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Lymph
Nodes & Surgery
May 1, 2007
Many surgeons won’t do a radical prostatectomy when they
find there’s cancer in a man’s lymph nodes. They
assume that surgery isn’t a viable choice because there’s
no longer a chance that the operation can remove all of the prostate
cancer. Radiation therapists have similar concerns. There was
a period of time when I also agreed with this viewpoint. But
a number of studies have changed my opinion.
In 1994, Zagars, et al. from MD Anderson Cancer Center published
treatment results for a group of men with cancerous lymph nodes
but no detectable cancer in their bone. The men received hormonal
therapy rather than surgery or radiation. After ten years, most
of the men had failed hormonal therapy. Investigators then took
the important step of finding out where in the body hormone-resistance
first appeared. In more than half the cases, hormone resistance
appeared first in the prostate gland. In somewhat more than 40%
of the cases, hormone resistance appeared in the bone and in
less than 5% of cases in the lymph nodes. The implications of
this study are very provocative: even after lymph node metastases
developed, the cancer remaining in the prostate gland is still
the biggest threat to the patient’s continued health.
So then what happens if we operate on men with lymph node involvement?
The largest series of patients treated in this fashion are those
from the Mayo Clinic under the care of Dr. Zincke. For more than
20 years, Dr. Zincke has treated such men with radical prostatectomy
followed by hormonal therapy. And over the years, he’s
written many papers detailing his results. Overall, his patients
do extremely well. Since he treated a large number of patients,
he can provide a great deal of detail on how the lymph node involvement
affects his results. At one extreme, men with only one node have
a 95% chance of being in remission at ten years. As the number
of abnormal nodes and amount of cancer increases, the chance
of being in remission drops to almost 50%. Other factors also
alter success rates. If the cancer has a normal number of chromosomes
(diploid), hormone resistance is quite uncommon regardless of
the extent of lymph node spread. A cancer with an abnormal number
of chromosomes (aneuploid) tends to do much worse.
One randomized controlled trial (published in 1999) tested Dr.
Zincke’s approach. In this study, surgeons operated on
all men with known lymph node metastases. Within three months
after surgery, half of the men started hormonal therapy with
Zoladex alone. After a median of seven years, close to 80% of
men on combined treatment were in remission compared with 18%
of those who’d only had surgery. And less than 10% of those
on combined treatment died compared with more than 30% of those
treated with surgery alone. This trial has been criticized because
it was terminated early for the difficulty researchers had getting
the ideal number of patients into the trial. I think this criticism
misses the point: the differences were astoundingly positive
for combined treatment and are consistent with the MD Anderson
paper we mentioned in Vol 8 # 12. It represents a dramatic confirmation
of Dr. Zincke’s claims. Furthermore, these results are
consistent with laboratory studies of prostate cancer in animal
models and make sense in terms of what we know about prostate
cancer biology.
So, at this point, I think there’s a strong case for using
radical prostatectomy to treat men with lymph node—but
not bone—metastases if you follow surgery with adjuvant
hormonal therapy. Of course, controversy remains about the best
way to administer hormonal therapy. In particular, it may well
be that intermittent hormonal therapy will prove to be both more
effective at cancer control and less toxic to the patient.
To read more about Managing Lymph Node Metastases, click
here to purchase Volume 9 Issue 1. |
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