Targeted screening may reduce overdiagnosis of breast cancer

July 6 (UPI) -- A "risk-based" breast screening program could improve the lives of women who are screened for breast cancer by reducing overdiagnosis and saving resources.

A study published Friday in JAMA Oncology shows that a screening initiative that did not include low risk women would improve the quality of life following screening, reduce overdiagnosis and save resources, while maintaining the benefits of screening.

It's known as the economic evaluation and simulation modeling study, and was funded by Cancer Research UK and led by the UCL Department for Applied Health Research with support from the University of Cambridge.

"Breast screening has both benefits and harms: It can reduce death from breast cancer in some women while others may have unnecessary diagnosis and treatment of breast cancer," Dr. Nora Pashayan, lead author of the study, said in a press release. "Offering screening according to women's risk level could improve the efficiency of the screening program and reduce its harms."

Britain's NHS Breast Screening Program recommends women between age 50 and 69 for a digital mammogram every three years. Previous studies have shown, however, that breast cancer risk varies significantly among women due to individual genetic, lifestyle and reproductive factors.

The researchers simulated three hypothetical cohorts of women who were 50 years old and free of cancer, including follow-ups over 35 years. Each group had 364,5000 women, which was the 2009 population of 50-year-old women in England and Wales.

The first group received no screening. The second received a mammogram at age 50 and then every three years after. The third group underwent a risk estimation and only those with a risk score greater than a low threshold of risk were offered screening every three years until age 69.

For the model, the researchers considered predicted rates of age-specific breast cancer, breast cancer-specific mortality in screened and unscreened populations, and an overdiagnosis estimate developed by the UK Independent Panel on Breast Cancer Screening.

The researchers also modeled cost effectiveness of age-based and risk-based approaches to screening, along with no screening, by using NHS costs for the screening program and costs of breast cancer treatment.

The benefit-to-harm balance was measured as the ratio of overdiagnosis to breast cancer deaths prevented. The researchers simulated 100 different risk-based screening scenarios.

They found that in a risk-targeted screening, if screening is not offered to women at the lowest 30 percent of the risk distribution, there could be 27 percent fewer overdiagnoses, three percent fewer breast cancer deaths avoided and cost the NHS about $26,000 less.

When they increased the threshold, so that screening was targeted to 30 percent of the highest risk women, there could be 71 percent fewer overdiagnoses, 10 percent less breast cancer deaths avoided and lower the cost to NHS by about $713,000.

The researchers acknowledged challenges to this approach, including defining low-risk women and making screening based on risk acceptable to the public, health professionals and regulators. More targeted screening would reduce the detriment caused by over diagnosis and increase the chances of early diagnosis for those at risk, they said.

"We need to change the model of delivery of breast screening and recognize that women are individuals with different risks and lifestyles," said Professor Fiona Gilbert, a co-author of the study from the University of Cambridge. "They should be offered screening tailored to their own profile."