Britain's biggest cancer research charity has thrown its weight behind mass genetic screening for predisposition to the disease after research suggested that many individually minor gene variations, inherited together, can multiply cancer risk.
The approach, which initially focuses on breast cancer, would prove controversial because it would divide healthy women into "cancer-prone" and "less cancer-prone" bands. Critics argue that it would encourage fatalism in the former and irresponsibility in the latter.
The charity, Cancer Research UK, said lives would be saved by enabling those most at risk to be monitored more intensively and nipping early stage cancers in the bud.
Paul Pharoah, the lead researcher in the new study - funded by the charity - said he would support putting healthy but genetically at risk women on powerful anti-cancer drugs like tamoxifen.
Details of the research are published today in the journal Nature Genetics. "Our results showed that many common genes seem to add together to raise the risk of breast cancer. In the future, we should be able to test for a selection of these, accurately identifying those women who have a high chance of getting the disease.
"Rather than spending lots of money on a one-size-fits-all breast screening programme that examines some women too often and others not often enough, we could plan screening according to a woman's risk. And for women with a very high risk of the disease, drugs like tamoxifen may be useful preventative agents."
The study, carried out at the Strangeways Research Laboratories in Cambridge, is a statistical analysis of breast cancer rates among relatives of 1,484 women with the disease. It concluded that the main hereditary risk of breast cancer came from many different genes which were cumulatively dangerous.
Mutations in two genes - BRCA1 and BRCA2 - give a very high risk of breast cancer, but are present only in a few people.
The Cambridge team's results suggest that there is a much larger group of genes which could be used to identify a high risk group, comprising 12% of the female population, which gives rise to half of all breast cancer cases.
·Advances in mixing anti-cancer drugs could lead to a "new breed" of therapy which could offer an alternative to conventional chemotherapy, scientists at Cancer Research UK's Institute for Cancer Studies at Birmingham University, said yesterday.
