Gene test can predict prostate cancer recurrence

A genetic test has been developed to predict the likelihood of prostate cancer returning after treatment. The test, which looks for 'genetic signatures' often found in recurring cancers, is in the early stages of development but may help doctors better assess treatment options for prostate cancer patients.

'Existing methods for identifying high risk patients are imperfect, so new tests are required that are better at predicting which patients will have their cancer recur', said Professor Robert Bristow of the University of Toronto, presenting data on the test at a radiotherapy conference. 'These men can then be offered additional treatments, such as chemo- and hormone therapy'.

To develop the test, the researchers performed DNA analysis on biopsies of 126 men with prostate cancer before and after surgery and followed their disease progression for an average of eight years.

This helped them identify added and deleted regions of DNA across the genome that typify cancers with a high chance of relapse.

Professor Bristow said: 'This is the first report of a test using this information derived from biopsy samples that can predict with close to 80 percent accuracy which men are at high or low risk of their prostate cancer recurring'.

The researchers also looked at tumours' oxygen content as another potential marker for how the disease would progress. They found that hypoxic, or low-oxygen-level tumours were associated with high levels of relapse.

'Importantly, we found that when we combined the signature with the additional information about the tumour's oxygen content, this made the genetic test even more accurate', Professor Bristow said.

Men with low hypoxia and few genetic changes had a 93 percent chance of being cancer-free after five years. This dropped to 49 percent for men with highly hypoxic tumours and many genetic alterations.

Further trials will be needed to confirm the results and assess the test's clinical usefulness.