With the introduction of PSA and PCA-3 testing, prostate cancer is being diagnosed earlier than ever before; the corollary to this is that the potential for cure is much greater.
Whilst it is true that for some elderly and frail patients, the diagnosis of prostate cancer is irrelevant (in that it will not progress and threaten within their expected lifetime) for most others the warning signs of a raised PSA, prostatic urinary symptoms (although much more commonly due to benign prostatic disease), positive family history of the disease etc. merits investigation, diagnosis and curative treatment.
This article on prostate cancer treatment is written by Dr Nick Plowman, MD, Senior Clinical Oncologist to St. Bartholomew’s Hospital, and The Hospital for Sick Children, Great Ormond Street, London.
Prostate biopsy (via trans-rectal ultrasound) is the definitive method for diagnosing early prostate cancer and involves 8-12 core biopsies taken from different areas of the gland. The microscopic appearance of the prostate cancer will give a clue as to how aggressively it will grow in the future (Gleason score).
Once the diagnosis of prostate cancer has been made, it is very important to discern whether it is ‘organ confined’ or not and a high-quality MRI scan is important in this regard. Where the capsule of the gland is intact (T1-2 stage disease) management is different from those cases where the disease has breached the capsule and extended outside the gland (T3-4 disease). Similarly, the pelvic MRI scan will show if there is spread to pelvic lymph nodes and a bone scan is used to exclude (as far as possible) spread to bone.
From the investigations discussed so far, the disease has been diagnosed and staged. From these tests, it is also possible to prognosticate into higher and lower risk patients (with regard to potential for later relapse risk). Higher risk patients will have higher PSA levels, higher Gleason grades and a tendency to have trans-capsular spread, whereas lower-risk patients will have low PSA levels, average Gleason scores (6-7) and have no capsular breach or distant evidence of disease outside the gland, on pelvic MRI.
For lower risk patients, radical surgery (by either open or robotic means) has been a popular method of cure for many years, although it is a large pelvic operation and there are definite risks of urinary incontinence and impotence and a lengthy recovery period post-operatively – all of which present drawbacks to the procedure. The microscopic margin-free rates of the robotic surgical series are of some potential concern and it will require long term follow-up rates to discern as to whether the long-term cure rates are as high as for open surgery. Nevertheless, for younger patients with obstructive urinary symptoms it remains an important curative option.
Other lower risk patients are most frequently treated by radiation brachytherapy. In the best-established method of brachytherapy, radioisotope seeds are placed accurately and precisely under vision from a transrectal ultrasound probe into the prostate in a pre-planned distribution, bespoke for the patient’s gland size and shape. The merit of such internal seed placement is that the radiation is deposited at very high dose around each seed and yet the dose falls off fast at the margin of the gland (according to the inverse square law of physics) such that outside the gland the dose to adjacent structures, such as rectum and bladder, is minimised. By this means, it is possible to deposit an obliteratively high therapy dose to the cancer without high risk of harming other structures. The method has become more popular than surgery in recent years as the cure rate is equivalent to surgery but the procedure is much less taxing on the patient with fast recovery times and low complication rates. Some urinary side effects are universal (usually frequency for three months) but the need for a continuing urinary catheter usage past 24 hours is less than 7% in our series and less than 3% at more than one month following the procedure. We have not encountered urinary incontinence or rectal problems and the great majority retain sexual potency (two-thirds at status quo ante).
Our unit established the procedure in London and currently has led the field in the perioperative monitoring and dynamic adjustment of implants during the procedure. In this advance, we monitor seed placement during the operation and, if one or more seed are slightly malpositioned, the new position(s) is fed back into the computer programme and all subsequent seed positions area adjusted (if necessary) to account for this – ensuring optimal final radiation distribution.