Population-based breast cancer screening not necessarily best for poorer countries

2 Mar 2011

There is increasing pressure from national and international advocacy groups on low-income and middle-income countries (LMICs) to implement population-based mammography screening. But according to an article in The Lancet Oncology, this "one-size-fits-all" approach although proven to be effective in high-income countries would be impractical in most LMCs and an ineffective use of limited health-care resources. A better solution might be to raise awareness and encourage more women with breast symptoms to seek and receive timely treatment.

Globally, breast cancer is the most common female cancer accounting for an estimated 1.4 million cases each year, with more than half of the 400 000 breast-cancer deaths occurring in LMICs. Breast-cancer screening programmes are regularly used in high-income countries where the incidence of breast cancer is highest. However, the value and practicality of such screening programmes in LMICs is less clear. Women in LMICs have a lower risk of breast cancer but tend to be diagnosed at a later stage when curative treatments are less likely to work.

Because rates of breast cancer are generally lower in LMICs, screening programmes aimed at early detection in women without symptoms would have a lower yield and substantially more women would have to be screened to find a case of breast cancer, explains Joe Harford from The National Cancer Institute, Bethesda, USA.

Indeed, he adds, for screening to be effective a high level of compliance is necessary, not only with initial screening but also with treatment in those found to have breast cancer.

The WHO suggests that participation of at least 70% is needed for screening to substantially reduce the number of deaths. But evidence from LMICs suggests this might be difficult. For example, a screening trial involving clinical breast exam in the Philippines was stopped because of the reluctance of women to participate in follow-up and obtain a definitive diagnosis and treatment. Additionally, in the first attempt at screening mammography in Egypt, 2.1% of women were recalled, but more than half were lost to follow up.

In many LMICs the cost of setting up and running screening programmes is high compared with total health spending. A recent analysis concluded that breast screening in India is not cost effective because of the lower incidence and therefore lower yield from screening, and the lack of health-care resources in a country where total health spending per capita is about the same cost as a single mammogram screen in the USA.

Studies of breast-cancer screening in LMICs also suggest that organised screening of women without symptoms might be impractical: "Cultural and economic barriers to participation are one issue, but the magnitude of effort required to screen a large population is another", says Harford. For example, to screen the projected target population of women aged 40–69 years in Egypt in 2025 (an estimated 24 million women) would need a 250-fold increase in government-funded mammography screening capacity.

He adds: "It is difficult to envision that the already stretched Egyptian health-care system could increase from 200 mammograms per day to 50 000 mammograms and 5000 follow-up procedures per day, as well as state-of-the-art treatment, to reduce breast-cancer mortality by around 30% as in high-income countries."

So is there an alternative solution? According to Harford, a more effective approach might be to: "Shift the focus from large asymptomatic populations—who make up most of the participants in a screening programme in LMICs, and most of whom will never have breast cancer—to the much smaller populations of women with breast symptoms."

He points out that key to this approach is the need for more evidence-based research into why women with breast symptoms delay

seeking care and the barriers within health-care systems that prevent earlier diagnosis.

"Raising breast awareness is a laudable goal and one that should be aggressively pursued by advocacy groups and health-care systems in LMICs, without necessarily seeking population-based mammographic screening", concludes Harford.

Source: Lancet Oncology