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.
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'.
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.
them identify added and deleted regions of DNA across the genome that typify cancers
with a high chance of relapse.
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'.
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.
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.
trials will be needed to confirm the results and assess the test's clinical