Studies suggest that about 20% of prostate cancer cases have a familial component and this is commonly due to the inheritance of faulty tumour suppressor genes such as p53. The majority of cases, however, are environmental in origin, ie. due to exposure of the body over long periods of time to elements which can cause damage. Migration studies suggest that the biggest environmental factor is a high fat diet.
While occasionally prostate cancer is seen in the chips of prostatic tissue removed during an operation designed to improve urinary flow (TURP), increasingly prostate cancer is diagnosed by men undergoing a biopsy of the prostate. The indications for carrying out a biopsy of the prostate are either an abnormal feeling prostate or a raised PSA blood test.
Once a diagnosis of prostate cancer is made, the pathologist looks at the shape or architecture of the affected tissue under the microscope and assigns it a grade according to how abnormal it looks. This “Gleason grade” comprises two numbers, each from 1 to 5, and these are totalled to give a “Gleason score”, from 2 to 10. There is a good correlation between the score and chance of the disease to progress. An American urologist called Peter Albertson looked at how Gleason score affected lifespan and accordingly he developed tables which show that once the score is 7 or above that survival is more significantly affected.
If the tumour is localised to the prostate then there are a number of treatment options available. If the Gleason score is low, then “active surveillance” or “watchful waiting” may be appropriate, at least for a time. Radical prostatectomy and radical radiotherapy (or a variation of this called brachytherapy) are other options. Nobody has done a big enough, well conducted trial to show which treatment is best, but there is fairly recent evidence in a trial from Scandinavia (Bill-Axelson 2005) that patients undergoing surgery fared better in terms both of survival and lower progression rate than those in a surveillance program.