Radiation Therapy Side Effects for Prostate Cancer Patients

Patients often ask, “What are the side effects
of treatment for each of the individual treatment options?” Well, with surgery has two major side effects
beyond the risks of surgery—infection, bleeding, etc. The two major side effects of the procedure
are impotence and incontinence. Now for incontinence, that’s leakage of urine, any sort of leakage,
any sort of leakage is about a third of patients. And what I mean by that is people leaking
when they lift something heavy or playing tennis or when they laugh. So when you ask
large groups of patients in health services research studies, “Do you leak?” about a third
of them will say yes to that question. 2% or maybe a little bit less of patients will
have severe leakage requiring additional surgical intervention by the urologist or use of diaper
or clamps to prevent the leakage. Some of that is just the nature of the surgery. The
surgery is done in such a way where the prostate is taken out and then when it’s sewn back
together, when the edge of the urethra are sewn back together, it’s near where the sphincter,
the muscle that controls continence that stops the leakage, it’s just right near there, so
mechanically sometimes some patients will just leak which it just kind of comes part
and parcel with the surgery. Now, impotence also goes along with radical prostatectomy
and the number that tends to be reported is about a 50% rate of impotence. Now the impotence
from surgery is a nerve based impotence, in other words, there are nerves in the periphery
of the prostate which are associated with potency. Now, these nerves are not big nerves
that the surgeon can see. They’re small bundles of nerves that are anatomically in an area
where the surgeon, where the urologist, knows where they are and they attempt to spare those
nerves in the so-called nerve-sparing prostatectomy, but they’re not always able to do that. One
reason might be that the tumor is nearby. Another reason is that these areas are hard
to locate. So about 50% of patients may end up being impotent. So this nerve based impotence
is cutting the telephone wires, cutting the communication to allow for erections and potency. Now, with radiation, side effects are a little
different. Incontinence is not a primary complication or side effect of standard radiation treatments—certainly
not without a surgical intervention precipitating incontinence. However, rectal problems and
rectal damage are. Going back 15 years, rectal damage were 15 to 20% of patients. With the
advent of IMRT and that ability to shape dose and bring dose off the rectum and bring dose
off the bladder the risk of asymptomatic rectal bleeding (what we call a grade 2 complication)
runs between 2 and 4% depending on the study you read and symptomatic rectal bleeding requiring
the GI doctor to go in and zap a little bleeding blood vessel in the rectum—that risk is
about a half of a percent. So these are fairly low risk. the bladder problems that used to
be associated with external beam radiation 15 years ago, 15-20% risk in those days, have
fallen to less than 1% with these new IMRT techniques and some of the other techniques
that I’ve described to you. Now, we’re seeing the same risk of complications
with stereotactic body radiation, the SBRT. As I mentioned before in the permanent seed
implant the risk profile is a little different. They have a unique risk of causing urethritis,
irritation of the urethra or burning on urination, and they have an asymptomatic rectal bleed
rate of about 5 or 6%. More than the IMRT. The high dose rate interstitial implant has
a risk profile of complication very similar to the IMRT and the SBRT with very low rectal
and bladder complications. The mechanism by which radiation causes impotence
is a vascular based impotence. It turns out that the nerves are basically radiation resistant,
but the vasculature is not and what radiation does is it accelerates the aging process.
If, for example, you look at a group of 70-year-olds who are potent who receive radiation and then
look at them seven years after the radiation about half of them are impotent. It’s the
same 50% that is often reported with the radical prostatectomy except in that situation what
you got is 70-year-olds becoming 77-year-olds, and over that period of time some of those
folks will become impotent and in fact, that’s exactly what’s happening. The radiation is
accelerating the aging process. That being said, nowadays, there are vascular based treatments
for vascular based impotence, the kind of impotence that radiation causes. Drugs like
Levitra, Cialis, and Viagra. In randomized trials, the reversal of radiation-induced
impotence is about 80% with these medications. Other medical conditions can affect complications
such at as potency. Patients with diabetes or cardiovascular disease such as a history
of heart attacks or strokes or peripheral vascular disease have a much higher incidence
of impotence in general, and certainly a higher incidence of radiation impotence as well.
Smoking is also a predisposing factor towards impotence in general, certainly vascular disease,
and smokers have a much higher likelihood of becoming impotent after radiation therapy.

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