Whether breast cancer screening saves lives or leads to harm has been the topic of intense debate in recent years, and this controversy has been highlighted in a collection of articles published recently in BMC Medicine. As outlined in our previous blog, in an opinion article, Donella Puliti and Marco Zappa advocate case-control and incidence-based mortality (IBM) study designs to assess whether screening is effective. The authors conclude, based on the results of these studies, that screening does reduce breast cancer-related deaths and therefore the benefits outweigh the risks.
However, Philippe Autier and Mathieu Boniol from The International Prevention Research Institute present an alternative view. In their opinion article, the authors describe the limitations of case-control and IBM studies for measuring breast screening success, and recommend that caution should be applied when interpreting the results of these studies. Autier and Boniol suggest that temporal trends should be analyzed to assess whether screening is effective, given the problems with the other study designs. Nonetheless, this recommendation is also controversial, as there are many limitations associated with temporal trend analyses, which are discussed by Puliti and Zappa.
Recently, Cancer Research UK set up the Independent UK Panel on Breast Cancer Screening to analyze the benefits and harms of screening, and to ensure an objective assessment, none of the panel members had previously published on breast cancer. The investigation concluded that overall, breast screening saves lives, but at the cost of overdiagnosis.
These findings, together with the controversy surrounding different study designs, are discussed in a commentary published in BMC Medicine by Giske Ursin from the Cancer Registry of Norway. Ursin emphasizes that while all study designs have limitations, it is important to work together to address the issues analytically. As highlighted by the panel investigation, women should be given all the information in a transparent way, so that they can make an informed choice about whether to undergo screening.
Looking forward, Ursin describes a number of new diagnostic methods and prognostic markers that are currently being developed. When validated in the clinic they could be used alongside screening to assess a woman’s risk of dying from breast cancer and guide clinical decision making. Application of these techniques should help to avoid false positive results and unnecessary treatment for slow-growing tumors. Therefore, when more accurate diagnostic information is available in the future, the choice about whether to undergo screening should be less controversial.