Hi, I'm Dr. Scholz. Let's talk about prostate cancer.
In this video, we're going to cover focal therapy for prostate cancer. That means treating
a section of the prostate rather than the whole gland.
Many people aren't aware of the fact that standard treatments like radiation don't focus
on the tumor specifically, they focus on the borders of the prostate. Historically, we
haven't had the technology to find exactly where the cancer is located and so for safety
reasons and for thoroughness the gland is targeted rather than the tumor.
When we talk about focal therapy, we're talking about treating a section of the gland where
the tumor is located. The primary reason to consider focal therapy is to reduce side effects.
When the whole prostate is targeted with radiation or surgery, the incidence of impotence, urinary
incontinence, urinary bother, and rectal damage is substantial, even in the hands of the best
experts. The idea of doing a focal treatment to a section of the gland to reduce the risk
of side effects is a very attractive proposition.
When we're talking about focal therapy, we're talking about a lot of different ways to destroy
a section of the prostate. We could use radiation: seed implant radiation or beam radiation (which
is called either Cyberknife or SBRT), laser treatments, freezing the gland, high-intensity
focused ultrasound, radiofrequency ablation. There are a number of different ways that
doctors can treat a section of the gland.
In my view, as an expert in referring patients, the quality or the expertise of the doctor
doing the treatment is probably more important than the type of treatment being used. There
are certain advantages and disadvantages. For example, take cryotherapy. Cryotherapy
involves inserting a probe into the tumor area, circulating liquid argon creating an
expanding ice ball where the cancer is, circulating warm water to thaw that iceball, refreeze,
thaw on a second cycle, and remove the probe. But when you freeze a section of the body,
the body fights that and tries to compensate for that freezing, and there's a transition
zone that is not completely frozen. For that reason, cryotherapists have to freeze a larger
margin around the tumor to make sure that they kill the tumor. Laser treatments, on
the other hand, and this is not to speak as an advantage or disadvantage, has a very sharp
line of demarcation between the treated area and the untreated area, so they don't have
to treat as large an area, but there may be a greater risk of not getting all the tumor.
So all of these different methodologies require special skills and training and it's not clear
that any one is superior to the others, but as a general overall view the idea of just
treating a section of the prostate is very attractive and a number of centers are springing
up across the country and around the world to give this type of treatment.
So clearly, not all patients would be eligible for focal therapy. Patients that have bilateral
tumors, for example, would require such a large area of the prostate to be treated to
ensure a cure that there'd be little if any advantage for leaving a small rim of gland
so the type of patients that can undergo focal therapy are those that have the cancer limited
to one side of the gland.
The other critical component is for the tumor to be easily visualized with imaging, either
color doppler or multiparametric MRI. The doctors use an imaging tool to determine where
to treat. Some tumors which are detected by a random biopsy, for example, may be small
and even invisible on an imaging study. Such patients won't be good candidates for focal
therapy because the doctors can't see exactly where to treat.
So the two requirements to review, then, are imaging visibility on a scan, and unilaterality—that
is, tumor confined to one side of the gland.
What specifically are the drawbacks for focal therapy?
Well, it's new, and many of the doctors that are offering focal therapy are still in their
learning curves. They're still learning who to treat, how much to treat, and so without
good quality control, it's difficult to know where to go and who to trust. Some of the
treatments that we've talked about will be covered by insurance, but others are not so
cost can be an issue—sometimes tens of thousands of dollars—whereas if you went through a
standard IMRT or seed implant that would be covered 100% by your insurance. The third
problem with focal therapy: Because only a portion of the gland is treated, or in other
words a section of the gland is untreated, patients will have to be monitored for the
rest of their life for the possibility of a new cancer showing up in the untreated gland.
Patients who have focal therapy are going to need to be monitored with active surveillance
just like a patient who pursues active surveillance as a primary therapy. Lastly, the concern
about cure rates with focal therapy is that if the whole prostate is treated with a standard
radiation treatment, for example, how can those patients not have a higher cure rate
than someone who only has a section treated. I think there's some truth to those arguments,
but with modern imaging and using a generous margin of treatment area around the tumor,
cure rates with focal therapy are going to be very very high. Undoubtedly, the side effects
will also be fewer and as a result, I believe that focal therapy is going to be a growing
area, a very popular type of treatment in the future. The main problem, of course, being
that this is very new and people are still in their learning curves.
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