Sean Collins, M.D., Ph.D., a radiation oncologist at Georgetown University
Hospital in Washington, D.C.
Who is a candidate for this procedure?
Dr. Collins: A good candidate for the CyberKnife is someone who has clinically
localized prostate cancer. That means prostate cancer that's confined to the
prostate gland, and it's somebody who has low to intermediate risk features, so
people with Gleason scores of seven and less, with a PSA of 20 or less.
What's the traditional treatment for prostate cancer?
Dr. Collins: Actually, we still treat people the traditional way. It's eight weeks of
daily radiation, five days a week, Monday through Friday, and there are some
symptoms associated with it. It's eight weeks, so men aren't happy with it. They'd
rather be on the golf course than spending 8 weeks with their doctor getting
treated for prostate cancer.
Is that the difference the CyberKnife makes?
Dr. Collins: The good thing about the CyberKnife is it's only five treatments, and
you're done. Usually we do them in one week or one or two weeks. It's actually
only 5 treatments instead of 40 treatments. It's very convenient for patients. A lot
of patients live far away from a radiation/oncology center, so imagine you live two
or three hours from a major medical center. How would you get treated for your
prostate cancer? You almost have to move to closer to the center to get treated.
So the CyberKnife is very convenient for men who don't have a major medical
center near them.
How long does the treatment take?
Dr. Collins: It takes about an hour each day, so you have to lay flat on the table.
We try to make you comfortable. The machine actually rotates around the
patients and gives radiation to the prostate from hundreds of different directions,
which makes the treatment very conformal.
How does the treatment work?
Dr. Collins: First, we put gold fiducials, or little gold seeds, in the prostate so our
machine can actually move with the prostate and track it. What that lets us do is
it makes us have tighter margins in the prostate and we can get the radiation in
How long does each treatment take?
Dr. Collins: There are five treatments. Each treatment takes about one hour.
What do you like about this option?
Dr. Collins: I like it because it's very convenient for men. It has side effects
similar or less than the other radiation options for men with prostate cancer.
What are they?
Dr. Collins: Side effects with prostate cancer treatment with radiation are --
urinary frequency, bowel frequency are the early side effects. Delayed side
effects are you can have rectal bleeding about a year after, and you can have
decreased erections about two or three years after.
Can this be used apart from surgery?
Dr. Collins: This is without surgery. The only surgical part of this procedure is
putting four gold seeds, or fiducials, within your prostate. It takes the urologist
about 5 minutes to do that, and it's actually less burdensome than a biopsy.
Is surgery much more risky than this treatment?
Dr. Collins: With surgery, incontinence can happen. I think if you want surgery,
you should be treated by an experienced surgeon, but it still can happen if you're
unlucky. Incontinence is rare with any type of radiation.
Who wouldn't be eligible for CyberKnife treatment?
Dr. Collins: I would skip this with people who have disease outside their
prostate, in their lymph nodes or in their bone. There are some patients who
have pacemakers or defibrillators that don't allow us to get an MRI for treatment
planning, and an MRI is a very sophisticated type of imaging that allows us to
see the prostate anatomy very well. If someone is going to give high doses of
radiation to my prostate, I want them to know exactly where the prostate is. If
you're not a candidate for an MRI, you're not a candidate for CyberKnife. Also,
there are certain things that make tracking the prostate difficult, things like hip
replacements. They're made out of metal. We're actually tracking metal fiducials,
so that makes it more difficult to treat those patients.
What happens if the radiation misses the correct area?
Dr. Collins: It could do damage to the rectum and the bladder. I call the pelvis
the high rent district. There are lots of important things in the pelvis, and if you're
missing the prostate, you're giving your rectum high doses of radiation, which
could cause rectal bleeding. If you're missing the prostate, you're giving high
doses of radiation to the bladder, which could cause bleeding from your bladder.
I like to prevent those problems if I can. So with the CyberKnife, we try to prevent
What's the success rate compared to traditional radiation?
Dr. Collins: It should be better than traditional radiation, because what we found
over the last 20 years is that if you give radiation faster to prostate cancer,
patients do better in terms of their cancer outcomes. So it should theoretically
actually be better. We've been using it for about four years. The preliminary data
is coming out, and the PSA drops more quickly with the CyberKnife than it does
with conventional radiation. Prostate cancer is a cancer of 10 or 20 years, so we
won't know how good the results are for that long, but we're not willing to wait
because we have the best radiation technology in the world, and I'm not willing to
wait 20 years to give this opportunity to men.
Is prostate cancer one of the most treatable cancers?
Dr. Collins: It's very treatable if we find it early. Every man over 50 should be
getting a PSA and a digital rectal exam every year so that we can find the cancer
early. It's much more curable if we find it early.
END OF INTERVIEW
This information is intended for additional research purposes only. It is not to be used as a prescription or advice from Ivanhoe
Broadcast News, Inc. or any medical professional interviewed. Ivanhoe Broadcast News, Inc. assumes no responsibility for the
depth or accuracy of physician statements. Procedures or medicines apply to different people and medical factors; always consult
your physician on medical matters.
If you would like more information, please contact:
Sean Collins, MD, PhD
Georgetown University Hospital