Benefits and harms of annual, biennial, or triennial breast cancer mammography screening for women at average risk of breast cancer: a systematic review for the European Commission Initiative on Breast Cancer (ECIBC)

• Published in: British journal of cancer Vol. 126; no. 4; pp. 673 - 688
• Main Authors: Canelo-Aybar, Carlos, Posso, Margarita, Montero, Nadia, Solà, Ivan, Saz-Parkinson, Zuleika, Duffy, Stephen W., Follmann, Markus, Gräwingholt, Axel, Giorgi Rossi, Paolo, Alonso-Coello, Pablo
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 09-03-2022; Nature Publishing Group
• Subjects: 692/699/67/1347; 692/700/478/2772; Adult; Age Factors; Age groups; Aged; Biomedical and Life Sciences; Biomedicine; Breast cancer; Breast Neoplasms - diagnostic imaging; Cancer Research; Drug Resistance; Early Detection of Cancer; Epidemiology; Europe - epidemiology; False Positive Reactions; Female; Humans; Mammography; Mammography - adverse effects; Mammography - statistics & numerical data; Middle Aged; Molecular Medicine; Observational Studies as Topic; Oncology; Practice Guidelines as Topic; Risk Assessment; Europe
• ISSN: 0007-0920; 1532-1827
• DOI: 10.1038/s41416-021-01521-8

Background
Although mammography screening is recommended in most European countries, the balance between the benefits and harms of different screening intervals is still a matter of debate. This review informed the European Commission Initiative on Breast Cancer (BC) recommendations.
Methods
We searched PubMed, EMBASE, and the Cochrane Library to identify RCTs, observational or modelling studies, comparing desirable (BC deaths averted, QALYs, BC stage, interval cancer) and undesirable (overdiagnosis, false positive related, radiation related) effects from annual, biennial, or triennial mammography screening in women of average risk for BC. We assessed the certainty of the evidence using the GRADE approach.
Results
We included one RCT, 13 observational, and 11 modelling studies. In women 50–69, annual compared to biennial screening may have small additional benefits but an important increase in false positive results; triennial compared to biennial screening may have smaller benefits while avoiding some harms. In younger women (aged 45–49), annual compared to biennial screening had a smaller gain in benefits and larger harms, showing a less favourable balance in this age group than in women 50–69. In women 70–74, there were fewer additional harms and similar benefits with shorter screening intervals. The overall certainty of the evidence for each of these comparisons was very low.
Conclusions
In women of average BC risk, screening intervals have different trade-offs for each age group. The balance probably favours biennial screening in women 50–69. In younger women, annual screening may have a less favourable balance, while in women aged 70–74 years longer screening intervals may be more favourable.