Who can receive
radioactive seed implant (brachytherapy)?
Prostate brachytherapy is the oldest radiation therapy technique for the
treatment of prostate cancer. When it was first used to treat prostate cancer,
preloaded radium needles were inserted into the prostate and left in the gland
for a period of time. Recent advances in prostate brachytherapy have made it
another "gold standard" for treating prostate cancer. Prostate seed
implant can be used alone for definitive therapy, or it can be used as a boost
treatment after external beam irradiation.
Interstitial brachytherapy has been employed for
patients with T1 and T2 tumors. Patients are selected for favorable
characteristics, including low Gleason score, low PSA level, and stage T1 to T2
tumors. Patients with more advanced disease may receive brachytherapy as the
boost treatment after external beam radiotherapy. Implant therapy alone is not
recommended for patients with high Gleason score, high PSA level, or stage T3 or
above. Information and further study are required to better define the effects
of modern interstitial brachytherapy on disease control and quality of life, and
to determine the contribution of favorable patient selection to outcomes.
There are two different types of radioactive seed
available currently, Iodine-125 and Palladium-103 seeds. Both implants release
low energy radiation over a short time period. Palladium gives off its energy in
approximately 3 months, and for Iodine implant, 6 months. There is no clinical
evidence that one implant is more effective than the other; however, Palladium
implants are used to treat more aggressive disease (i.e., higher Gleason Scores)
by some investigators.
One of the important advantages of radioactive seed implant is that it has less
side effects compare to external beam radiation or surgery. Long term side
effects such as impotence occur less frequently after brachytherapy. There is
generally no incontinence, diarrhea, or abdominal discomfort following seed
implantation. Rates of erectile dysfunction after radioactive seed implants
often correlate with the age of the patient. Impotence is rare for fully potent
patients younger than 60. For patients older than 70, radioactive seed implant
may cause impotence in about 30-50% of cases. This rate is still much lower than
For implant radiation therapy, a brief stay in the hospital may be needed when
the radioactive material is implanted. The implant may be temporary or
permanent. When a temporary implant is removed, there is no radioactivity in the
body. The amount of radiation in a permanent implant is not generally dangerous
to other people, but patients may be advised to avoid prolonged close contact
with others for a period of time.
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