So let's go through some of these radiation treatments,
and I want to know according to Mack Roach what you like, don't like, who's a good candidate,
the way I need to perceive it if I'm excited about radiation because they're being inundated
by all these radiation types and commercials and you got to help set me straight. So, I thought I
would just walk through them alphabetically, even, because you still talk about brachytherapy, but
I say that not many people talk about it as much anymore and I want you to take me through it.
Well, okay, let's start with brachy because
the oldest form of radiation that was used to treat prostate cancer was actually brachytherapy
That's right
and brachytherapy comes in two flavors: there's the permanent, you stick it in there and leave it,
and there's a temporary where you connect it to the person, deliver the radiation,
and pull it out—it's called high dose rate brachytherapy, some call it HDR brachytherapy
versus the permanent implant which is sometimes called LDR low dose rate brachytherapy.
Now, people are frequently confused because they call they say, "high dose radiation" and
they're referring to "high dose rate." Actually, the high dose rate radiation is a lower dose
than the low dose rate radiation. The way to think of it is like if you go to buy a car
you can pay, say, $50,000 for the car now or you could finance it over seven years and pay $80,000.
Yeah.
So, the low dose rate radiation is like financing the radiation over a period of time and the high
dose rate temporary implant is like paying for the car in cash. They both work; they probably
work about the same. The lowest consistent PSAs I've ever seen is with low dose rate radiation
and the total dose is higher, the problem is those people had lower volume disease, so it's not clear
that this is an inherent biologic response or a reflection of the patient selection.
So, you mentioned that, so that's one misunderstanding. I think HDR is sold
as HDR because people think, "oh that might be more effective than LDR; the high dose might be
more effective than that old permanent seed, but how do you look at it when people want
you to say pros and cons and they had equal outcomes—the permanent versus the temporary,
or I and then the other side — the other thought I have is that where
to even find these people anymore who do these permanent brachytherapy and these procedures?
Well, you got a lot of questions don't you?
I know, I do, but because I want someone to make a brachytherapy commercial.
Okay, here's the simple thing. Okay, HDR has two major advantages.
One is, it's technically easier to do in the sense that you put the needles in,
replace the needles with catheters, and then you connect it to a computer and you can adjust
the doses where you are. It allows you — and the other major thing is from a technical standpoint,
the machine from which the radiation comes, that same machine can—that source—can be used to treat
other cancers. So, if you have cervical cancer, GYN cancer, head and neck cancer, use the same
radioactive source over again because it's inside of a catheter and it's still sterile. A permanent
implant, you have to carefully stick those seeds where you want to put them and wherever you land,
wherever they land, that's where they are and sometimes one gets outside the prostate,
will get into a vein or "ghost" and go to another part of the body; it can go to the heart;
it can go to the lung; most of the times, it's not any big deal to lose an occasional seed,
but it's a little bit disconcerting. I had a patient that I treated once—and I've
done more than 1500 permanent implants—one patient happened to have a geiger counter,
and he went and he called me up and said, Dr. Roach, how come I got a seed in my heart? Well, so
we started using stranded seeds, you know, you you can get them on a strand rather than free seeds
and that may reduce it somewhat; it may reduce it completely, depends on where you put them. There's
different philosophies about planting implants. There's some people that will consistently place
seeds well outside the prostate in order to make sure they have it covered and there are
other people that will try to squeeze them all in the gland; it technically is more challenging,
but anyway permanent implants, you can't use the sources over again because they're consumed. You
put them in the patient, you leave them there, so you got to keep getting shipments of radioactive
seeds. So, if you're in a developing country, if you're in Nairobi, and you want to start doing
brachytherapy, you want to use a machine that you can also use for treating cervical cancer
because there's a lot of cervical cancer in developing countries
than to buy seeds that you have to, you know, keep having radioactive seeds imported, and they also
because they're radioactive and they have a short half life. So, if your case gets delayed a week,
then you got to recalculate the plan. So the the the high dose rate, where the the source is so hot
that it that it takes a long time to decay, while the low dose rate whether,
you know, you got to have it down to the days how many days especially if you use
some of the ones with a shorter half-life. Some of these sources have a half-life of nine days.
You know, you say, "whoa," you know if the case gets delayed a week that's a real problem for you.
So, but they both work and that's brachytherapy. Pretty much,
the high dose rate also is a little bit more flexible in terms of the size of the prostate
because that way you can if you have a really big prostate, you don't have to worry so much
about the bone, you can put the catheter in, you can modify the dwell time to compensate for poor
geometry in terms of where the catheter is placed, while with a permanent implant
you get what you get and if the bone is in the way then that's a problem. Having said that, some of
the most pleased patients I ever treated got a permanent implant. One time, they had the seeds
put in, and they were cured, and some of them are very well known famous people, very happy people;
I would say that the happiest patients I ever treated had a permanent implant, and the most
unhappy patients I ever treated had a permanent implant, especially when we use brachytherapy in
the salvage setting. So, we actually sometimes the patient's been treated with external being
radiation and they have a recurrence, and I will go back and reimplant them and that's the kind
of thing that should not basically be done in the community. It's it's not done as frequently as it
should be done, but it should be done by people that have the physics support, the backup, and
the experience to do it, but salvage brachytherapy of external beam failures is a real useful tool.