Molecule in cells predicts success of radiotherapy in individual bladder cancer patients

Sep 15 2010

New test hope to personalise treatment for bladder cancer patients

CANCER RESEARCH UK scientists have identified a molecule in cells which could predict the success of radiotherapy to treat individual bladder cancer patients, reveals research published in Cancer Research1 today (Wednesday).

The scientists, who carried out the work at the Leeds Institute of Molecular Medicine, University of Leeds and the University of Oxford2, looked at the quantity of a DNA repair protein called MRE11 in the bladder tumour tissue of 86 patients before radiotherapy.

They found that around 70 per cent of patients with high amounts of MRE11 survived at least three years after radiotherapy compared with around 40 per cent of those with low levels3.

In 20 to 30 per cent of cases, tumours invade the muscle wall of the bladder, requiring either surgery to remove the tumour along with the bladder - called cystectomy - or alternatively radiotherapy treatment. Both treatments lead to similar survival rates4.

Treatment choices are currently largely decided by patient preference and the expertise of doctors as there are currently no means of predicting whether radiotherapy or surgery would be better for each patient. If predictive markers could be identified, patients could be selected for the treatment most likely to benefit them personally.

Study author, Dr Anne Kiltie, now Cancer Research UK clinical group leader at the Gray Institute for Radiation Oncology and Biology at Oxford University, said: "If our findings are confirmed in larger studies, then a clinical trial should be done to see if MRE11 could be used to select patients for radiotherapy or surgery. This could lead to a test being developed to identify if a patient will respond well to radiotherapy and enable doctors in the future to personalise their treatment plan."

The protein MRE11 identifies when DNA is damaged and signals this damage to the cell. Cells in which there is already DNA damage may be more susceptible to further DNA damage and die. Amounts of MRE11 in bladder tumours may predict how well radiotherapy will work since radiotherapy kills tumour cells by damaging their DNA.

In contrast, amounts of protein in cells do not predict the survival rates for surgery. The scientists showed that in 88 patients who had had their bladder removed by surgery, the levels of MRE11 pre-treatment was not linked with survival.

Bladder cancer is the seventh most common cancer in the UK. Each year in the UK around 10,300 people are diagnosed with the disease - around 28 people every day. There are more than twice as many cases of bladder cancer in men than in women.

Dr Lesley Walker, Cancer Research UK's director of cancer information, said: "Cancer Research UK is investing heavily into developing more personalised ways to treat patients based on tiny differences in the genetic makeup of cancer.

"Our researchers are identifying exactly what goes wrong in cancerous cells, and they're making more discoveries such as this. Now they're in the process of linking these discoveries to targeted and increasingly more effective treatments."

Source: Cancer Research UK