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HIGH DOSE RADIATION (HDR) IMPLANTS FOR PROSTATE CANCER
AT JOE ARRINGTON CANCER TREATMENT CENTER (JACC)

- Introduction
- HDR compared to Permanent Seed Low Dose Rate (LDR) Implant and External Radiation
Therapy (XRT)
- HDR Procedure
- Side Effects and Complications
- Follow-up
- HDR Team
- References

Introduction :
Management options for localized prostate cancer include, observation with serial measurement of PSA, hormonal blockade, radical prostatectomy, nerve sparing radical prostatectomy, cryosurgery, External Beam Radiation Therapy (XRT), Intensity Modulated Radiation Therapy (IMRT), Proton Beam Radiation Therapy, Permanent Seed Low Dose Radiation (LDR) Implants, and HDR Implants. The National Institute of Health (NIH) Consensus Panel concluded in 1988 that 10 year survival was comparable with either radiation or surgery [1]. The American Urological Association convened a Prostate Cancer Clinical Guidelines Panel in 1995, and reached similar conclusions [2]. For a more detailed discussion of all treatment options for localized prostate cancer, please see our article entitled Management of Localized Prostate Cancer on our website.
HDR (High Dose Rate) Radiation Implant has been in clinical use for the treatment of cervix cancer for nearly 40 years. HDR Implant Boost was added as a boost to XRT in the management of prostate cancer more than 15 years ago. HDR offers the most elegant radiation method currently devised of "painting" the radiation dose to the desired target, while minimizing dose to surrounding normal tissue. Survival results compare very favorably to radical prostatectomy, XRT, and Permanent Seed LDR [3-9]. Many publications using these other treatments exclude patients with advanced T-Stage, high PSAs, and higher Gleason Scores. Seattle has published that 78% of their HDR Implant patients have no evidence of recurrent cancer 10 years after treatment. There were no patient exclusions based on T-Stage, Gleason Score or PSA. These results rival the best that have been published with any other technique.

HDR Implant vs. Permanent Seed LDR Implant :
With respect to the two implant techniques, HDR offers some significant advantages over I-125, and other permanent seed (e.g. Pd-103) techniques :
1. HDR is a temporary seed placement technique. With the permanent seed I-125 or Pd-103 procedures, the patient is permanently implanted with ~ 100 seeds. Therefore, the patient goes home radioactive, with radiation exposure to family members and others. With HDR, the patient goes home with no radiation inside them.
2. With the permanent seed techniques, seeds can migrate in the prostate after implant, resulting in dose inhomogeneity. In addition, seeds can leak out of the prostate into the bladder, or into the bloodstream. Seeds have been known to embolize to the lung and heart. HDR is a closed system with a blind end needle, so the seed can not escape.
3. HDR allows much more flexibility in tailoring tight dose distributions to the bladder, rectum, and especially, the urethra. This has resulted in a much lower incidence of urinary retention, and urethral stricture with HDR, than with permanent seeds.
4. HDR can treat extraprostatic extension better than the permanent seed techniques.
5. Pubic arch interference and large prostate size (> 60 cm3) create such technical difficulties with Permanent Seed implants that these patients are excluded. HDR Implant can be done in these patients.
6. The permanent seed technique calls for a pre-plan, which is not always matched by the real implant. There may be areas of too many seeds (hot spots), and other areas of not enough seeds (cold spots). The problem of cold spots is one of the rationale used for adding supplemental XRT. These problems do not occur with HDR.

Standard management with HDR, has been HDR Implant x 1 + daily XRT x 5 weeks. However, there is no conclusive evidence that the added daily XRT improves outcome. Blasko et al, reviewed the results of 634 prostate cancer patients who underwent Permanent Seed Implant +/- XRT treated in Seattle [10]. There was no significant difference in PSA survival. Patients were subdivided into low risk, intermediate risk, and high risk, based on T-Stage, Gleason Score, and PSA. No survival difference was found in any patient subgroup. Notably, there was increased rectal morbidity in the patients undergoing Implant + XRT (8%) vs. Implant alone (2%). Blasko concluded, "Although the addition of XRT to brachytherapy is conceptually appealing for patients with higher risk prostate carcinoma, we were unable to demonstrate a benefit." Grado et al, also have reported no difference in PSA survival in a series of 490 patients treated with Implant, Implant + XRT, or Implant + Hormonal Blockade [11].
Therefore, a case can be made for HDR Implant alone. In that event, the patient would need two HDR Implants, spaced about 2-4 weeks apart. Several investigators have reported good early results with HDR alone [12]. In our experience of 300 patients, we also have observed no survival benefit to XRT + HDR vs. HDR alone. We have observed higher rectal complications when daily XRT is added. Therefore, JACC has an IRB Protocol for HDR alone. Please see the JACC website for the JACC-004 Protocol.

