Mammography screening: A major issue in medicine

Area of Science:

• Oncology
• Public Health
• Epidemiology

Background:

• Breast cancer mortality is declining globally, with ongoing debate on mammography screening's role.
• Screening aims to reduce advanced cancers, while therapies reduce cancer fatality.
• Overdiagnosis, the detection of non-progressive cancers, is a significant issue in mammography screening.

Purpose of the Study:

• To evaluate the effectiveness of mammography screening in reducing breast cancer mortality.
• To assess the impact of mammography screening on the incidence of advanced breast cancers.
• To analyze the contribution of mammography screening versus improved therapies in mortality reduction.

Main Methods:

• Analysis of epidemiological data on advanced cancer incidence and mortality rates in populations with varying mammography screening levels.
• Reappraisal of mammography screening trials, including Swedish trials and the UK Age Trial.
• Evaluation of statistical models used to estimate screening's contribution to mortality reduction.
• Comparison of different breast imaging modalities based on detection rates and overdiagnosis potential.

Main Results:

• Epidemiological data show no or modest declines in advanced cancer incidence in well-screened populations.
• Breast cancer mortality reductions are similar in areas with high and low mammography screening penetration.
• Overdiagnosis is common, affecting 20-50% of screen-detected cancers, leading to overtreatment.
• Reappraisals suggest mammography trials may overestimate mortality reduction due to statistical methods and underreporting.
• Improved therapies since 1985 have significantly reduced breast cancer mortality, even for advanced stages.

Conclusions:

• Mammography screening's contribution to breast cancer mortality decline appears marginal compared to advancements in patient management and therapies.
• Overdiagnosis and overtreatment pose significant harms, challenging the benefit-harm balance of mammography screening.
• Current evidence suggests a need for new breast screening methods and risk-based screening strategies, particularly for high-risk women.