New technology 'halves tumour risk'

22 September 2008 04:11pm

Radiation therapy based on the technology behind the Large Hadron Collider 'Big Bang' experiment can halve the chances of cancer patients developing a secondary tumour, say scientists.

The treatment delivers a beam of protons - the positively charged central cores of atoms - at a cancer site instead of the X-rays normally used for radiotherapy.

Protons are also employed in the Large Hadron Collider (LHC), the giant particle accelerator switched on earlier this month in Geneva, Switzerland, amid a fanfare of publicity.

Proton therapy is more precisely targeted than conventional radiotherapy, so that in theory it should be less damaging to healthy tissue around a tumour.

But there has been concern about the effect of "scatter radiation" - the generation of neutron particles caused by proton bombardment. There were fears that these scattering particles might trigger secondary cancers.

The findings from the new study suggest that scatter radiation is not a problem.

Of 503 patients given proton therapy at the Harvard Cyclotron Laboratory in Boston, US, 6.4% developed a secondary tumour. In comparison, 12.8% of 1,591 matched patients treated with conventional radiotherapy developed secondary malignancies.

The Harvard cyclotron facility has closed since the research was carried out.

Research leader Dr Nancy Tarbell, from Massachusetts General Hospital in Boston, said: "This study could have a substantial impact on the care of patients. Since cancer patients are surviving for longer periods of time, side effects of therapy are becoming increasingly important for doctors to consider when developing treatment plants."

Further studies were now needed, said Dr Tarbell, who presented the findings at the annual meeting of the American Society for Therapeutic Radiology and Oncology in Boston.

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