald Hanks’ patients assigned long-term
androgen suppression (28 months; starting two
months before XRT) with goserelin. When compared
to placebo-treated patients, this protocol resulted in
significantly better disease-free survival and local control,
time to distant metastasis, and time to
biochemical failure. Disease-specific survival
was slightly, but not significantly, higher.
All of the RTOG
studies demonstrate some form of benefit from the early addition
of androgen blockade to external beam
radiation. Gleason score, extent of disease
and duration of therapy are parameters
that impact on the extent patients benefited
from combined therapy (Table 6).
Adjuvant Hormonal Therapy
for Brachytherapy (Seeds)
Nelson Stone from Mt. Sinai Hospital in
Manhattan, NY studied 296 patients with localized
and locally advanced prostate cancer who
were candidates for prostate brachytherapy
(seed implant). As shown in Figure 10, his
group treated 181 patients with brachytherapy
alone, while 115 received complete androgen
blockade for three months prior to, and three
months after implantation. He found that at
the end of two years, repeat prostate biopsies
were one fourth as likely to be positive in the
hormone treated group.
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Figure 10: Hormone
withdrawal in conjunction with prostate brachytherapy was studied
by Stone and colleagues. |
Note
Thus far, studies of radiation or surgery in combination
with androgen deprivation in patients with
locally or regionally advanced prostate cancer have
been criticized because all trials failed to include a
control group treated with hormone treatment
alone. A current National Cancer Institute of Canada
trial is addressing the role of hormone treatment
alone, comparing maximum androgen blockade
with maximum androgen blockade plus pelvic
irradiation in stages T3–4 (disease through the
capsule or involving surrounding structures) node
negative patients. A prospective randomized study
by RTOG is also addressing this issue in a trial of
adjuvant therapy for high-risk prostate cancer
patients. In my opinion, based on the literature
reviewed above, this study will show that
patients benefit from early testosterone withdrawal
if it is continued for at least two years.
Androgen Deprivation
as Sole Therapy
Displayed in Table 7 is a comparison of patient
characteristics from three different studies. Bolla
and Messing, as you will recall, studied adjuvant
androgen withdrawal for radiated and
surgical patients respectively, while Jackson
Fowler studied continuous androgen
withdrawal alone as therapy for patients with locally
advanced disease. As is illustrated in Table 7,
Fowler’s patients were just as advanced, if not
more so, than patients enrolled in the Bolla
and Messing studies. I have indicated the five year,
disease-specific survival obtained in
Fowler’s hormonal ablation treated patients by
superimposing this survival point over both the
Bolla and Messing survival curves (Figures 11
and 12 respectively).
Figure 11 indicates the reported five-year,
disease-specific survival point of Bolla’s irradiated
and hormone ablated patients as 94%,
while Fowler’s androgen withdrawal alone group reported
a 92% five-year, disease-specific survival. In other
words, there is essentially no difference between the two groups
at five years. Figure
12 illustrates superimposition of Fowler’s five-year, disease-specific
survival of 92% over the Messing
(radical prostatectomy plus androgen withdrawal treated) disease-specific
survival curve. As shown, the survival
points at five years of follow-up are essentially identical.
Figure 13 illustrates Fowler’s cause or disease specific
survival curve taken from his publication. Are you surprised?
Does this mean that for patients
with locally advanced prostate cancer androgen deprivation therapy
alone is as good as radiation
or surgery plus androgen deprivation? As you should know, prostate
cancer is a slow-growing malignancy that may take 15 years or
longer to
cause death. The data are intriguing but are simply
not mature enough to suggest equivalence of
androgen ablation alone.
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Figure 11: Comparison of Fowler’s Conclusions
with Data from Bolla et al.
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Figure 12: Comparison of Fowler’s Conclusions with
Data from Messing et al.
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Figure 13: Fowler et al’s Disease-Specific Survival Curve.
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So there you have it. It looks to me
as though early hormonal blockade as adjuvant to other
definitive therapies (surgery or radiation) slows
disease progression and may extend life for many
years. The laboratory rodent studies of Isaacs, the
large World Health Organization clinical study
and the Veterans Administration studies, and the
Bolla, Messing, Zincke, and Hanks studies were the
first to suggest that early hormonal ablation could
be of value. I believe, based on the earlier breast
cancer work with tamoxifen and the Hanks and
Bolla studies, that the duration of androgen withdrawal
is very important. Based on current
knowledge, I would recommend when using
testosterone withdrawal as an adjuvant that
a minimum of two and a maximum of five
years of therapy be used for maximum benefit. Use for
longer periods may be necessary for patients with advanced metastatic
disease.
So what’s the big deal? Why the controversy?
Some in the urological community will go to
their graves believing early hormonal blockade
is of no value. They have written books and editorials
in journals condemning the practice.
They ignore results from newer studies and try to
find fault. There is no hope for them.
