HDR Brachytherapy
An I.V. will be set up to administer medication to induce drowsiness. Next, a series of plastic needles (catheters) will be placed into the prostate. All the catheters will be connected to the brachytherapy machine that sends radiation directly to the tumor site. Vital signs will be taken by a nurse throughout the course of treatment to see how your body is responding to the therapy. During the 10 – 15 minute treatment time, the patient will hear the clicking and whirring sound of the drive mechanism as it advances and withdraws the radioactive Iridium-192 wire through each catheter. The patient will receive two15-minute radiation treatments. This outpatient process is typically repeated a week later. Between these treatments you will have a four to six hour interval that is spent in outpatient recovery. The patient is only radioactive while connected to the brachytherapy machine. There is no continuing radioactive exposure in the hospital room or at home.

Possible Side Effects
The most common side effects are fatigue or skin irritation, depending on the area of the body being treated. Your brachytherapy team will help you minimize them and even prevent them from occurring.

Is High Dose Rate (HDR) Prostate Brachytherapy Ready for Prime Time?
By Bradley R. Prestidge, M.D.

Though the vast majority of prostate brachytherapy performed in the U.S. is with permanently placed sources (“seeds”) as I have been doing for nearly 14 years, another technique of prostate brachytherapy called High Dose Rate (HDR) has been gradually gaining interest. This form of prostate brachytherapy has not been studied for as long as the permanent approach, but some centers are now showing impressive results at 10 years of follow-up.

The technique of HDR involves the temporary placement of a series of small, hollow catheters into the prostate through the perineal skin (just like a seed implant). Approximately 2 hours later, after some very sophisticated computer modeling and manipulation by the physics staff, the catheters are then connected to an HDR unit which sends a single radioactive source (Ir-192) down each catheter in turn for very brief periods (seconds) to give the full treatment in a total of less than 15 minutes. This treatment is typically repeated 1-2 times per implant. Each patient undergoes this sequence once or twice, depending on the protocol.

This approach has some potential advantages over permanent seed placement. The main one is the ability to shape and mold the dose being delivered to the prostate and away from the bladder, rectum, and urethra before the treatment and after the catheters are placed. If the model does not show a satisfactory dose distribution, the dwell positions and dwell times of the single source are altered until the desired result is obtained. With seeds, once the seed is placed, we can’t take it back and the dose is delivered accordingly.

I have been involved in permanent prostate seed implantation for my entire career because I have seen and continue to see excellent results and limited complications compared to other forms of treatment. However, seeds do have some limitations that may be better addressed by HDR:
 
1. Gland size- we do not usually try to implant glands larger than 60 cc because of difficulty reaching the entire gland with the needles. In HDR, there is no such limitation because the dose distribution can be manipulated to account for gland size.

2. Bladder dysfunction- Patients tend to have less urinary irritative symptoms following HDR than seeds. This may be useful among patients who already have poor bladder function to begin with.

3. Shorter duration of side effects- since the radiation is given in a matter of minutes instead of months, side effects may be expected to be less prolonged.

4. Higher doses outside the gland- for those patients with a higher risk of extracapsular extension of disease, HDR dose can be pushed out well beyond the borders of the gland.

But HDR does have limitations, not the least of which is that all HDR patients must also receive external beam radiation. With the exception of a few centers in the country studying HDR as monotherapy (without external beam) on an investigational trial basis, HDR has always been given in combination with external beam- there just isn’t enough experience with HDR alone as of yet. Perhaps there will be for selected patients when some of these trials begin to mature in the next 5-10 years.

I have been following HDR with interest for many years. I performed large numbers of HDR-type prostate implants during my years in the Air Force and published on the technique, but abandoned HDR for seeds since there was more worldwide experience with them. But now that the HDR data is maturing and looks to be comparable to seeds at 10 years, I have decided to resume HDR in selected patients.

In my opinion, these selected patients include those with intermediate or high-risk cancers (not those who are very well treated by seeds alone), or with large gland size or significant bladder dysfunction. This allows us at TPI to offer the full gamut of state of the art, non-surgical treatment options for patients with prostate cancer ranging from 3D conformal radiation to IMRT, to seeds, to HDR, and combinations thereof.

We have recently performed several HDR cases which went very well, with minimal patient discomfort and excellent dosimetric quality implants. The patients have all been quite pleased. And we have found it to be true that it is much easier to perform a high quality implant with HDR than seeds, because the computer can make up for any imperfections in placement. However, because of our extensive seed experience, the difference in our dosimetric quality between the techniques appears to be insignificant. This would not likely be true at the vast majority of other community or university based seed implant programs where the experience is more limited.