The PSA test is a simple blood test which is frequently carried out as a screening test to detect the presence of an enlarged prostate gland and of prostate cancer. Although the test cannot in itself be used for diagnosis it is an excellent indicator and, along with other screening tests, PSA testing can suggest the need for additional investigation.

PSA testing is usually recommended for men in high risk groups (such as those with a family history of prostate cancer) once they reach the age of about 40 to 45 and for men in general over 50 years of age.

A single test will provide a snapshot of of the level of prostate specific antigen in the blood and could indicate a problem immediately if you record a particularly high PSA score. However, in the majority of cases, and where a prostate problem may be in its initial stages of development, a single test result will turn out to be inconclusive and another test will usually be suggested a few weeks later. Indeed, ideally testing should be carried out at regular intervals 2 or 3 times every year so PSA levels may be seen over time.

If you record a normal PSA score then all is well, but once your PSA levels begin to rise they have to be watched very closely. The speed with which PSA levels rise is often called the 'PSA velocity' and as long as the rise is steady and the velocity slow then it is again often sufficient merely to monitor the situation as numerous things can influence levels of PSA and seemingly increasing levels will often return to normal in time.

However, if PSA readings begin to increase rapidly and the velocity is said to be high then further investigation is necessary.

This pattern of PSA testing and monitoring has been done for some time but, while the test has long been held as a good indicator of the requirement for additional investigation, it was not until quite recently that we have been in a position to link specific PSA velocity readings to prostate cancer in a fashion which can predict how aggressive prostate cancer is.

In a recent study data about 950 men with prostate cancer who had undergone either surgery of radiation treatment at four hospitals between 1988 and 2004 was analyzed.

In all cases each patient had been diagnosed as suffering from aggressive prostate cancer on the basis of a single very high PSA score, a noticeable rise in PSA velocity during the year prior to diagnosis, a biopsy indicating signs of an aggressive cancer at cellular level, the presence of an advanced stage tumor or a combination of two or more of these pointers.

This study also looked at the outcomes for all of the patients and found that a rapidly increasing PSA score which jumped by 2 or more points in a year was the best indication or the presence of an aggressive cancer.

Up until now we have been able to connect increasing PSA scores with an indication of the possible presence of prostate cancer but it has been necessary to guess to some extent about whether such a cancer is likely to be aggressive and need correspondingly aggressive treatment.

Now however we can say with a fair degree of certainty that where a PSA score increases by 2 or more points in a year then prostate cancer is almost certainly aggressive and requires quick and vigorous treatment.