London: A new approach to cancer treatment which radically increases the effectiveness of radiotherapy has been identified by researchers.

The study, published in the journal Cancer Research, showed that treating mice with certain drugs improved the stability of blood vessels in the tumours.

Normally, blood vessels in tumours are badly developed, weak and twisted, and as a result cancer cells have lower oxygen levels than normal cells. But by using drugs to improve the blood vessels, the scientists at the Gray Institute for Radiation Oncology & Biology of the University of Oxford increased the oxygen concentration inside the tumour, an effect that boosts tumours’ sensitivity to radiotherapy.

A better, more stable blood supply in the tumour also enables better delivery of chemotherapy drugs to the cancers.

“We are very excited to have uncovered this brand new approach to cancer treatment, where the drugs prime the cancer cells for radiotherapy,” says professor Gillies McKenna, director of the Gray Institute.

“It’s a counterintuitive technique because you might expect that by increasing an oxygen supply to tumour cells you would help them grow, but actually by oxygenating the cell with a better blood supply we enable radiotherapy and chemotherapy to do a better job of killing them.”

The scientists tested the effects of four drugs which are in clinical use or under development for cancer therapy. The drugs block a cell signalling pathway which is commonly activated in cancer cells.

The drugs were given to the mice at doses which did not alter tumour growth but the effects of them acted to increase the blood supply to the tumours.

“Previous work by our group had shown that treatment with some of these types of drugs could improve radiotherapy, but it was not understood how. Now with the new understanding, strategies could be developed to use these drugs to soften up tumour cells before treating them with radiotherapy,” professor McKenna added.