Author Interviews, Breast Cancer, Mammograms / 06.05.2016
Overdiagnosis of Breast Cancer Through Mammograms Complicated by Lack of Understanding of Tumor Progression
MedicalResearch.com Interview with:
Ragnhild Falk PhD
Oslo Centre for Biostatistics and Epidemiology
Research Support Services
Oslo University Hospital and
Solveig Hofvind PhD
Department of Screening Cancer Registry of Norway
and Oslo and Akershus University College of Applied Sciences
Oslo, Norway
MedicalResearch.com: What is the background for this study? What are the main findings?
Response: The issue of overdiagnosis has been heavily debated, and a variety of results have been presented. However, the exact proportion of overdiagnosis is unknown as one do not know what would have happen in the absent of screening.
We have split the proportion of overdiagnosis into two parts based on the time at which the death occur; scenario 1 as the proportion of women diagnosed with a screen-detected breast cancer and who died within the lead-time period, and scenario 2 as women detected with slow growing tumors that never would have caused any harm during the women’s life if she had not attended screening.
In principle, all screening programs will detect breast cancer among women who die of other causes in the near future since there exist competing risk of death among women targeted by screening. Although the all-cause mortality rates are low, it is inevitable.
We wanted to focus on the first scenario and estimated the number of women diagnosed with screen detected breast cancer who died within the estimated lead-time period caused by screening. We estimated his proportion to be less than 4 percent of all screen-detected cases in the given England & Wales and the Norwegian setting.
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