Cancer researchers seek safe reduction of radiotherapy

University of Manchester scientists discussed their research aimed at reducing the side effects of radiotherapy without decreasing its effectiveness at the National Cancer Research Institute conference in Birmingham today (Tuesday 2 October 2007).

Around half of patients receive radiotherapy as part of their cancer treatment but the dose is limited by the possibility of causing side effects (toxicity) to the normal tissues and organs that surround the tumour. Some patients are more likely to experience these side effects than others: that is, there is an individual variation in tissue response. Some patients will be very sensitive.

Dr Catharine West, of the University's Cancer Studies research group, and Dr Neil Burnet, of the University of Cambridge, are leading a large multi-centre UK study designed to identify the common genetic variations that are associated with such side effects. The study - Radiogenomics: Assessment of Polymorphisms for Predicting the Effects of Radiotherapy (RAPPER) - is funded by Cancer Research UK and aims to extract DNA from the blood samples of 2,200 patients with a variety of cancers.

Dr West explains: "This is a very exciting development in cancer research. Genotyping studies should provide a means of identifying radiosensitive patients and lead to a greater individualisation of radiation dose prescription to optimise tumour control while reducing toxicity."

Dr West and her team are also involved in a study of patients with soft tissue sarcoma (cancer in the muscles), a rare cancer that accounts for approximately 1% of adult cancers with around 1,200 cases in the UK each year, again funded by Cancer Research UK.

VORTEX - led by Dr Martin Robinson at the University of Sheffield - is a randomised trial to assess if reducing post-operative radiotherapy in patients with soft tissue sarcoma (cancer of the muscle) increases their limb function without compromising the treatment. The Manchester team are using samples from VORTEX to carry out VORTEX-BIOBANK, a study that aims to develop a tumour profile that will identify patients with an increased likelihood of secondary cancer. The team also aims to investigate associations between common genetic variation and a patient's risk of radiation induced side-effects in this particular cancer, as they are doing for a variety of other cancers in RAPPER.

Miss Rebecca Elliott, who will make a presentation about the team's work at the conference today, says: "There is exciting high-throughput technology out there and we are looking at the possibility of individualising patient treatment. The technology allows us to look at the variation and expression of genes to see which genes indicate who will be sensitive to radiotherapy. In future we will have a patient profile - if you have certain versions of genes x, y and z, then you have the chance of getting toxicity one hundred times more than someone with other versions."

"Although we are still collecting samples and are some way off getting our final results, it is an important new pathway in cancer research."