HDR Implant Procedure :
Before proceeding with HDR Implant, the patient is seen in consultation at JACC. All management options are discussed, with referenced outcome data for each option provided.
If the patient elects to proceed with HDR Implant, the process involves a bowel cleansing procedure, followed by sigmoidoscopy, placement of the implant device under local anesthesia, cystoscopy, CT Scan for 3-Dimensional Radiation Treatment Computer Planning, and three HDR treatments delivered over a 24 hour period. The bowel cleansing procedure involves starting a liquid diet the day before the procedure. The patient is then given laxatives and enemas. On the day of the procedure, an i.v. is started to aid in the local anesthesia. The procedure can also be done under spinal or general anesthesia, but these methods carry significantly more risk to the patient. With spinal anesthesia, there is a slight chance of damage to the spinal cord, and subsequent paralysis. With general anesthesia, there is a slight risk that the patient will not wake up. Local anesthesia is the safest method. Our Team has done more than 100 HDR Implants under local anesthesia, with no complications. Following placement of an i.v., in JACC, the patient is given low doses of Demerol and Versed. Then, a Foley Catheter is placed. Sigmoidoscopy is done to clear out residual stool from the bowel preparation the night before, and to rule out rectal lesions. The Ultrasound Probe is then placed, and measurements of the Prostate recorded. Local anesthetic is administered. The Implant needles are placed under direct Ultrasound guidance to encompass the entire Prostate and Seminal Vesicles. Cystoscopy is then done to assess the urethra and bladder. The entire procedure takes about 45 minutes. The patient is then sent for a CT Scan. The images are sent by fiberoptic link for 3-Dimensional Computer Radiation Treatment Planning. It is during this step that the radiation dose is "painted" on the prostate, taking care to avoid the urethra, bladder, and rectum. The Iridium HDR seed can spend as little or as much time as we direct in any given position along the needle pathway. This permits the most elegant tailoring of radiation dose delivery currently possible with any radiation technology.

Side Effects and Complications :
HDR Implant side effects have been reported to be significantly less than with XRT or Permanent Seed LDR Implants. Typically, patients experience some degree of urinary irritation including burning, frequency, and possibly some blood in the urine for several days to weeks. Urinary retention requiring re-insertion of a Foley catheter has been rare in our hands, occurring in < 1% of the HDR cases, compared to up to 30% with LDR. Chronic irritative urinary symptoms have also been uncommon, with urethral stricture occurring in < 2% of HDR patients, compared to 10-15% with LDR. Chronic rectal symptoms of urgency, rectal bleeding and pain, have been uncommon. Usually these symptoms are resolved with routine medications. Permanent rectal symptoms such as rectal ulceration, have occurred in < 1% of patients, compared to 10% with XRT. Sexual activity may be resumed immediately following HDR. The ejaculate may be brown, bloody, or watery. Sexual dysfunction after HDR is similar to Permanent Seed Implant and XRT, with at least 50% of patients experiencing Erectile Dysfunction (ED). ED can be treated with Vitamin E, Trental, Neurontin, and Viagra. HDR dose can be tailored off of the neurovascular bundles to minimize ED, but this is not recommended, since this is a potential site of tumor recurrence. Patients may return to work immediately following removal of the HDR Implant device. Fatigue can occur uncommonly following completion of HDR. When this occurs, it resolves within 1-2 weeks.

Follow-Up :
Patients should be seen 2 weeks after HDR Implant for evaluation of potential side effects and treatment as needed. Then, we recommend follow-up evaluation with PSA check every 3 months for the 1st year, every 6 months for the 2nd year, and then annually.

HDR Experience :
Our HDR Team includes nurses, radiation oncologists, urologists, physicists, and radiation therapy technologists. We have performed more than 300 HDR Prostate Implants, and more than 100 under local anesthesia. Overall, we have done more than 1,000 HDR Implants for tumors of the Cervix, Vagina, Vulva, Breast, Lung, Oral Cavity, Esophagus, Anal Canal, Rectum, and Prostate since 1995. We are affiliated with numerous National Clinical Research Groups, including the Radiation Therapy Oncology Group (RTOG), National Surgical Adjuvant Breast and Bowel Project (NSABP), Gynecology Oncology Group (GOG), and Southwestern Oncology Group (SWOG). We currently have numerous active clinical trials.

Management of localized prostate cancer is a complex subject. Treatment recommendations should be tailored to the patient's medical condition, life expectancy independent of the cancer, and aggressiveness of the cancer. Improvements in curative options, such as IMRT and HDR, continue to evolve. HDR compares very favorably to radical surgery and XRT, in regard to cure, morbidity, and quality of life. It appears that IMRT will as well. Patients should seek opinions from the different specialists involved in managing prostate cancer before arriving at a treatment decision. Prostate cancer is almost never a medical emergency, so that patients have time to reach a comfort zone before embarking on treatment.

References:
1. Journal of the National Cancer Institute Monographs, 1988 ; 7 : 3.
2. Urology, 1995 ; 154 : 2144
3. International Journal of Radiation Oncology, Biology and Physics, 2000 ; 48[3] : 149
4. Cancer Journal of Scientific American, 1997 ; 3 [6] : 346
5. Radiotherapy and Oncology, 1998 ; 48 [2] : 197
6. Radiotherapy and Oncology, 1997 ; 44 [3] : 237
7. International Journal of Radiation Oncology, Biology and Physics, 2000 ; 48[3] : 147
8. Journal of Endourology, 2000 ; 14 [4] : 351
9. Cancer Control, 2001 ; 8 [6] : 511
10. Radiother Oncol, 2000 ; 57 : 273.
11. International Journal of Radiation Oncology, Biology and Physics, 1998 ; 42 : 289.
12. Proceedings of the May, 2001 Annual American Brachytherapy Society Meeting.

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