If the tumour is localised to the prostate (i.e. The staging tests reveal no evidence of spread), then there are three curative options – not all equally relevant to every case. The first option is radical surgery where a skilled surgeon removes the whole gland at operation. The operation is a moderately large one and recovery times are a month or so – only the first week or so usually in hospital. There are slight risks of major complications, as with any major abdominal operation, and then there are the more specific risks. These include a small risk of incontinence of urine and a risk of sexual impotence, although the modern operation aims to spare the nerves that subserve this function (nerve sparing, radical prostatectomy). For localised prostate cancer, the cure rate of radiation therapy is comparable with surgery. There are those who psychologically feel the need to have their gland cut out but others who do not want a moderate sized operation if the alternatives carry the equivalent chance of cure. The classical form of radiotherapy is the external beam, conventionally fractionated course, which takes place over a period of some seven weeks.
The modern linear accelerator that delivers this type of therapy catches the target volume (the prostate gland) in the cross-fire of three or some times four beams – usually a front beam and two beams coming in from the sides of the patient – to effect a highly concentrated radiation course on the gland/tumour. The patients attends every week day for seven weeks (35-37 treatments , called fractions within the profession) and towards the end of the course he may feel slightly tired, have some symptoms of cystitis (urinary frequency and discomfort) and often some temporary rectal discomfort. These symptoms have been minimised since the routine use of ‘conformal’ methodology of which IMRT is one form (a method of in-field, fine-tuned shielding) –the conformal methodology reduces the dose to the rectum in particular. Following therapy, the PSA falls over six months and the late side effects should be minimal. However, some loss of sexual potency occurs in 30-40% of men – interestingly, this usually responds to Viagra, cialis or other non-hormonal methods.
A third method of curative therapy now has good ten years of follow-up to defend its position side by side with radical surgery and conventional radiotherapy as another acceptable definitve method of therapy. This interstitial radiotherapy implant method, also called brachytherapy (Greek word meaning ‘close therapy’) involves the implantation of radioactive seeds into the prostate gland, where they remain to radioactive extinction delivering an ablative radiation dose to this organ. The ability of a template against the perineal skin to direct the seed deposition in two planes (x and y axes) and a trans rectal ultrasound probe to call the depth of implantation in the third axis (z axis) has allowed very exact seed deposition in the current methodology and it has the advantage of relative simplicity for the patient who can go home the same or next day.
The seeds are implanted under general anaesthesia in a procedure that usually lasts a couple of hours only. Because the radiation dose falls off at the square of the distance from the seed (inverse square law), so a very intense dose is delivered within the gland and yet the surrounding structures receive a much lower radiation dose, thus sparing them damage. In 2003, prostate brachytherapy became the preferred cure option in the USA over radical surgery (radical prostatectomy) and the reasons are to do with the now proven equivalence as regards disease free survival/cure rates and the lesser nature of the post-procedure side effects. For example in our own experience and analysing two hundred consecutive patients implanted at my unit there was no case of urinary incontinence (although one man leaks just enough after urination such as to require a pad inside his underpants) and one man (only) requires to self-catheterise once daily - no other long term problems. These sort of figures are now routine from experienced centres practising brachytherapy and explain why this methodology is becoming more popular than surgery. Having said this, case selection is important as this methodology is not suitable for everyone (those with large galands and obstructive symptoms are particularly unsuitable). In an attempt to reduce the size of a large tumour/prostate gland prior to implant or radical external beam radiation therapy, it is now common for the doctor to prescribe a two month course of anti-androgen (anti-hormone/anti-testosterone) therapy prior to the radiation therapy. There are accumulating data to support this practice in terms of disease free survival advantages for the less good risk patients, and for continuing this anti-hormonal therapy longer term(e.g. two to three years after therapy).. Sometimes,we combine external beam radiotherapy (first) with a brachytherapy boost; this is a a perceived advantageous strategy of spreading the radiation dose wider over the first 2/3 of the dose and then adding a more focal boost to the gland itself – such a policy would seem most sensible for the tumours filling the gland and for which there might be early transcapsular spread (albeit not shown on the staging MR scan). From the foregoing it is clear that for the patient with localised prostate cancer there are three types of potentially curative therapy.
How does the doctor and the individual patient make up their minds as to which they should choose? There has been no head to head trial of the three types of therapy but a broad concensus of recommendations is as follows: For patients with small gland and early tumours therein, and PSA values of less than 10 (the PSA being a prognosticator for the future), all three methods seem to have comparable cure rates that should be up in 85%+ for such early disease. When the tumour fills the gland and there is extracapsular spread seen on the MR then external beam radiotherapy is the preferred option – nowadays preceded by anti-hormone (antiandrogen) therapy (as above). Certain other considerations apply: The patient who will not accept a risk of urinary incontinence might be best advised to accept a non-surgical option. Other forms of treatment such as cryotherapy of the prostate and laparoscopic prostatectomy are not well validated alternatives to the conventional surgical and the radiotherapeutic (conformal external beam and brachytherapy) options, (i.e. there is no long term outcome data to prove that they are equivalent to the others). Further details obtainable from Dr. P. N. Plowman at St Bartholomew's Hospital, London For further considerations , see Research and Development section.
