Brachytherapy for Prostate Cancer
What is brachytherapy?
Brachytherapy is one possible treatment for prostate cancer. Brachytherapy is a type of radiation therapy that is given inside the body. Radioactive material is put into the body, as close as possible to the cancer. The tissues surrounding the radioactive material receive the most radiation. As you get further away, the radiation received becomes less. This results in less damage to healthy tissues in the area of the cancer, compared to external beam radiation. Brachytherapy also delivers a higher dose of radiation in a shorter period of time, compared to external beam radiation.
What are the different types of brachytherapy for prostate cancer?
Brachytherapy is most often used for prostate cancer that is confined to the prostate gland or the area immediately around it. It may be used in combination with traditional (external beam) radiation when the cancer is more advanced.
Prostate cancer can be treated with low dose rate brachytherapy or high dose rate brachytherapy. Below we will review how each type is given and what you can expect during this treatment.
Low Dose Rate Procedure
Low dose rate (LDR) brachytherapy may also be called “seeds” or permanent brachytherapy. This procedure is done in the operating room with anesthesia to numb the groin area. Thin needles are inserted through the perineum skin (the area between the anus and the scrotum), into the prostate, using a small board to guide them. Small pellets (seeds) of radioactive material are inserted through the needles. The needles are then removed, leaving the seeds behind, spaced throughout the prostate. The seeds remain in the prostate permanently. The actual number of seeds depends on the size of the prostate, but is typically around 100. The seeds slowly release radiation into the surrounding tissue, over several months, killing cancer cells.
This procedure is typically done as an outpatient and you will go home after a short time in the recovery room. You will be radioactive after the procedure with LDR because the seeds remain in place. This radioactivity slowly decreases over time. Although the level of radiation is relatively low, it is recommended that small children avoid sitting on your lap and pregnant women stand at least 5 feet away for at least six months after the treatment. There is a small risk of the seeds becoming dislodged and moving somewhere else in the body (such as the lungs), or being excreted in semen or urine.
High Dose Rate Procedure
High dose rate brachytherapy may be called HDR or temporary brachytherapy. HDR is used less often than LDR in the treatment of prostate cancer. For this procedure, you are taken to the operating room and given anesthesia to numb the groin area. Needles are inserted through the perineum skin (the area between the anus and the scrotum), into the prostate, using a small board to guide them. An ultrasound probe is placed in the rectum to confirm the needles are placed correctly. Flexible catheters (tubes) are inserted through the needles. The needles are then removed and the tubes are left in place. (see picture below)
The tubes and a urinary catheter will remain in place during the entire treatment time, which usually lasts 2-3 days. The patient remains in the hospital during this time. Once the tubes are placed, a CT scan is done to verify the catheter placement and generate the treatment plan (how long the radioactive source will remain in place).
Once the treatment plan is finalized, the brachytherapy machine is connected to the catheters. The machine automatically pushes the radioactive pellets into each of the catheters, and removes them when the application is complete. The amount of time each pellet stays in a position is called the dwell time. This time is calculated to ensure an adequate dose is delivered to the prostate and that normal structures, like the urethra, receive as little radiation as possible.
To prevent exposure to others, no one is allowed in the treatment room while the pellets are out of the machine. You may have the pellets inserted several times over a 2-3 day stay in the hospital. After each application, the radioactive pellets are removed from your body and you are not radioactive.
You will be limited to strict bed rest while the catheters are in to prevent movement of the catheters. After the final treatment with the pellets, the catheters are removed. Possible side effects can include pain in the perineum and burning and hesitancy with urination due to the urinary catheter, which can last up to 2 weeks. Long-term side effects (months to years after treatment) may include burning with urination, incontinence of urine or stool, diarrhea, rectal bleeding, and impotence.
Choosing Your Treatment
Not all prostate cancers can be treated with brachytherapy. To decide which form of treatment is best for you, discuss all your options with your providers. No randomized clinical trials have found that one option (surgery, radiation, brachytherapy) is better than the others. It is important to talk about possible side effects from each treatment, as these can vary based on your age and health. Each treatment has different recovery times as well. These may help you decide which treatment is best for you.