What is prostate brachytherapy?

Brachytherapy is a form of radiotherapy treatment for early, localised prostate cancer, i.e. cancer that has not spread outside the prostate gland. The treatment involves inserting tiny radioactive capsules or 'seeds' (slightly smaller than a grain of rice) into the prostate gland under anaesthetic. This allows radiation to be targeted directly at the prostate tumour and minimises the effects of unwanted radiation affecting surrounding healthy tissues. It is a simple procedure that usually only needs an overnight stay in hospital. Patients recover quickly, and it has fewer side-effects than other treatments for prostate cancer such as removal of the prostate (a procedure known as radical prostatectomy), which requires a longer stay in hospital, or external radiotherapy, which requires a lot of visits to hospital over many weeks for the treatment. Brachytherapy is becoming widely available for treating prostate cancer in hospital centres in the UK because of its effectiveness and quality-of-life benefits compared to other treatment options.

How is prostate brachytherapy performed?

The amount of radiation, and where it has its effects in the prostate tumour, are controlled by the number of seeds implanted and their very precise positioning. This will vary from patient to patient. The number of seeds required and their position is determined by specialist examination and measurement of the size of the patient's prostate gland by an ultrasound scan. There are two stages to the procedure - a planning stage and the implantation itself. Some hospital centres will do the planning and implantation at the same time (Single Stage approach); other centres do planning first, and then 3-4 weeks later they will do the implantation itself (Two Stage approach).

The planning stage, also called a prostate volume study, measures the size and shape of the prostate. This information helps the specialist team to work out how many radiation seeds to use and where to put them.

The second stage is the seed implantation itself. The seeds are implanted using 15-25 fine hollow needles which are pushed through the skin behind the scrotum and in front of the anus (an area called the perineum). Pictures from an ultrasound probe in the rectum help the doctor to see exactly where each delivery needle is going. Between 60-120 seeds are passed through the needles, either individually, or as strands of several seeds linked together. When the seeds are in the correct place the needles are removed, leaving the seeds behind. The seeds stay in the prostate, slowly giving out radiation until they are no longer radioactive.

For both the prostate volume study, and the implant procedure, a general anaesthetic is needed. With prostate brachytherapy it is possible deliver a higher dose of radiation to a prostate tumour than is possible with conventional external beam radiotherapy, but because the sources of radiation are localised, tissue damage in nearby organs is minimised.

After the implant procedure

Prostate brachytherapy has fewer side-effects compared with other treatments for localised prostate cancer such as surgery or external beam radiotherapy, and the patient can usually return to normal activity the next day. Immediately after the implant procedure, patients may experience some or all of these side-effects:

• soreness, bruising and discolouration in the area between the scrotum and anus (perineal area)
• blood in the urine and semen
• a burning sensation when passing urine.

An ice bag placed between the legs will help to reduce the swelling caused by the procedure. The patient will be encouraged to drink plenty of water (this helps to flush out the bladder and reduce any blood clots) and will receive medication to help him urinate; antibiotics will also be prescribed to prevent infection. Due to the anaesthetic, patients should not drive for 24 hours.

About a week after implantation, a reaction to the radiation from the seeds may cause increased frequency of urination and an increased 'urge to go'. Urination can be painful and the flow of urine may be less than normal. If these effects are severe, medication is available to help. A small proportion of patients (around 15%) may develop acute urinary retention and will need a catheter to help them pass urine. These side-effects are likely to last for around 4 — 6 weeks, but some urinary symptoms may go on for 6 — 12 months. However, most patients find the discomfort is not too troublesome and can still carry on with a normal life. Incontinence after prostate brachytherapy is rare, occurring in about 1 — 2% of patients. Some patients feel as though they are constipated, or have an increased urge to open their bowels, an effect that may due to the swelling in the prostate gland. This usually settles down on its own.

Longer-term effects

The two most troublesome side-effects associated with all treatments for prostate cancer are urinary incontinence and impotence (also called erectile dysfunction or simply ED — this is the inability to achieve a satisfactory erection of the penis).

