Brian Moran, MD, expertise in geo-malignancy, specifically prostate and skin cancer, Medical Director, Chicago Prostate Center, talks about a new isotope to use in brachytherapy treatment for patients with prostate cancer.
Interview conducted by Ivanhoe Broadcast News in October 2017.
I want to talk about radiation treatment for prostate cancer. Tell me a little bit about first of all how this works. Brachytherapy what is it and how does it work?
Dr. Moran: Well brachy is a Greek prefix for a short; meaning short distance. Where tellie is the prefix for a long distance. And with radiation which is very effective in eradicating cancers there’s two forms. One is using external sources delivered into the body to the target volume or the tumor. Whereas brachytherapy is actually direct deposition of a radioactive material within the organ or tumor itself. And really the benefit there is that by putting a source of radiation right into the prostate, into the heart of the tumor as Alexander Graham Bell described in 1906, you’re able to deliver a much higher dose of radiation. We have shown that higher doses of radiation result in better cure rates. So this is an advantage of brachytherapy that really it’s limitless as to how much radiation you can put into the prostate. Whereas with an external source, you’re limited truly by the surrounding bladder and rectum, which only allows a certain amount of radiation to pass through.
What are the benefits to the patient with brachytherapy?
Dr. Moran: Well I think brachytherapy offers many benefits the first of which is it has an excellent track record. Its outcomes are equal to all other treatments and probably superior to most. And the reason again is because the amount of radiation or the biologically equivalent dose that we can place into the tumor is higher than any form of external radiation. But equally important I think quality of life issues are very good in properly selected patients. I believe that the convenience factor is exceptional. We see many patients that you know have to be on the job, cannot go in for daily treatment for many weeks of therapy. So brachytherapy is a onetime procedure. And this is appealing to a working man especially.
For which patients is this?
Dr. Moran: Well it’s not uncommon that we see patients who you know say, doctor I can’t have surgery I can’t afford to be out of work for four to six weeks or whatever the surgeons recommend. Or I cannot possibly go into a center for nine weeks Monday through Friday. And these are usually you know people working on the job that really have to be there every day if they want to keep their job. We’re seeing more and more of that every day so that subset is attracted basically just because of their work environment. But there’s many reasons people come for brachytherapy. Some just like the idea of it you know a onetime treatment. Others really understand the science behind it and really understand the data of how promising some of the recent studies are.
For whom is this not maybe the best idea, which patients would not do well with brachytherapy?
Dr. Moran: Well I always teach the residents never try to sell an implant to anybody you know. If a patient is fearful of a foreign body being put into his prostate, the last thing you want to do is an implant on him because he may regret that. From patient selection criteria; patients who have very large prostates or prostates that may cause them urinary difficulties we like to avoid those patients. Really across the spectrum of low, to intermediate, to high risk patients I think brachytherapy has a place. For low risk patients we can do just an implant or monotherapy and as we get into the more advanced cancers we usually combine the implant with a form of external beam radiation to treat the surrounding lymph nodes.
I wanted to talk specifically about the Cesium 131, can you tell me a little bit about that?
Dr. Moran: Yeah we’ve had an extensive experience with Cesium 131. It is a isotope that has a short half life as compared to the other ones which are iodine and palladium. The half life of Cesium is just over nine days and it also has a very generous energy compared to the other two isotopes. We’ve done a randomized study which we recently completed that really showed that Cesium was every bit as effective as I-125 and I think it’s an isotope that has a place. Some patients come in and say, you know doctor I can’t be radioactive for six months or it’s usually five half lives. So with Cesium there’s some element of radiation present for a month. Some people are fearful of the radiation and you know say I’d like the shortest isotope. But I think it’s really a decision that I make based on what I’m trying to accomplish with the coverage of the prostate.
When you’re talking about a half life and being radioactive can you explain again one of the side effects of having the implants?
Dr. Moran: Yeah, the half-life of an isotope is the amount of time in which half of the radiation will have decayed. So for an implant on day one you’re at a hundred percent of the total dose or a hundred percent of the total activity of the implant. And the half life for cesium would be nine point five days. And so at nine point five days the amount of radiation is down to fifty percent. And then another nine point five days it’s down to twenty five percent. And this continues and as a rule five half lives is when we really think the majority of the radiation is gone.
I wanted to back up a little bit and ask when you’re talking about brachytherapy and these implants one of the considerations, one of the side effects a person is radioactive are they not? Essentially they can’t be around other people?
Dr. Moran: By definition after a low dose rate prostate seed implant that individual is radioactive. But it doesn’t meet significance. Meaning is that person a threat to the public and the answer is no. We exercise rules that called ALARA, as low as reasonably achievable. So we give the patients recommendations, such as the amount of time a child could sit on their lap. We also look at the patient, if it’s a gentleman with a very generous abdomen he’s not going to have as much radiation in his skin surface as somebody who is very thin, because of the shielding affect of that body tissue. But for all practical purposes we’ve never had an occurrence that was due to a radiation you know, danger or whatever you call it because there just aren’t any with LDR implants.
What’s the benefit to having that half life, the lower if you would half life?
Dr. Moran: Well I think that it probably is a convenience factor for the patients that are really concerned about being around children. All too often we have questions about you know like, my daughter is pregnant she’s going to have a baby when can grandpa hold the baby? So a lot of those are patient driven, they just want the shortest half life.
