Prostate news article, January 2006
THE PROSTATE CANCER PATIENT'S DILEMMA Dr Mark R Feneley Senior Lecturer in Urological Oncology |
Nobody should have cancer treatment without a confirmed diagnosis - but can the diagnosis be made too early? In the PSA era, the diagnosis of prostate cancer is generally made by prostate biopsy before the onset of symptoms. The benefits of curative therapy are accrued gradually with long-term survival. However, not all men with tumours detectable by biopsy would, if untreated, ever develop the symptoms or the life-threatening complications of prostate cancer. Sometimes this is due to the competing effects of lack of physical fitness and poor health - hence the importance of timely attention to diet, exercise and lifestyle. Many tumours in the very early stages can exist in relatively quiescent states for long periods of time, and it may be impossible for doctors to be sure that treatment is necessary. But sadly for men who do not have their PSA checked and are eventually diagnosed with cancer, treatment is frequently too late to be curative.
Even before the era of widespread PSA testing and radical treatment of early stage prostate cancer, the diagnosis of prostate cancer exceeded its mortality by approximately two-fold. Now, with PSA testing and earlier diagnosis, this ratio has increased to nearly three-fold. When prostate cancer is diagnosed very early in its development, the risk of clinical disease may remain very low for many years - particularly in men with relatively low grade lesions - and in some cases there may in fact be no risk. The pathologist is often ill-equipped to identify life-threatening tumours in these very early stages, particularly in small biopsy specimens. Life expectancy, other medical conditions and quality of life issues are always significant considerations. Thus some patients may choose to defer intervention, particularly if they are older with so-called low-risk disease. For others, any risk is intolerable and the only acceptable option is immediate treatment. This underlies the need for more reliable science.
There are exciting opportunities for research to change the patients’ dilemma - see the accompanying article entitled Breaking the Molecular Code for Prostate Cancer. In the very early stages of prostate cancer development, the risk of clinical disease may be a modifiable rather than a constant or inevitable risk. This possibility may enable immediate treatment to be avoided, or safely deferred, according to the level of biological risk. This biological risk relates to a tumour’s molecular behaviour, and powerful new techniques are now being developed that may in future provide a “molecular diagnosis” that identifies the pattern of molecular derangement as a prognostic signature. External factors (dietary, environmental, even medical interventions) are known to induce changes in the prostate that may significantly influence so-called pussy cats to become tigers. Research programmes examining the make-up of developing tumours are vital to refine diagnostic and prognostic tools and to develop techniques for detecting molecular damage to the prostate before ‘signatures’ of life-threatening disease are irreversibly established.