Radical prostatectomy (i.e. surgery) causes these side-effects most often (ED occurs in 50—80% of cases), followed by external beam radiotherapy. Prostate brachytherapy is least likely to induce these side-effects. Erectile dysfunction after brachytherapy only occurs in around 20—30% of men under the age of 60 years, although it does occur more often in men aged over 60 years. Erectile dysfunction usually responds well to treatment, and your general practitioner (GP) can advise on this.

LDR brachytherapy scored highest in a recently published health related quality of life (HRQoL) study. Data collected from 625 patients through self completed questionnaires following treatment indicated urinary incontinence scores of 85.9, 85.5 and 73.4 (for LDR brachytherapy, external beam radiation and radical prostatectomey). It should be remembered that higher scores indicate more favourable HRQoL outcomes. Similarly LDR brachytherapy scored best with regard to preservation of sexual function following treatment. Mean scores of 37.8, 28.0 and 25.1 for brachytherapy, external beam radiation and radical prostatectomy were recorded. ¹

Do the seeds have to be removed?

No. Once in place, the seeds are not removed; they are permanent but harmless implants. The seed capsules are made of titanium which is inert and does not cause irritation inside the body. Each seed contains a radioactive isotope of iodine with a half-life of approximately 60 days. This means that the amount of radioactivity decays to 50% (half) of its initial level after 60 days. After about 9-12 months, the level of radioactivity will have decayed to a very low level and the treatment can be considered to be complete.

During the period of treatment, although the seeds are radioactive the patient is not. The implants carry no significant risk to the health of the patient's family or friends. There are no restrictions on travel or physical contact with other adults. As a precaution, and for peace of mind, patients may be advised during the first two moths of treatment to avoid sitting close to children or pregnant women, but physical contact for short periods is allowed. Patients are advised to use a condom for the first two or three times they have sexual intercourse after implantation; ejaculation may be painful in the first couple of weeks, but this will settle in time.

How will I know if prostate brachytherapy treatment has worked?

Patients are monitored after their implant by means of regular blood tests. These test for prostate-specific antigen or PSA, a very sensitive indicator that shows whether there is any active prostate cancer present. Patients' PSA is first measured 3 — 6 months after the implant procedure, although the levels at 12 — 18 months are the most important and give the most information on whether the treatment has been successful. The PSA level will fall slowly over one to two years following successful treatment, although it may temporarily rise at times before going down. The PSA level will not drop to zero because after brachytherapy patients still have their prostate gland and the normal benign (i.e. non-cancerous) prostate tissue will continue to release a small amount of PSA into the bloodstream.

How do I know if prostate brachytherapy is right for me?

The decision on whether prostate brachytherapy is the right treatment is a complex one to make. All patients should review and discuss the options available to them with their consultant urologist or consultant oncologist (cancer expert). Providing the prostate cancer is at an early stage, there is no need to make a hasty decision; the important point is to make the right, informed decision. The advice you will receive as to whether prostate brachytherapy is the best option for you depends on a wide range of considerations. Some of the most important ones are listed here, but other factors may be important for individual cases:

• the man should be in good health with a 10+ year life expectancy
• the cancer should be confined to the prostate gland and at an early stage
• the PSA should be below 21 ng/ml (men with a PSA score of less than 10 do well; men with a PSA of 10 — 20 do fairly well; men with a PSA of over 20 do poorly).
• ideally the Gleason score (a scoring system used by doctors to assess how aggressive the prostate cancer is) should be below 8 (men with a Gleason score between 5 — 6 do well, men with a score of 7 do fairly well, men with a Gleason score between 8 — 10 do poorly)
• the prostate size should ideally be less than 50 ml. If it is more than 50 ml then some centres will use hormone treatment to shrink it; there are however some centres who do not have this restriction and they have successfully treated larger prostates, especially if a Single Stage approach is used (for further information see section on UK brachytherapy centres > London region > Guy's and St Thomas' NHS Foundation Trust).
• some centres would exclude patients who have had previous prostate surgery such as transurethral resection of the prostate (TURP) which could increase the risk of post-implant incontinence, however some other centres have successfully treated patients with previous TURP with no increase in side-effects (for further information see section on UK brachytherapy centres > London region > Guy's and St Thomas' NHS Foundation Trust).
• patients should have few urinary symptoms as assessed by a questionnaire - the International Prostate Symptom Score (IPSS) - this should be less than 20 out of a maximum of 35 (men with an IPSS between 0 — 10 do well, men with an IPSS between 9—19 do fairly well, men with an IPSS of more than 20 do poorly)
• patients should be able to flex their hips to 90 degrees
• patients should not have previously been treated with external beam radiotherapy to their prostate.

