Prostate seed therapy, a type of low dose rate (LDR) brachytherapy, is a form of internal radiation which involves placement of tiny radioactive seeds directly into the prostate gland to kill the cancer cells at close range. This type of therapy has been proven in early-stage prostate cancers to be equally if not more effective than prostatectomy (removal of the prostate gland) with very low complication rates. Prostate seed therapy may be offered alone or in combination with external beam radiation to treat prostate cancer.
The radiation from each of the tiny implanted seeds is slowly delivered to the targeted site and a small margin of surrounding tissue over several weeks to months. The radiation, which is emitted from the inside out, does not travel very far, so it is able to treat the cancer directly without damaging critical surrounding structures.
Prostate seeds are generally placed into the prostate with ultrasound guidance during a short outpatient procedure at the hospital. Up to 50-100 radioactive seeds are implanted permanently into the prostate gland. Each of these radioactive seeds is no bigger than a grain of rice.
Once the procedure is completed, a patient will be able to return to normal activities within a couple of days. The seeds will gradually lose their radioactivity over time. They may remain in place forever without causing the patient any harm.
Because the radioactive sources are placed directly into the prostate, it allows direct treatment of the tumor while minimizing the exposure of healthy surrounding tissues such as the bowel and the bladder. This reduces the number of side effects a patient may face. Mild-to-moderate short-term side effects may include increased urinary urgency or frequency, weak urine stream, discomfort during urination or sexual activity, or mild loose stools. In most cases these side effects begin to subside in the weeks following prostate seed placement. As well, medications may be available to help offset some of these side effects.