Brachytherapy or “internal radiotherapy” is a type of radiation therapy that involves placing radioactive material in the prostate gland. In a procedure called Low-Dose Rate (LDR) brachytherapy the radioactive seeds remain permanently and deliver a balanced dose of radiation to the prostate over a 6-month period. High-Dose Rate (HDR) brachytherapy delivers radiation through catheters that are temporarily inserted into the prostate. In both cases, it allows the use of high dose of radiation while reducing the risk of damage to nearby healthy tissues and increasing the likelihood the cancer is destroyed.
If you would like to watch a helpful video about the Brachytherapy procedure including preparation and what to expect after treatment on the Princess Margaret website, please click here.
Mapping the Prostate for LDR Brachytherapy
Men having an implant must undergo a mapping of the prostate to allow the brachytherapy team to work out all the technical details of the implant. This has to be done 2-3 weeks prior to the planned date of the implant. A transrectal ultrasound is used to generate images of the prostate that are entered into a planning computer. A plan is generated by the physicist and approved by the radiation oncologist. Seeds cannot be ordered until the plan is completed.
The Implant Procedure
The brachytherapy procedure is performed under general anaesthetic (you are not awake). The treatment is a day surgery, and takes approximately 1.5 hours to do. You will be required to take medicine (Flomax) 1 week before to optimize your urinary function and you will probably continue to take this medication for 3-6 months after the procedure. There will be a bowel preparation 2 days prior to procedure to make sure your bowels are empty at the time of procedure.
A small ultrasound probe is placed in the rectum and a picture of the prostate is generated. This imaging, in conjunction with a pre-established plan, guides the placement of the brachytherapy seeds. Approximately 100 seeds, each about the size of a grain of rice, are inserted into the prostate.
Immediately following your treatment session, you will feel some tenderness and bruising. You should be feeling better within a few days and able to return to work and resume normal activities.
One Month Check Up
Approximately a month after your treatment you may be required to return to the hospital to ensure that the brachytherapy seeds are optimally placed to deliver a balanced dose of radiation to the prostate. Your doctor will have you take x-rays of pelvis to verify the position and number of seeds, a chest X-ray to rule out seed migration to lung and CT scan and MRI scan to evaluate the quality of implant dosimetry.
It takes approximately 6 months for the brachytherapy seeds to deliver the full dose of radiation. You will have check ups at 3-6 monthly intervals in the first year, 6-monthly intervals through years 2-5 and then annually.
Regular PSA Tests
You will be monitored with PSA tests on a regular basis. A steadily declining PSA is a good indicator that the treatment has been successful in killing the cancerous cells.
Common side effects with brachytherapy include:
Other potential side effects include:
Not all patients have a cancer that is suitable for this brachytherapy. Currently, we are offering LDR brachytherapy to those patients who have:
Patients have presented excellent results, with a documented success rate of 90-95% 10 years after their treatment. A short course of hormone therapy may be used for men with prostate volumes ranging from 50 to 70 cc, making brachytherapy technically feasible.
HDR brachytherapy is a procedure that delivers a high dose of radiation to the prostate in a single or few fractions. The patient setup is similar to LDR brachytherapy; however, instead of permanent radioactive seeds, catheters are temporarily inserted in the prostate.
HDR brachytherapy is predominately used to provide an extra dose of radiation in addition to the external radiation (External Beam Radiotherapy - EBRT). It offers an effective method for delivering a high dose of radiation that conforms to the shape of the prostate while sparing radiation exposure to surrounding tissues. When combined with EBRT has the advantage of reducing the overall treatment duration as compared to EBRT alone.
In specific cases, the use of brachytherapy can also be an alternative to treat tumors that recur after local treatments including EBRT.
At Princess Margaret, HDR brachytherapy for prostate cancer is routinely offered under different clinical trials. Studies using magnetic resonance images (MRI) to guide brachytherapy are being successfully performed at PMH. As one of the world's leading providers of innovative research, PMH offers several clinical trials in prostate cancer. Our team will be glad to assist you and discuss all the available options.