My name is Dr. Sean Collins, I'm a radiation oncologist at Georgetown and I
use the CyberKnife to treat patients with brain tumors and other tumors of the
pancreas, prostate, and lung. We can treat both malignant and benign
brain tumors. The advantage of the CyberKnife is that
we can give high doses of radiation to individual lesions and spare the normal brain.
I've been fortunate that I've been around for the last 10 years and I've seen the
changes that have happened in radiation oncology due to the CyberKnife.
What's basically happened is that our treatments with the CyberKnife have gotten
more accurate so that we're hitting the tumor with sparing adjacent normal tissues.
Also because it's more accurate we can do the treatments more quickly so instead of
treating someone for weeks at a time we can get treatments done in one to two weeks.
This is actually extremely important to patients who have busy lives,
they're active, they're living their lives.
Not burning them by making them come for multiple weeks of treatment that are
unnecessary has really I think improved their quality of life.
Every day the fact that we have higher precision and accuracy there are new
things that we can treat with radiation that we couldn't do in the past.
I have actually the best job in the world - every day I get to use amazing
technology and treat people who had no options in the past.
CyberKnife treatment is a team sport. It requires a radiation oncologist,
a surgeon, a physicist, it requires a therapist, and we've had the CyberKnife
for 10 years. We're probably one of the most
experienced centers in the world with the CyberKnife.
We all work together, we're familiar with each other, and I think we had optimal
outcomes because of this level of experience.
Which brain tumors can be treated with the CyberKnife at Georgetown University
Hospital? We can treat both malignant and benign
brain tumors. Malignant brain tumors are generally
treated with either whole brain radiation or radiosurgery with the CyberKnife.
When we treat the whole brain there are more side effects to treatment because
we're treating the whole brain so we get fatigue, we get hair loss, and we can
actually get long term memory problems. The advantage of the CyberKnife is that
we can give high doses of radiation to individual lesions and spare the normal brain.
There is minimal fatigue, there is minimal hair loss, and there are minimal
memory problems. That's really important when you're
treating benign tumors. We also treat acoustic neuromas
and meningiomas which are benign lesions of the brain and we use CT scans to guide our
treatments so we only treat the tumor and not the normal brain.
Acoustic neuromas and meningiomas are generally treated when patients are not
candidates for surgery so if you're not a candidate for surgery because the surgery
would be too morbid or cause too many complications or if you're too old for
surgery we generally do radio-surgical treatment. How is the CyberKnife different from other
types of radiation and radio-surgery options? Other radio-surgery options for brain
tumors require a head frame bolted to the head - not only is this inconvenient
and it's uncomfortable for the patient but more importantly it makes us do the
planning and the treatment in one day. With the CyberKnife we use a face mask
that you can see through and you can breathe through and it's very comfortable
for patients. It also allows us to do the treatment
planning and the treatment when it's convenient for the patient versus doing it
in a rush. The advantage of this is that we can
actually do the treatments at a planned time and we can actually do it over
several days so instead of doing one treatment quickly we can do several
treatments over a week or two. The advantage of this is that this allows
us to do fractionation. So why is fractionation important?
Well if you give one treatment quickly to a large brain tumor it can cause things
like edema and headaches. When you fractionate the treatment you're
less likely to cause edema and headaches. Also if you have a tumor like
a meningiomas or an acoustic neuroma that are adjacent to critical nerves you're
less likely to injure the critical nerves adjacent to the tumor.
For example with an acoustic neuroma the goal is to preserve hearing.
We're more likely to be able to preserve hearing if we fractionate versus not fractionating.
So the general rule is that if you don't use a head frame bolted to the head you
can do the treatments when you want to do them and to me there's no rush to treating
people and I think when you're not rushing you do a better job.
What is involved in getting a CyberKnife treatment at Georgetown University
Hospital? First of all you meet with the radiation
oncologist and a surgeon and we sit down and discuss your case together and decide
whether you're a candidate for the treatment. If you are a candidate for the treatment
and you wish to go ahead with the treatment we would basically get a CT scan
or a scan of your brain then you go home and I sit down with the surgeon and we
decide what areas to target with radiation and what areas to spare.
You come back about a week later and you get five treatments - usually it's like
Monday through Friday for about an hour each - you lay flat on the table,
you don't feel it - radiation's invisible - you don't feel it, you don't smell it.
After an hour you get off the table and you're like "Hey doc, did you turn the
machine on?"
You can have mild headache and mild fatigue for about a week after the
treatment but the headache is actually rare and the fatigue is very mild and then
we just follow you with scans every certain number of months after and is very
easy and convenient for the patients. Why does Georgetown give several
treatments with CyberKnife instead of just one treatment?
The reason why we give several treatments is because we want to decrease the
symptoms from treatment like headaches and fatigue. Let's say you had a large brain
metastasis and we were going to give you one large dose of radiation you would
likely get a headache after that treatment. That's because the tumor will swell
and cause the normal brain tissue injury. What we do is we give the treatments over
several days and your body can handle small doses of radiation at each
individual time and have less toxicity, have less swelling.
Another example of this is when we treat meningiomas or acoustic neuromas.
Acoustic neuroma patients are at risk of losing their hearing and we know that
hearing loss is a terrible symptom of the treatment. By giving several treatments over a week
instead of one large treatment we believe that we can preserve hearing better in
patients and we know how important that is to patients.
why does the approach of several treatments make sense when treating
meningiomas and acoustic neuromas?
