Breast and Prostate Cancer Screenings Have Similar Potential for OverDiagnosis

MedicalResearch.com Interview with:
Karsten Juhl Jørgensen, MD, Dr. MedSci
The Nordic Cochrane Centre
Rigshospitalet, Copenhagen 

MedicalResearch.com: What is the background for this study? What are the main findings?

Response: Our systematic Cochrane review of the original randomised breast screening trials showed substantial conflict between their estimates of the benefit. Some trials showed a large benefit, others none or a small benefit. This difference was related to the design of the trials.

The most optimistic trials were those with suboptimal randomisation.

The main findings of our current study support those of the most rigorously performed randomised trials: breast screening does not fulfill its fundamental premise, which is to reduce the occurrence of late stage disease. This means a mortality reduction is unlikely and that use of less invasive surgery due to breast screening is also unlikely.

However, we did find very substantial increases in early stage breast cancer, which persisted over our 17 year observation period. This means that breast screening likely leads to substantial overdiagnosis of breast cancers that would otherwise not have caused health problems during a woman’s lifetime. We estimate that 1 in 3 breast cancers detected in a screened population is likely overdiagnosed.

MedicalResearch.com: What should readers take away from your report?

Response: Breast screening has similar problems to prostate cancer screening. The benefit is small at best and the harms substantial. Women should seek information about benefits and harms from independent sources and decide for themselves whether screening is right for them. This is a value judgement with no single “correct” answer that suits all women. Policymakers should consider if breast screening is a good use of resources.

MedicalResearch.com: What recommendations do you have for future research as a result of this study?

Response: There is a need for a much better understanding of the biology of breast cancer, which likely represent a spectrum of diseases rather than a single entity. 

MedicalResearch.com: Is there anything else you would like to add?

Response: When we remove polyps after colorectal cancer screening, we can see the incidence of invasive cancer go down. We have been removing DCIS for decades, with no impact on rates of invasive breast cancer. We can also see that removing early stage colorectal cancers leads to fewer late stage tumors. Our study shows that breast cancer has a fundamentally different biology that does not lend itself to screening.

Disclosures: I have no financial or personal interest in either supporting or ending any type of cancer screening, including breast cancer screening. I am a doctor and researcher at the main public Danish university hospital.

MedicalResearch.com: Thank you for your contribution to the MedicalResearch.com community.

Citation:

Jørgensen KJ, Gøtzsche PC, Kalager M, Zahl P. Breast Cancer Screening in Denmark: A Cohort Study of Tumor Size and Overdiagnosis. Ann Intern Med. [Epub ahead of print 10 January 2017] doi: 10.7326/M16-0270

Note: Content is Not intended as medical advice. Please consult your health care provider regarding your specific medical condition and questions.

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