Prostate cancer, in contrast to Benign Prostate Hyperplasia (BPH), does not draw attention to itself by giving rise to urinary symptoms. By the time the characteristic features of bone pain and haematuria (blood-staining of the urine) appear, the disease is too advanced for cure. Early detection - while the disease is still at a curable stage - is therefore essential. Thus far, however, no foolproof test to detect prostate cancer is available.
Screening for cancer
Until we have more definitive research studies, screening populations for prostate cancer (as is done for cervical cancer in women using PAP testing) is not recommended. However, a form of screening, termed ‘case finding’, is utilized whereby asymptomatic men in the susceptible age group are offered the best test currently available to detect the condition.
The PAP Test for Men
At present, a blood test that measures the amount of Prostate Specific Antigen (PSA) in the man's blood is done - together with a Per Rectal Examination or Digital Rectal Examination where the physician inserts a gloved finger into the man's rectum to feel for nodules on the surface of the prostate gland. (PSA AND PRE– the P.A.P. Test for men).
The test is not foolproof . Twenty percent of prostate cancers do not produce an elevated PSA so both components of the test are essential . It is also important to note that a man's PSA rises with age - so the acceptable level of PSA for a 66 year old is higher than that for a 45 year old. The previously accepted "cut off point", where a level greater than 4.0 ng/L was considered indicative of cancer, is no longer considered accurate. (TABLE 1). Since there are several causes for a raised PSA, it is usually advised that if a man is found to have a higher than expected level of PSA in his blood, he repeat the blood test after a few weeks to make doubly sure that it is really higher than normal.
Prostate biopsy
If either the PSA is abnormal or the prostate feels hard or nodular, the patient should be referred to a urologist for assessment so biopsy of the prostate could be considered. In fact, the most accurate test for prostate cancer is a biopsy of the gland - where a large bore needle is inserted into the prostate gland under anesthesia and a number of specimens of prostate tissue taken for examination under the microscope. However, biopsying every male over a certain age to detect prostate cancer is not a feasible option. Having the blood test for PSA and the rectal examination (PRE or DRE) is the best method currently available to identify those men who have a significantly high chance of being detected to have cancer if they underwent prostate biopsy.
Future
Research is currently underway to discover more accurate methods of detecting prostate cancer. Looking for the ratio between the blood level of Free PSA and Total PSA is one - as is measuring the rate of rise of PSA over a period. Identifying a more sensitive and specific blood test would certainly be helpful - but until we do have such a test, it is certainly wise for a man, once he gets over fifty years, to have an annual 'PAP Test' done.
It may well prevent him dying from prostate cancer.