Your meningiomas and acoustic neuromas are near critical structures in your brain.
One of the critical structures next to your acoustic neuroma is the seventh nerve
and that controls your ability to hear. If you injure that nerve you don't hear
anymore so fractionation, giving a little radiation over five days, decreases the
risk of injuring that nerve. Why should I come to Georgetown for my
CyberKnife treatment?
CyberKnife treatment is a team sport, it requires a radiation oncologist,
a surgeon, a physicist, it requires a therapist, and we've had the CyberKnife
for 10 years. We're probably one of the most
experienced centers in the world with the CyberKnife.
We all work together, we're familiar with each other, and I think we hit optimal
outcomes because of this level of experience.
What progress do you have to report in treating prostate cancer with CyberKnife?
We've been treating prostate cancer with the CyberKnife for about five years.
We're about to treat our 500th patient at Georgetown.
We are actually the busiest prostate cancer center in the world for CyberKnife treatment.
What we've learned is that the acute toxicity of prostate CyberKnife treatment
is minimal, it's a convenient treatment, it's only five treatments over two weeks,
it's very easy for patients, most patients work full time.
The PSA drops after treatments have been excellent.
On average your PSA will drop to 1 at one year after treatment.
The other thing is that other investigators have been looking at the
treatment too now and five-year data has recently been published and the PSA
responses from the treatment are as good or better than conventional radiation
treatments for prostate cancer. What can I expect if I'm having CyberKnife
for prostate cancer?
If you're undergoing prostate CyberKnife treatment basically what you do first
is you have to meet with Dr. Lynch and myself to discuss the treatment.
If we think that you're a candidate for the treatment Dr. Lynch will put gold
markers in your prostate and the reason why we put gold markers in your prostate
is because we want to actually track where your prostate is.
Your prostate actually moves and if we don't track motion we're going to miss it
so the gold markers we put in your prostate and we actually track where your
prostate is so we can give high doses of radiation accurately.
The next thing we do is we get an MRI of your prostate because if we're going to
radiate your prostate we actually want to know where it is so MRI imaging is the
best imaging modality to see the prostate and we use that to guide your CyberKnife treatment.
You come back about a week later and you get five treatments over two weeks.
We usually do it like Monday, Wednesday, Friday the first week and Tuesday,
Thursday the second week. You lay on your back for an hour and the
machine does all the work, you don't feel anything, radiation's invisible, you don't
see it, you don't smell it. At the end of the first treatment you're
like "Hey did you turn the machine on?" Around the fourth or fifth treatment you
can get some urinary frequency and urgency, some bowel frequency and urgency
- these are the same symptoms that you see with conventional radiation - it's mild,
it lasts for about a week, and by one month after treatment you're back to normal.
Who is a good candidate for CyberKnife treatment for prostate cancer?
All prostate cancer patients are candidates for prostate CyberKnife treatment.
In general people with low PSAs and low Gleason Scores or low risk disease we
generally treat with five large doses of radiation with the CyberKnife.
Patients who have higher PSAs and higher Gleason Scores are at higher risk for
having disease outside the prostate and we generally treat them with three large
doses of radiation with the CyberKnife and five weeks of conventional radiation to
treat a larger area around the prostate.
But everybody who has prostate cancer is potentially a candidate for CyberKnife treatment.
In the decade that Georgetown University Hospital has been treating people with
CyberKnife, how have you seen your patient's quality of life change for the better?
I've been fortunate that I've been around for the last 10 years and I've seen the
changes that have happened in radiation oncology due to the CyberKnife.
What's basically happened is that our treatments with the CyberKnife have gotten
more accurate so that we're hitting the tumor with sparing adjacent normal tissues.
Also because it's more accurate we can do the treatments more quickly so instead of
treating someone for weeks at a time we can get treatments done in one to two weeks.
This is actually extremely important to patients who have busy lives,
they're active, they're living their lives.
Not burning them by making them come for multiple weeks of treatment that are
unnecessary has really I think improved their quality of life.
In lung cancer treatments the paradigm has completely shifted from doing six
weeks of radiation to doing a few large doses of radiation.
Most of these patients are sick, they don't want to be coming back and forth to
the hospital every day. They prefer to be living their lives
and being at home with their family than being in a hospital setting so I think it's had
a great impact on quality of life. How has the convenience of CyberKnife
increased the number of patients who are now receiving treatment for their cancer?
A lot of patients weren't getting treatment because they couldn't do it,
they couldn't logistically actually do it. With a few treatments it's much easier
for patients who live far away from a cancer center to get treatment.
If you live three hours from the closest radiation oncology department you can't go
for six weeks of radiation but you probably could go for three to five treatments.
A lot of patients who weren't getting treatment because they couldn't do it
logistically are now getting treatment.
If I have had traditional radiation treatment for my tumor can I still receive
CyberKnife treatment?
Ten years ago before we had the CyberKnife there would be patients that would come
into our department who had already received radiation previously and had
failed radiation treatment and they had no options, they could do nothing.
Because the CyberKnife is actually so precise and so accurate we can actually
give radiation to areas that have been previously radiated in a safe
and effective manner.
To see a patient who thought they had no options and now they at least have an
option, it's unbelievable how that changes their world view.