Adopting a personalised screening approach for breast and prostate cancer, where both an individual's genetic risk and age are taken into account, could result in fewer people requiring screening, concludes a Cancer Research UK sponsored study published in the British Journal of Cancer.

It is well recognised that the benefits of cancer screening programmes may be offset by adverse consequences such as false -positive results, over diagnosis and overtreatment. Genome-wide association studies (GWAS) have identified genetic variants that are common in the population and confer susceptibility to different types of cancers. In the current study UK investigators, from the University of Cambridge, Wolfson Institute of Preventive Medicine at the University of London, and the Institute of Cancer Research, set out to model the efficiency of a personalised screening strategy based on a combination of age and polygenic risk-profile compared with a strategy based on age alone in both prostate and breast cancers.

Results showed that compared with screening approaches based on age alone, where women aged 47 to 79 years are offered screening, personalised screening of women aged 35 to 79 would result in 24% fewer women being eligible for screening at a cost of 14% fewer screen-detectable cases.

The results for prostate cancer showed that compared with approaches based on age alone where men aged 55 to 79 are screened for prostate cancer, personalised screening of men aged 45 to 79 based on genetic risk factors would result in 16% fewer men being eligible for screening, at a cost of 3% fewer screen-detectable cases.

"Personalised screening strategy based on age and genetic risk would potentially improve the efficiency of screening programmes and reduce their adverse consequences," wrote the authors.

Personalised screening offers the potential for costs savings since the cost of the genetic test for risk profiling would be offset by savings on repeat screening and the diagnostic work-up of false positives. Additional benefits would be reduction in the anxiety and inconvenience associated with having the test, and the potential to reduce harms associated with over diagnosis and treatment.

There are ethical and legal issues, the authors added, associated with genetic testing and risk prediction that would need to be addressed before personalised programmes could be implemented.

Commenting on breast cancer, first author Nora Pashayan, said, "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."

Reference

N Pashayan, SW Duffy, S Chowdhury et al. Polygenic susceptibility to prostate and breast cancer: implications for personalised screening British Journal of Cancer (2011) Doi:10.1038/bjc.2011.118