Gene testing could improve screening programme in future

Calculating individual genetic cancer risk and taking age into account could mean fewer women would need to be screened for breast cancer, according to research published in the British Journal of Cancer¹, today (Wednesday).

Based on work funded by Cancer Research UK and the European Community (COGS project), researchers say this new screening concept would still detect the same number of cancers but could also potentially reduce some of the risks associated with screening – such as false positives and subsequent anxiety – as well as saving the NHS money.

The researchers used a statistical model to compare a hypothetical age based screening programme and the number of cancers potentially detected with how many cancers would be detected if people were invited to screening based on their genetic risk of cancer as well as their age.

In England almost 31,000 cases of breast cancer are diagnosed in women aged 35 to 79. Screening all women between 47 and 79 – in a hypothetical age based screening programme – means 65 per cent of women aged 35 to 79 would be screened. And, if all women went for screening and the test was 100 per cent perfect, 85 per cent of cancers diagnosed in the 35 to 79 age group would potentially be detected.

But by using a genetic test to identify women at a higher risk of breast cancer the researchers found that the number of women screened could be reduced without reducing the number of cancers detected by screening².

In theory, it could mean that fewer women would be screened and has the potential to reduce some of the risks linked with screening such as over diagnosis and overtreatment³.

Lead author Dr Nora Pashayan of the PHG Foundation and Cancer Research UK training Fellow, said: “This is an alternative approach to the existing screening programme and might even have the potential to reduce over-diagnosis, and in turn, lower costs.

“For our model to be used women would need to have a genetic test before the age of 35. This would be a simple blood test to identify genetic risk and, depending on the results, the age at which they should be invited for screening could be calculated. For some women this would be when they’re 35, for others not until they’re in their 50s or 60s or even later.

“This approach means that screening women at high risk of the disease when they are younger will pick up some cancers earlier. These cancers tend to be more aggressive so the earlier they are picked up the better.

“And as more genetic information becomes available, the efficiency of screening approach that takes account of genetic risk will further improve”.

The researchers also calculated a statistical model of how a similar approach might be relevant to prostate cancer screening if a programme were to be introduced in the UK.

Professor Paul Pharaoh, a Cancer Research UK expert in genetics and study author, said: “Even though our analysis is based on a theoretical model which assumes that there’s a 100 per cent attendance for breast cancer screening it still shows that personalised screening has the potential to reduce the disadvantages of a screening programme without losing any of its benefits. We now need more research to find out what effect genetic testing would have on over-diagnosis and whether deaths from breast cancer would fall. And we also need to consider the wider ethical and legal issues with more personalised screening”.