Trending Science: Cancer screening benefits are overstated, claim experts
The analysis concludes that although there may be fewer deaths from the specific type of cancer for which screening takes place, screening has little impact on the overall mortality rate. The researchers, led by Dr Vinay Prasad at the Oregon Health and Science University, Portland, have thus argued that the success of screening should be measured against the total number of deaths, rather than just deaths from a specific type of cancer, in order to gain a better understanding of the impact of screening programmes. Using the example of prostate cancer, the researchers claim that positive screening results often turn out to be false alarms, leading patients to undergo unnecessary treatment that can have damaging psychological and medical consequences. For example they argue that the one million men annually diagnosed with prostate cancer, and who undergo a biopsy, are more likely to suffer a heart attack, take their own lives in the first year after diagnosis, or die from treatment complications. Summarising the results of the study, Dr Prasad stated: ‘It is clearly the case that some deaths unrelated to cancer are due to screening.’ Moving forward, Dr Prasad and his team recommend that larger population studies should be conducted to ascertain for certain if cancer screening truly does save lives, and that millions of people would need to be involved in one study in order to collect the most accurate findings. Such a study would be better suited to measuring all deaths, rather than just being narrowed down to cancer-specific ones. The research team has though conceded that current public perceptions of cancer screening, coupled with weak political support and high costs, are major hurdles in developing the framework required to undertake such a study. In the meantime, Dr Prasad and his colleagues argue that patients need to be better-informed of the potential risks to screening and should be empowered to make an informed decision on whether the benefits of screening outweigh the potential negative consequences. However, not all of Dr Prasad’s recommendations have been fully endorsed. Gerd Gigerenzer of the Max Planck Institute for Human Development in Berlin, who contributed an accompanying editorial in the BMJ wrote: ‘Rather than pouring resources into ‘megatrials’ with a small chance of detecting a minimal overall mortality reduction, at the additional cost of harming large numbers of patients, we should invest in transparent information in the first place… it is time to change communication about cancer from dodgy persuasion into something straightforward.’
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