Home: PCU
1|2003: Editor's note
 |
Editor’s Note |
|
| Evidence Base |
Every physician likes to remember the patient that defied the odds
and experienced an unexpectedly favorable outcome, but in the enclosed
program, Thomas Keane challenges us to consider cases where radical
prostatectomy failed to achieve tumor control. I was particularly
struck by the second patient, a man who entered the Early Prostate
Cancer adjuvant trial randomizing between two years of bicalutamide
150 mg and placebo. The patient experienced a biochemical relapse
one year after completing adjuvant therapy, and when the blinded
trial code was broken, it was revealed that the patient had received
bicalutamide. This man has now responded to maximal androgen blockage,
but my medical oncology background in breast cancer makes me wonder
if the relapse would have occurred if adjuvant therapy had been
utilized for a longer duration.
When tamoxifen was first utilized as post-operative adjuvant therapy
of breast cancer, the standard duration — following the model
of chemotherapy — was only one year. Women who relapsed following
treatment were routinely retreated with tamoxifen, and often the
tumors responded. Gradually, the duration of adjuvant therapy was
extended, and clinical trials randomizing between one and two years
of tamoxifen revealed a survival advantage for longer treatment
(Figure 1). Eventually, an optimal duration of five years was established
through randomized studies, but it took about a decade to determine
this.
I am generally very cautious about drawing analogies between breast
and prostate cancer, but often the similarities are undeniable.
It’s gratifying to encounter other physicians with interests
in both endocrine-related tumors, and this issue of Prostate Cancer
Update includes an interview with radiation oncologist, Frank Vicini,
who has done sentinel research in both fields.
One of the curiosities I find with prostate cancer is that the
approach to adjuvant androgen deprivation differs based on the primary
local treatment. Specifically, it appears that high-risk men treated
with primary radiation therapy are more likely to receive adjuvant
endocrine therapy than men at the same risk who are treated with
radical prostatectomy.
In breast cancer, adjuvant therapy is recommended based on the
risk of systemic relapse, whether the primary local therapy is lumpectomy/radiation
therapy or mastectomy. When I have asked prostate cancer research
leaders about this, most have commented that the adjuvant trials
conducted by the radiation oncology cooperative groups have demonstrated
benefit, but the post-surgical trials have been less convincing.
Dr Vicini, who is very familiar with the breast cancer literature,
had another perspective: specifically, that the surgical clinical
trials have utilized a shorter duration of adjuvant treatment and
thus resulted in less benefit.
In an emerging era of evidence-based medicine, we are often left
with lessthan- perfect evidence, which is where clinical judgment
becomes critical. Another of Dr Keane’s cases is a 52-year-old
man with a PSA of 12 and a Gleason 8 tumor with seminal vesicle
invasion on radical prostatectomy.
What interested me most about this case discussion was the very
active role the patient and his wife had in sorting through the
available clinical trial data with Dr Keane. These discussions resulted
in an individualized decision that encompassed the entire biopsychosocial
panorama of this man’s life.
Many of the key clinical decisions in cancer treatment must be
made based on clinical trial results that are not definitive. This
series is intended to provide the perspectives of research leaders
on the strategic integration of these data into discussions with
patients and, also, insights into how evolving research will address
these issues in the future. Dr Keane’s cases demonstrated
that many key issues require much more randomized trial data to
allow more evidence-based decisions.
— Neil Love, MD
|