The advantages of prostate brachytherapy — a summary

With brachytherapy, the patient usually only has to attend hospital twice: once to have the assessment scan (as a day case), and secondly to have the seeds implanted followed by an overnight stay. Some centres will do the assessment and the implant on the same visit. Most patients are able to return to routine daily activities within a few days.

By contrast, patients undergoing conventional radiotherapy are likely to have to attend over 30 hospital visits. Patients who have their prostate gland removed surgically can expect to be in hospital for 3—7 nights and go home with a urinary catheter in place to prevent urine retention in the bladder. The catheter is removed after 1—3 weeks. Men who have had a radical prostatectomy can be off work for 6—8 weeks, and most cannot drive for 4 weeks after the operation.

In clinical studies, prostate brachytherapy has been shown to be highly effective for the treatment of early prostate cancer. The 10-year disease free survival expectancy following brachytherapy is similar to that achieved with conventional beam radiotherapy and radical prostatectomy (reported rates vary between 50% and 94%), but this is achieved with a lower risk of some of the complications associated with surgery and conventional beam radiotherapy. Recently, 15-year survival figures have been published for men who received brachytherapy combined with external beam radiotherapy for the treatment of localised prostate cancer. The overall survival rate in 223 patients at 15 years was 74%. When the patients' level of risk was taken into consideration, the 15-year survival rates were 88% in the low-risk subgroup, 80% in the intermediate-risk subgroup, and 53% in the high-risk patients. The doctors who conducted and published this study (Sylvester JE, Grimm PD, Blasko JC et al, 2007) stressed that they expect relapse-free survival to improve further with modern brachytherapy equipment and techniques.

Brachytherapy as a treatment for prostate cancer was developed in the USA, and over 50,000 prostate cancer patients a year are treated with brachytherapy in the USA. There is now considerable and growing experience of this procedure in the UK and Europe. As a consequence, the risks and benefits of the procedure are well understood and can be explained to you at your hospital appointment.

Hospital staff roles

Patients who receive treatment for prostate cancer will see a number of healthcare professionals at their hospital. The roles of the different doctors and support staff are explained below:

Consultant: a senior doctor who has overall responsibility for your particular care programme. Your appointments may not always be with the consultant; sometimes you will see someone else in their team.

Radiologist: a senior doctor who specialises in X-rays and interpreting body scans. They will also perform the ultrasound for planning and guidance of the brachytherapy implant procedure.

Oncologist: a doctor who specialises in treating cancer. Some oncologists specialise in particular types of cancer treatment.

Urologist: a doctor who specialises in treating problems of the urinary tract.

Registrar: a senior member of the medical team who works closely with a consultant within a particular specialty, for example, 'care of the elderly' or 'oncology'.

Foundation Year doctor (FY1 or FY2, used to be called house officer): a qualified junior hospital doctor working during their training period. They spend around 4 months in each specialty area of medicine. A ST doctor (used to be called senior house officer (SHO)) has spent more time in medicine and has usually started to develop an area of specialty.

Nursing staff: qualified nurses who look after your clinical care. Health care assistants support the nursing team.

Nurse specialist: a nurse who is trained and experienced in working within a particular area of cancer.

Physicist: a healthcare scientist who calculates the number of seeds and their position for your treatment, and is also responsible for radiation guidelines.

References