The lifetime risk of acquiring prostate cancer is an alarming 30% but only 10% of men develop it as a clinical disease and only 3% of men die because of prostate cancer. Although it has a reputation, including amongst doctors, of being a condition that men die with (rather than because of it), the reality is that 10,000 men a year die of prostate cancer in the UK. Prostate cancer overtook lung cancer as being the commonest cause of cancer-related deaths in men approximately 10 years ago. If prostate cancer is present in a man with a life-expectancy of at least 10 years it should be identified as soon as possible and treated with curative intent.
Causes of Prostate Cancer
The cause of most cancers, including prostate cancer, remains enigmatic. Genetic studies suggest that 42% of cases are familial i.e. the inheritance of faulty tumour suppressor genes, such as p53, down through the generations. Exposure to environmental carcinogens such as heavy metals and working in the nuclear power industry are unusual causes. Migration studies suggest that the strongest influence, and the only one which we can influence, is our Western diet.
Coping with the diagnosis
Although it is upsetting to be diagnosed as having cancer, prostate cancer is a slow-growing cancer and you are fortunate in having had it diagnosed at a potentially-curable stage. You now need to choose one of the three treatment options available. This is a very important decision and you should take as much time as you think you need to do make it. Your doctor will help you make the right choice for you but cannot make this decision for you.
The Gleason grade
The tumour is graded using the Gleason ‘system’, which assigns a number from 2-10, depending on the microscopic appearance of the cancer cells. This appearance predicts the aggressiveness of the cancer. The higher the score, the more aggressive the tumour.
Survival from prostate cancer at 10 years based on the outcome of 59,876 patients (Lu-Yao, 1997).
Aggressiveness |
Gleason Score |
Surgery |
Radiotherapy |
Watchful Waiting |
Low |
2 - 4 |
94% |
90% |
93% |
Moderate |
5 - 7 |
87% |
76% |
77% |
High |
8 - 10 |
67% |
53% |
45% |
New markers of aggressiveness
The notion of not being able to distinguish the ‘tigers’ from the ‘pussycats’ in relation to prostate cancer is untrue. For most patients with prostate cancer the need to intervene or not is clear.
However, although the Gleason grade gives an excellent prediction of aggressiveness of a prostate cancer, biopsies sometimes contain cells which are unrepresentative of the whole cancer.
Markers which appear to correlate well with tumour aggressiveness include the gene sequence variants 8q24 & 2p15, the genes E2F3, BCL2 and BCL6 and the proteins they code for. It is likely that microarray analysis on biopsy tissue will be used in the future to identify tumours which are particularly aggressive and need more than one treatment modality (e.g. surgery plus radiotherapy) or particularly slow-growing, which might persuade a surgeon to advise against radical treatment in a man aged 70, for instance.
Why do anything?
A recent 10 year study from Scandinavia comparing radical prostatectomy and watchful waiting has found that surgery reduces disease-specific mortality, overall mortality, and the risks of metastasis and local progression. The absolute reduction in the risk of death after 10 years was small, but the reductions in the risks of metastasis and local tumor progression were substantial (Bill-Axelson, 2005).
