The results on the efficacy of breast cancer screening vary substantially between studies, and the ongoing, at times aggressive, screening debate does not seem to move the field forward. What we need instead, is an open and calm discussion on the methods used in the various studies, and how these methods affect the results. Perhaps we should also acknowledge that both sides in the debate have a conflict of interest, says Giske Ursin, MD, PhD, Director of the Cancer Registry of Norway, in a commentary in the Open Access Journal BioMed Central 12.12.2012.
When appointing members of the Independent UK Panel on Breast Cancer Screening, a panel that recently reviewed existing data on benefits and harms of screening, only scientists that had never before published studies on screening, were selected. This was done to ensure a conclusion as independent as possible on a topic that has become strongly debated, and at times even politicized.
The Director of the Cancer Registry of Norway, Dr. Ursin, has discussed challenges related to the ongoing screening debate in Norway and internationally in a commentary published in the December issue of the Open Access Journal BioMed Central. She argues that none of the participants can claim to have more noble motives or are more neutral than others.
- When will we realize that everyone involved in this debate has conflicts of interest?, asks Dr. Ursin.
As Director of the Cancer Registry of Norway, Dr. Ursin is also responsible for the nationwide Norwegian Breast Cancer Screening Programme that targets all women aged 50 – 69. Hence, she is right in the middle of a scientific debate about how much early diagnosis and treatment reduces breast cancer mortality, and to what cost for the participating women.
- It is vital that we are able to discuss the methods being used in various studies in a calm and open minded way, Dr. Ursin says.
Both Norwegian and international screening researchers use different methods and presumptions in their studies. This leads to large variations in the results. Some methodological approaches are acknowledged in medicine as having much less error than others. Still, some researchers choose methods that are not well suited and have serious weaknesses.
-Researchers should not choose a quick and dirty solution that we know will yield wrong or misleading results, but that will lead to sensational headlines in the media. At the same time we have to acknowledge that there are problems with the better methods as well. It is important that we are honest about the limitations, weaknesses and uncertainties related to the various methods we use, Dr. Ursin explains.
Giske Ursin wants to open a serious debate about the different methods and assumptions that are the basis for outcome estimates in mammographic screening. But, we cannot forget what we already know about statistical and epidemiological methods when we discuss mammographic screening, she points out.
- The same principles apply as in medicine in general, says Dr. Ursin.