I want to talk about quality of life for patients. Does that seem to be again the biggest reason why this becomes a stronger option for them or a more desirable option?
Dr. Moran: To a prostate seed implant? I think so. We’re seeing more and more of the baby boomer population. Their emphasis is more on quality of life issues. In fact I saw a gentleman today he’s fifty two years old he says, look I want to cure this cancer but I want to enjoy the rest of my life. Meaning I don’t want to be wearing a diaper or I don’t want to suffer from erectile dysfunction. And in general do your best to get rid of my cancer but leave my quality of life untouched. Aside from a temporary period where patients are experiencing increased urinary frequency, maybe rarely urinary retention with seed implants, they really do well; they really do not experience dramatic side effects especially to the bowels. With implants I can’t remember the last time I saw a patient who was symptomatic from radiation using a seed implant to the bowels.
Once the seeds are implanted they don’t come back out right?
Dr. Moran: No it’s permanent, that’s why the term permanent low dose rate seed implant. Those seeds are staying in place.
And they don’t biodegrade they will always be there?
Dr. Moran: They’re titanium shell is the seed and so that stays in place.
Is there anything I didn’t ask you about treating with brachytherapy and specifically the Cesium 131 that you would want people to know?
Dr. Moran: I know what I know because I’ve been doing this so long, doing it for close to thirty years and you know my observations are really from my practice how well these patients do. So when my patients come back in to follow up they’re constantly educating me. And you know the common response I get from patients is, doctor why would I do anything else. You know if I’m a candidate for seeds why would you do anything else? And that’s the truth of it. If a patient is properly selected and meets all of our criteria I think there’s no question implant is the best option because the cure rates are as good as anything else out there. And again if properly selected the quality of life issues are so much better. And this is well documented in the literature.
Is this an option for advanced cancer or …?
Dr. Moran: Oh no definitely. I think recent data has just been shown that in these locally advanced tumors we are never going to cure as high a percent with just radiation alone. And that’s because we are limited by the amount of radiation we can give. When we get into these bulky tumors there’s no question that the use of hormone therapy, external beam radiation to treat the primary tumor and the pelvic lymph nodes followed by a seed implant as a boost therapy delivers the highest biologically effective dose, the BED. By doing that I’m amazed at how well we’re doing with that set of patients, the big T3 patients, the bulky ones.
Stage one cancer, stage two cancer good with this?
Dr. Moran: Stage one and two cancers are limited to the prostate. Stage three there is evidence of extension beyond the prostate. Either out of the side wall of the prostate or into seminal vesicle then a T4 lesion would be one that’s literally invaded the bladder or the rectum.
So best for alone just brachytherapy for stage one?
Dr. Moran: Stage one and two if they’re low risk patients or favorable intermediate risk patients would be monotherapy. When we get into the more advanced intermediate risk patients with higher tumor grades or the real bulky T3 lesions those patients should be treated with trimodality therapy, endogen blockade followed by external beam followed by implant.
You had mentioned that you had done a study here on the isotopes, I just want to clarify that, was that on the Cesium 131?
Dr. Moran: We did a study randomizing patients for monotherapy using either Cesium vs Iodine 125.
And what did you find?
Dr. Moran: We found equivalent outcomes with the Cesium arm; they did just as well as the Iodine arm.
Again the benefit is to the patient, someone who is concerned about that dose of radiation around a pregnant loved one or a child?
Dr. Moran: Right. I also think that because of that energy sometimes I will use Cesium preferentially just to give a more homogeneous coverage. It’s hard to say but it does have a more generous energy that when combined with all the other seeds there may be less likely to be hot spots or cold spots. I haven’t proved it but that’s kind of what I believe.
Again anything I didn’t ask you that you want to make sure that people know?
Dr. Moran: Yeah I think if you really look at the true cost of say surgery followed possibly by external radiation, or a full course of external radiation whether its proton or linear accelerator based treatment compared to a low dose rate seed implant there’s no comparison. It’s approximately a third or less the total cost of these other treatment options. And when you look at cost and a treatment that has at least equal outcomes if not better that means the value is the greatest because you’re getting all of this for not as much money. And we hate to talk about money but sooner or later we have to talk about it. So there’s no question overall brachytherapy is the highest value treatment for prostate cancer, period.
Covered by insurance, is that cost passed onto the patients?
Dr. Moran: No, I think most insurance companies today truly recognize the value of brachytherapy.
And again we were talking about cost?
Dr. Moran: Yeah, I think with insurance companies and what things cost today in medicine and this concept of bundled payments, meaning that for a certain diagnosis insurance companies or the government might say this is what we will give the patient to receive the treatment. That immediately puts the patient as a consumer. He or she has to make the best decision, find the treatment with the most value for their malady or their illness and when it comes to prostate cancer brachytherapy, LDR brachytherapy will dominate.
About how many patients do you do brachytherapy on a year and of those about how many of Cesium 131?
Dr. Moran: I haven’t been doing a lot of Cesium in the past couple of years, more recently I have.
A little bit more lately with the Cesium?
Dr. Moran: I’ve been using more Cesium lately.
In a year how many implants have you performed in a year?
Dr. Moran: We’ve done over close to seven hundred Cesium implants I’d say.
END OF INTERVIEW
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