Diagnosis, management and screening of early localised prostate cancer

Abstract

The incidence of prostate cancer is rising worldwide, caused mainly by demographic factors, particularly the increasingly elderly population and, more importantly, the increasing number of cases identified following prostate specific antigen (PSA) testing. It is commonly quoted that many more men die with prostate cancer than of it. Autopsy/post-mortem studies show that while a very high proportion of elderly men have histological evidence of the disease, a much smaller proportion develop clinically apparent cancer. The natural history of prostate cancer is poorly understood, but progression appears to be related to stage and grade of tumour. Prostate cancer can be diagnosed by digital rectal examination (DRE), serum PSA test, and/or transrectal ultrasound (TRUS), with confirmation by biopsy. Each test identifies a proportion of cancers, with higher rates of detection when they are used in combination. The tests are also used to determine which tumours are localised within the prostate and are, thus, potentially treatable. Unfortunately, clinical staging is unreliable, with approximately one half of all tumours upstaged following surgery. Three major treatment options are available for localised prostate cancer: radical prostatectomy, radical radiotherapy and conservative management (involving monitoring and treatment of symptoms). Although radical treatment rates are rising, good quality evidence concerning their comparative effectiveness and cost-effectiveness is lacking. Observational studies of highly selected patient groups suggests that there may be a slightly lower mortality rate following radical treatments compared with conservative management, but there has been very little research into treatment complications and quality of life of men after any of the treatments. In the past, investigations of prostate cancer were reserved largely for patients exhibiting symptoms, but the introduction of the PSA test has opened up the possibility of screening healthy men for the disease. Observational studies suggest that DRE and PSA, combined with TRUS and biopsy, can identify localised prostate cancer in 3-5% of men, although the tests do result in a number of false positives and negatives. Major questions remain concerning the natural history of the disease, potential costs (financial, social and psychological) of a screening programme, and the effectiveness and cost-effectiveness of treatments for localised disease. The lack of good quality data and the strength of these concerns means that population screening for prostate cancer cannot be recommended.