New prostate cancer test far more accurate

Oct 18 2005

At present in order to predict prostate cancer outcomes, doctors rely on measures that suggest how far the tumour has spread and how abnormal the cancer cells appear under the microscope.

They may also use blood tests to look for a marker called prostate specific antigen (PSA), but this can be unreliable because some men with prostate cancer do not have a raised PSA level and some men with a raised PSA do not have prostate cancer.

Apparently for every 100 men with a raised PSA, only about a third will have any cancer cells in their prostate.

Also a stable PSA or a drop in the level with treatment for those diagnosed with prostate cancer does not always mean that the cancer therapy is working as PSA levels can fluctuate for other reasons.

Now U.S. researchers say there may be a better marker to indicate when a man has a more aggressive form of prostate cancer.

They say that checking for a protein called MDM2 could improve current testing methods which are less than perfect.

Spotting the most dangerous tumours early so they can be treated is important to improve survival.

The work was presented at the American Society for Therapeutic Radiology and Oncology meeting in Denver, Colorado by Dr Alan Pollack and colleagues from the Fox Chase Cancer Center.

Pollack and his team looked at the amount of a protein called MDM2 in prostate cancer cells to see if this might improve prognosis prediction.

MDM2 is involved in regulating cell growth and has in the past been linked to prostate tumours and other cancers.

It seems that among 469 men with prostate cancer who had been treated with radiation and drugs, MDM2 appeared to reflect which had responded well to these therapies and which had not.

Detectable MDM2 was associated with a doubling of distant cancer spread and a nearly 10% reduction in five-year survival.

Dr Pollack says that new biomarkers promise to strengthen the ability to predict response to treatment, and by identifying more virulent forms of prostate cancer, it may be possible to tailor treatment or develop therapies to target the abnormalities identified.

Chris Hiley of the Prostate Cancer Charity says the research is very welcome even though it is in the early stages.

He says any test that can enable doctors to distinguish clearly between aggressive and slow growing forms of prostate cancer is vital.

Hiley says if this new marker fulfils its promise, doctors will be able to give much clearer, timely guidance to men on their treatment options and what outcomes to expect.

Dr Emma Knight of Cancer Research UK, says that such a test could reduce the need for unnecessary treatment while allowing those men with potentially life-threatening disease to be followed up more rapidly.

Prostate cancer is now the most common cancer to affect men in the UK - more than 30,000 are diagnosed with it each year.