Others objectively face
the other side of the coin with their patients, which is the tradeoff
of
androgen withdrawal toxicity and the effects of such
on quality of life versus true
benefit. Testosterone lowering
comes at a cost to the
patient; the price is higher
for some than others.
Younger patients pay
more. They miss testosterone
much more than
older patients who frequently
start out with lower
blood levels and have been
losing testosterone since
their thirties and forties. Is the potential
increase in survival worth the toll?
For some, yes, and for
some, no. In my practice, some patients who would clearly benefit
from early androgen withdrawal decline the treatment. Androgen
withdrawal issues of loss of libido,
decreased muscle strength, depression,
and weight gain, osteoporosis,
breast enlargement, hot flashes and decreased
energy must be weighed against the potential
of increased survival. New drugs and treatment
protocols are addressing these toxicity
issues. For instance, high-dose Casodex® (150
mg/d) may preserve libido for many; bisphosphonate drugs
(Fosamax®, Actonel®, Aredia®, Zometa®) with calcium and vitamin
D protect
against bone loss; vigorous exercise may preserve
muscle strength and prevent weight gain; and
small doses of progesterone minimize
hot flashes. New drugs such as aromatase inhibitors
and tamoxifen may prevent breast enlargement.
If you have read
this far I congratulate you for enduring a complex and possibly boring
literature review. However, now you have been
exposed to the same clinical studies as your
urologist and you can talk the talk and walk
the walk with him. I hope you are now armed
with enough information to sit down with your
physicians and choose what is best for you.
References
1. Isaacs, J. T: The timing of androgen ablation therapy and/or chemotherapy
in the treatment
of prostatic cancer. The Prostate 5:1-17, 1984.
2. The Veterans’ Administration Cooperative Urological Research
Group studies of carcinoma
of the prostate: a review. Cancer Chemotherapy Rep Jan-Feb, 1975, 59
(1) pp 225–7.
3. Labrie F, Dupont A, Cusan L, et al.: Downstaging of localized prostate
cancer by neoadjuvant
therapy with flutamide and Lupron: the first controlled and randomized
trial. Clin Invest
Med 1993, 16:499–509.
4. Dalkin BL, Ahmann FR, Nagle R, et al.: Randomized study of neoadjuvant
testicular
androgen ablation therapy before radical prostatectomy in men with
clinically localized
prostate cancer. J Urol 1996, 155:1357–1360.
5. Goldenberg LS, Klotz LH, Srigley J, et al.: Randomized, prospective
controlled study comparing
radical prostatectomy alone and neoadjuvant androgen withdrawal in
the treatment
of localized prostate cancer. J Urol 1996, 156:873–877.
6. Soloway MS, Sharifi R, Wajsman Z, et.: Randomized, prospective study
comparing radical
prostatectomy alone versus radical prostatectomy preceded by androgen
blockade in clinical
stage B2 (T2BNxM0) prostate cancer. J Uronl 1995, 153:254A.
7. Hugosson J, Abrahamsson PA, Ahlgren G, et al.: The risk of malignancy
in the surgical
margin at radical prostatectomy reduced almost three fold in patients
given neoadjuvant hormonal treatment. Eur Urol 1994, 9:413–419.
8. Gleave, ME, Goldenberg SL, Chin, JL, et al.: Randomized comparative
study of 3 versus 8-
month neoadjuvant hormonal therapy before radical prostatectomy. The
Canadian Uro-Oncology Group.
9. Labrie, F, Cusan L, Gomez JL, et at.: Down-staging of early stage
prostate cancer: the first
randomized trial of neoadjuvant combination therapy with flutamide
and a luteinizing hormone-
releasing hormone agonist. Urology, 44:29, 1995.
10. Soloway MS, Sharifi R, Wajsman Z, et at.: Randomized prospective
study comparing radical
prostatectomy alone versus radical prostatectomy preceded by androgen
blockade in clinical
stage B2 (T2bNxM0) prostate cancer: the Lupron Depot Neoadjuvant Prostate
Cancer
Study Group. J Urol, 154:424, 1995.
11. Goldenberg SL, Klotz LH, Jewett MAS, et al.: Randomized, prospective,
controlled study
comparing radical prostatectomy alone and neoadjuvant androgen withdrawal
in the treatment
of localized prostate cancer. J Urol, 156:873, 1996.
12. Macfarlane MT, Abi-Aad A, Stein A, et al.: Neoadjuvant hormonal
deprivation in patients
with locally advanced prostate cancer. J Urol, 150:132, 1993.
13. Witjes WP, Schulman CC and Debruyne FM: Preliminary results of
a prospective randomized
study comparing radical prostatectomy versus radical prostatectomy
associated with
neoadjuvant hormonal combination therapy in T2-3 N0 M0 prostatic carcinoma.
Urology,
suppl., 49:65, 1997.
