Prostate Cancer

The prostate specific antigen (PSA) test was elevated and required further investigation. The patient was referred to a urologist, probably facing a Trus (transrectal ultrasound guided) biopsy. This involves an ultrasound probe into the rectum and then, guided by the ultrasound images, inserting a fine needle along the probe, through the rectum wall and into the prostate, to remove a tissue core, repeating a number of times until samples from different prostate regions are sampled. Side effects include septicaemia and constant pain.

The prostate is a walnut sized gland sitting at the base of the bladder and surrounding the urethra - the tube running from the bladder to the outside. 75% of men in their 70s have urinary symptoms caused by a benign enlarged prostate. Some 3,000 men are diagnosed with prostate cancer in Ireland each year. An elevated PSA does not mean the patient has prostate cancer, so the PSA test is not suitable as a screening test. The decision to monitor or treat an early stage cancer is not straightforward. One study followed patients for 10 years and found no difference in death rates between men who were chosen at random to have surgery or radiation, and those whose cancer was actively monitored. Death rates were low overall, only 1% of patients were dead 10 years after diagnosis.

Clearly non-invasive tests are needed. Evidence shows that performing multiparametric (mpMRI) scans before biopsy is an effective way of detecting prostate cancer whilst providing accurate guidance for a subsequent biopsy if the scan identifies possible lesions.

The PROMIS trial involved 740 men with clinical prostate cancer who did not have a prostate biopsy. They were tested so that an mpMRI scan prior to biopsy could identify men who might safely avoid the invasive test, in fact 25% of men so referred, on suspicion of prostate cancer were able to avoid a primary biopsy. The mpMRI findings would allow 18% more cases of clinically significant cancers to be detected.

The mpMRI test could replace the PSA at least an alternative to the invasive Trus test.