By Satyendra Persaud MBBS DM (Urol) FCCS
Registrar, Department of Urology
San Fernando General Hospital,
Trinidad and Tobago
We have already noted that there are several ways in which we can treat prostate cancer confined to the prostate. One option which we discussed last time, was radical prostatectomy or removal of the prostate. Today, we will discuss radiation therapy.
How is radiation
therapy delivered?
Usually radiation is delivered in one of two ways:
External beam radiotherapy in which the beams are aimed at the prostate from outside the body
Brachytherapy in which radioactive seeds are implanted in the body and deliver a dose of radiation over time
How is external beam radiotherapy carried out?
Once your cancer is deemed to be localized to the prostate you may be a candidate for radiotherapy. Think of it as an X-ray except much more powerful. Your therapist will plan your radiotherapy, by determining the angles at which to aim the beam for maximum effect. Modern radiotherapy uses CT scanners to ensure that the radiation beam is focused on the prostate and not on adjacent organs. Radiotherapy will take several weeks and you will likely have to attend 5 days a week. While each session may only last a few minutes, setting up and ensuring that you are well positioned in the machine may take longer. Depending on the grade of cancer you may be required to undergo hormonal injections for up to 3 years following your radiation.
How is brachytherapy carried out?
If your cancer is confined to the prostate and is low to intermediate risk, you may be a candidate for brachytherapy. Men with problems urinating, more advanced cancers and large prostates are not good candidates. Tiny radioactive seeds, each resembling a rice grain, are surgically implanted into the prostate. Like EBRT, brachytherapy requires planning as we need to decide how many seeds we need and how we will place them. In the operating room, the urologist will use a rectal probe to look at the prostate while he uses needles to place the seeds strategically into the prostate. The procedure is done under anaesthesia. After the procedure you will likely need a urinary catheter for a brief period. Since the seeds give off radiation for several months, you may be asked to stay away from small children and pregnant women.
What are potential side effects of treatment?
While both of these entities are very effective treatment options for prostate cancer, there are several noteworthy complications. Although every effort is made to focus the radiation beam on the prostate during EBRT, there is a risk of damage to adjacent organs such as the bladder or rectum and may cause bleeding in the urine or stool – this can occur years following treatment. Damage to the rectum, called radiation proctitis rarely occurs with brachytherapy. There is also a risk of erectile dysfunction with EBRT as well as brachytherapy which increases with time. Rarely, you may develop an inability to hold up the urine, called incontinence or the urine passage may scar down, preventing the free flow of urine- this is called a stricture.
How will I be monitored after therapy?
Whether you had EBRT or brachytherapy, your urologist will monitor you PSA (blood test that we discussed earlier) following your procedure. We do not look at an absolute value but we look at the lowest level that your PSA achieves – this is called a nadir. If your PSA starts to rise significantly above the nadir, then you may require further treatment. It is not uncommon for the PSA to rise slightly around a year and a half following your radiotherapy – this called a “PSA bounce” and is usually temporary. Your urologist will determine whether a rise in your PSA signifies a PSA bounce or something more ominous.
As usual, I will be happy to answer any questions via email: satyendrapersaud@yahoo.com
