RADIOTHERAPY AND BRACHYTHERAPY

What is external beam radiotherapy (EBRT)?

External beam radiotherapy is where X-ray beams are focused through the prostate by an external machine. This is painless and takes only a few minutes. The dose is repeated 5 days a week for 7 weeks. Often you will be given hormone therapy for a period of time as this improves the long term results of treatment. 

What are fiducial markers?

Fiducial markers are small bullet shaped seeds that are implanted into your prostate before the EBRT treatment starts. This is done as a minor procedure through the rectum, similar to a prostate biopsy. They are visible on X-ray and help to aim the radiotherapy beams during your treatment sessions. They do not need to be removed afterwards.

What are the advantages of EBRT?

EBRT is ideal for patients with localised prostate cancer who need treatment, but are unsuitable for surgery due to lack of fitness or other medical problems that may make a long anaesthetic dangerous. It also avoids some of the complications of surgery such as infection or bleeding.

What are the side effects of EBRT?

Undergoing a 7 week course of radiotherapy is tiring and many patients experience fatigue after the first couple of weeks. There may also be some minor burning around the skin, this looks and feels just like sunburn.

While modern radiotherapy techniques are very accurate, it is impossible to not to irradiate surrounding areas such as the urethra, bladder and rectum.

• Urethral damage may lead to stricturing or blockage causing difficulty urinating
• Bladder damage (cystitis) may cause frequent voiding and discomfort
• Rectal damage (proctitis) may cause diarrhoea and rectal discomfort
• Damage to the erection nerves will lead to erectile dysfunction

As radiotherapy takes a long time to have an effect on healthy tissue, the side effects of radiation damage may appear years after your treatment. Erectile dysfunction following radiotherapy may take a year or two to develop. Severe delayed radiation injury to the bladder and rectum is rare, but is very difficult to treat if it occurs.

What are the disadvantages of EBRT?

While EBRT remains the best choice for some patients with localised prostate cancer, there are some disadvantages:

• The intense schedule is logistically difficult for some people, especially those travelling from country areas
• It is sometimes difficult to tell if all the cancer has been treated successfully
• If the cancer is not completely treated or recurs, surgery to remove the prostate is technically difficult and often leads to poor functional outcomes
• Severe, delayed radiation cystitis or proctitis is very difficult to manage

What is adjuvant EBRT?

Adjuvant EBRT is where a shorter course of radiotherapy is given soon after surgery for localised prostate cancer. This may be suggested when:

• The pathology report shows a positive margin, suggesting there may be a small amount of cancer remaining
• The pathology report shows a very aggressive cancer and we want to reduce the risk of a future recurrence

Adjuvant EBRT does cause some damage to the surgical site, which can lead to scarring of the join between the bladder and urethra causing a stricture or blockage. If you had a nerve sparing procedure, this will lead to poor results in terms of erectile function.

What is salvage EBRT?

Salvage EBRT is given after surgery if there is evidence of cancer recurrence in the pelvis over time. This may be demonstrated by a slowly rising PSA some time (often months to years) after your operation.

What is brachytherapy?

Brachytherapy is where multiple radioactive seeds are implanted in the prostate to deliver radiation to the prostate cancer. These require a minor operation with a general anaesthetic to implant. The main advantage of this approach is that it delivers a high dose of radiation to the prostate, while minimising damage to the surrounding organs.

Who is suitable for brachytherapy?

Brachytherapy works best for low to intermediate grade localised prostate cancers. The ideal candidate is someone with low grade cancer who is not willing to undergo active surveillance. The seeds need to be placed close together, so are not ideal in larger prostates. Brachytherapy causes some swelling of the prostate which may lead to obstructive voiding symptoms. Men with pre-existing voiding symptoms do not fare well with this treatment as their symptoms can worsen considerably.

Adherence to the following selection criteria is paramount to a good result:

• PSA <10
• Gleason 6 or 7 disease
• Small to midsize prostate gland
• No prior prostate surgery
• Normal urine flow

What are the advantages of brachytherapy?

Appropriately selected patients do very well with brachytherapy

• Minor one-off surgical procedure
• Lower rates of erectile dysfunction than EBRT (about 25%)
• Less side effects than EBRT

What are the disadvantages to brachytherapy?

Like EBRT, there are a few disadvantages to this treatment:

• Not everyone is suitable
• Obstructive voiding symptoms can be troublesome
• Urethral strictures (5%) are very difficult to manage if they occur
• It may be difficult to tell if the cancer is cured
• if the cancer is not cured, further surgery is very challenging and often results in poor functional outcomes

In this video, Dr Eric Klein from the Cleveland Clinic discusses the side effects of radiotherapy and brachytherapy. Dr Klein is one of the world leaders in the treatment of prostate cancer.