Screening: is breast cancer overdiagnosed?

Area of Science:

• Oncology
• Public Health
• Radiology

Background:

• Mammography screening is a widely used tool for early breast cancer detection.
• Concerns exist regarding the potential for overdiagnosis, where cancers are detected that would not have caused harm or death.

Purpose of the Study:

• To quantify the extent of breast cancer overdiagnosis in publicly organized mammography screening programs.
• To assess the implications of overdiagnosis for clinical practice and public health.

Main Methods:

• Analysis of data from five international mammography screening programs.
• Quantification of overdiagnosis rates for all breast cancers and invasive breast cancers separately.

Main Results:

• An estimated 52% of all detected breast cancers (including carcinoma in situ) represent overdiagnosis.
• Overdiagnosis of invasive breast cancer was estimated at 35%.

Conclusions:

• Mammography screening programs are associated with substantial overdiagnosis of breast cancer.
• Findings suggest a need to re-evaluate screening protocols and patient counseling to mitigate the harms of overdiagnosis.