Research News

Mammography screening reduces breast cancer deaths in Ireland, study finds

BMJ 2017; 359 doi: (Published 29 December 2017) Cite this as: BMJ 2017;359:j5932

Re The Science of Screening

This Irish study shows a positive result from mammography screening - a reduction in deaths of 9%. Good screening news also comes from a USA lung cancer screening study. 1 A high positive yield in a lung cancer study was due to a focused screening policy. Instead of using the standard screening protocol the authors used a risk weighted screening protocol. The result was a significantly more positive percentage of scans and more deaths prevented.

Screening is an activity that has tremendous health, psychological and financial implications. The vested interest in the screening industry - be it for breast cancer, or lung cancer. or cancer of the prostate, or genetic testing to mention a few - is enormous. Is there a bell curve or screening equation or NICE guideline to control and quantify the quality of safe screening? There is no gold standard for safe high quality and optimum yield screening. Not all screening is the same undoubtedly, but there should be enough in common to formulate a reliable risk-benefit equation. The lung cancer study may be instructive in this regard because it screened only those most likely to have the disease. People should not be routinely screened without achieving a moderate to high cut-off score on a reliable risk checklist. The Checklist Manifesto revolutionised surgery. 2 There is a yawning need for such a checklist in the world (or is it a science yet?) of screening.

Breast cancer screening has spawned an industry of websites, merchandise, and traumatised women (and men). It has been of service to those whose lives were saved through early detection. Is it not time to further risk stratify women for breast screening beginning with those with strong family histories and those of whatever age who were exposed to extraneous female hormones ( oral contraceptives, HRT)? 3 The information is available to risk stratify and doctors have a duty of care to only screen those who have a significant risk.

1. The Effect of Risk-Based Versus U.S. Preventive Services Task Force Eligibility Criteria, 2005–2015
Li C. Cheung, PhD; Hormuzd A. Katki, PhD; Anil K. Chaturvedi, PhD; Ahmedin Jemal, PhD; Christine D. Berg, MD
Ann Intern Med. 2018. DOI: 10.7326/M17-2067 Internal Medicine.

Background: The U.S. Preventive Services Task Force (USPSTF) recommends annual low-dose computed tomography (CT) lung cancer screening for persons aged 55 to 80 years who currently smoke or quit within the past 15 years and have at least a 30–pack-year history of cigarette smoking. The number of U.S. persons meeting USPSTF criteria for CT screening sharply decreased between 2010 and 2015). However, these criteria may exclude smokers at high risk for lung cancer who would have been selected for CT screening by individual risk calculators that more specifically account for demographic, clinical, and smoking characteristics. Risk based screening increases the number of people screened and preventable deaths. Risk based screening in 2015 would have reduced the number of deaths by 5,000 compared to USPSTF screening criteria.
2. Atul Gawande. The Checklist Manifesto. Henry Holt and Co. 2009.
3. Morch L S et al. Contemporary Hormonal Contraception and the Risk of Breast Cancer. N Engl J Med 2017; 377:2228-2239.

Competing interests: No competing interests

03 January 2018
Eugene G Breen
Dublin 7