14. Aus G, Abrahamsson PA, Ahlgren G, et al.: Hormonal treatment before
radical prostatectomy:
a 3-year follow up. J. Urol., 159:2013, 1998
15. Homma Y: Neoadjuvant androgen deprivation precedent to radical
prostatectomy–its role
in short-term and long-term outcomes. Nippon Rinsho, 56:2162, 1998.
16. Klotz LH, Goldenberg SL, Jewett M, et al.: CUOG randomized trial
of neoadjuvant androgen
ablation before radical prostatectomy: 36 month post-treatment PSA
results. Urology,
53:757, 1999.
17. Wildschultz T, Louis L, Hourriez L and Schulman CC: Neoadjuvant
hormonal treatment
prior to radical prostatectomy: follow-up of a prospective randomized
study. Eur. Urol.,
30:210, 1996.
18. Soloway M, Sharifi R, Wajsman Z, McLeod D, Wood D, Jr., Puras-Baez
A and the Lupron
Depot Neoadjuvant Study Group. Radical prostatectomy alone vs radical
prostatectomy preceded
by androgen blockade in cT2b prostate cancer–24 month results.
J. Urol., part 2,
157:160, abstract 619, 1997.
19. Baert LV, Goethuys HJ, de Ridder DJ, et al.: Neoadjuvant treatment
before radical prostatectomy
decreases the number of positive margins in cT2–T3 but has no
impact on PSA progression
or survival in cT2–T3. J. Urol., part 2, 159:61, abstract 229,
1998.
20. Early Breast Cancer Trialists’ Collaborative Group: Systemic
treatment of early breast cancer
by hormonal, cytotoxic, or immune therapy: 133 randomized trials involving
31,000
recurrences and 24,000 deaths among 75,000 women. Lancet 339: pp 71-
85 1992
21. Seay, Thomas M.; Blute; Michael L,. Zincke, Horst: Long-term outcome
in patients with
pTxN+ adenocarcinoma of the prostate treated with radical prostatectomy
and early androgen
blockade. The Journal of Urology; 159:357-364, 1998.
22. Zincke, Horst, Lau,Weber, Bergstralh Erik et al: Role of early
adjuvant hormonal therapy
after radical prostatectomy for early prostate cancer. The Journal
of Urology® Vol. 166, pp
2208–2215, 2001
23. Wirth M, Frohmuller H, Marz F, et al. Randomized multi-center trial
on adjuvant flutamide
therapy in locally advanced prostate cancer after radical surgery:
Interim analysis of
treatment effect and prognostic factors [abstract]. Br J Urol; 80:263,
1997
24. Messing, Edward M. M.D., Manola, Judith M.S., Sarosd , Michael
M.D.,et al: immediate
hormonal therapy compared with observation after radical prostatectomy
and pelvic lymphadenectomy
in men with node-positive prostate cancer Nejm V 341 pp 1781-88, 1999
25. Granfors; Torvald, Modig; Hans, Damber; Jan-Erik et al: A prospective
randomized study.
The Journal of Urology; 159:2030-2034, 1998.
26. Bolla M, Gonzalez D, Warde P, et al: Improved survival in patients
with locally advanced
prostate cancer treated with radiotherapy and goserelin. N Engl J Med.;
337:295-300, 1997.
27. Bolla M, Collette L, Blank L, et al: Long-term results with immediate
androgen suppression
and external irradiation in patients with locally advanced prostate
cancer (an EORTC
study): a phase III randomised trial. Lancet; 360:103-108, 2002.
28. Pilepich MV, Winter K, Roach M, et al. Phase III Radiation Therapy
Oncology Group
(RTOG) trial 86-10 of androgen deprivation before and during radiotherapy
in locally
advanced carcinoma of the prostate. Proc Am Soc Clin Oncol; 17: 308a,
1998.
29. Pilepich MV, Caplan R, Byhardt RW, et al: Phase III trial of androgen
suppression using
goserilin in unfavorable prognosis carcinoma of the prostate treated
with definitive radiotherapy:
Report of Radiation Therapy Oncology Group Protocol 85-31. J Clin Oncol;
15:
1013–21, 1997.
30. Hanks GE, Lu J, Matchay M, et al. RTOG protocol 92-02:. A phase
III trial of the use of
long term androgen suppression following neoadjuvant hormonal cytoreduction
and radiotherapy
in locally advanced carcinoma of the prostate. Proc Am Soc Clin Oncol;
19: 327a
(abstr 1284), 2000.
31. Stone NN, and Stock RG: Prostate brachytherapy: treatment strategies.
J Urol 162(2):421-
6, Aug;1999.
32. Stone NN, Stock RG, Kao J, Unger P. Prostate biopsy results following
brachytherapy: factors
affecting a positive outcome. J Urol. 2000;163:1274a
33. Fowler, Jackson E. Jr., Bigler, Steven A, Kolski, John M et al:
Early results of a prospective
study of hormone therapy for patients with locally advanced prostate
carcinoma. Cancer Volume
82 pp 1112-1117, March 15, 1998.
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