Mass screening for breast cancer hardly the best or only way to reduce mortality

The sponsored feature ('Should we have population based breast screening in Hong Kong? The Community needs evidence', August 16) incorrectly credits universal mammography for cancer detection as 'the only modality' for reducing mortality.

It implies cancer deaths occur because Hong Kong lacks population-wide screening, ignoring the large-scale harm caused by indiscriminate mass population screening, including very high levels of false positive tests and lack of effectiveness in reducing mortality in those with the disease.

Trials in large populations, on which current screening is based, were mostly negative and possible signals of benefit only detected by pooling data from several countries, indicating the overall benefit of a positive test to a woman is below 50:50. In Europe, declining trends in breast cancer mortality are similar between countries with long and short screening histories.

The current debate overseas about the poor performance of screening as a prevention tool emphasises that these problems are greatly amplified in low-incidence regions like Hong Kong.

Yes, urgent action and more applied research are required, but so is greater balance. The feature overlooked recent published analyses in Hong Kong, based on the best evidence available, which unambiguously demonstrate these serious limitations of indiscriminate screening lead to inappropriate and unethical use of health dollars that could help reduce breast cancer mortality in other ways. Ensuring that women promptly present self-detected symptoms, which in Hong Kong are seen in 63 per cent of breast cancer cases, and receive high-quality, timely treatment makes major (and much understated) contributions to mortality reduction. Changing patient awareness and consultation practices could significantly improve breast cancer outcomes.

We should focus research and investment in these areas, together with the best treatment facilities and techniques, and we must improve case finding in women with quantified high-risk profiles, an approach quite different from unspecified mass screening. Protecting against breast cancer is vital, but uncritical media advertorials that avoid the fundamental scientific and technical difficulties of applying tests to an entire population mislead public understanding. Screening and treatment policies should be reviewed in the most appropriate forums, such as the Cancer Expert Working Group.