Screening for breast cancer - a systematic review update to inform the Canadian Task Force on Preventive Health Care guideline

Sep 21, 2026

Systematic review update synthesizing recent evidence on benefits and harms of breast cancer screening in women aged 40 years and older to support an update of the Canadian Task Force on Preventive Health Care guideline. Searches in Ovid MEDLINE, Embase, and Cochrane Central Register were updated to July 8, 2023 with study screening in duplicate and machine learning prioritization. Outcomes included mortality, treatment-related morbidity, and overdiagnosis, with evidence certainty assessed using GRADE.

LanguageEnglish

CategoryResearch & Report

FormatPDF

Pages26

Reading Time1 h 6 min

AccessFree to download

Abstract

Objective

Methods

Results

Bennett et al. Systematic Reviews (2024) 13:304 [https://doi.org/10.1186/s13643-024-02700-3](https://doi.org/10.1186/s13643-024-02700-3) Systematic Reviews SYSTEMATIC REVIEW UPDATE Open Access Screening for breast cancer: a systematic review update to inform the Canadian Task Force on Preventive Health Care guideline Alexandria Bennett 1*† , Nicole Shaver1†, Niyati Vyas1, Faris Almoli1, Robert Pap1, Andrea Douglas2, Taddele Kibret1, Becky Skidmore3, Martin Yaffe4, Anna Wilkinson5, Jean M. Seely6, Julian Little 1 and David Moher7 Abstract Objective This systematic review update synthesized recent evidence on the benefits and harms of breast cancer screening in women aged ≥ 40 years and aims to inform the Canadian Task Force on Preventive Health Care’s (CTFPHC) guideline update. Methods We searched Ovid MEDLINE® ALL, Embase Classic + Embase and Cochrane Central Register of Controlled Trials to update our searches to July 8, 2023. Search results for observational studies were limited to publication dates from 2014 to capture more relevant studies. Screening was performed independently and in duplicate by the review team. To expedite the screening process, machine learning was used to prioritize relevant references. Critical health outcomes, as outlined by the CTFPHC, included breast cancer and all-cause mortality, treatment-related morbidity and overdiagnosis. Randomized controlled trials (RCTs), non/quasi RCTs and observational studies were included. Data extraction and quality assessment were performed by one reviewer and verified by another. Risk of bias was assessed using the Cochrane Risk of Bias 2.0 tool for RCTs and the Joanna Brigg’s Institute (JBI) checklists for non-randomized and observational studies. When deemed appropriate, studies were pooled via random-effects models. The overall certainty of the evidence was assessed following GRADE guidance. Results Three new papers reporting on existing RCT trial data and 26 observational studies were included. No new RCTs were identified in this update. No study reported results by ethnicity, race, proportion of study population with dense breasts, or socioeconomic status. For breast cancer mortality, RCT data from the prior review reported a significant relative reduction in the risk of breast cancer mortality with screening mammography for a general population of 15%(RR 0.85 95% CI 0.78 to 0 . 93) . In this review update, the breast cancer mortality relative risk reduction based on RCT data remained the same, and absolute effects by age decade over 10 years were 0.27 fewer deaths per 1000 in those aged 40 to 49; 0.50 fewer deaths per 1000 in those aged 50 to 59; 0.65 fewer deaths per 1000 in those aged 60 to 69; and 0.92 fewer deaths per 1000 in those aged 70 to 74. For observational data, the relative mortality risk reduction ranged from 29 to 62% . Absolute effects from breast cancer mortality over 10 years ranged from 0.79 to 0.94 fewer deaths per 1000 in those aged 40 †Alexandria Bennett and Nicole Shaver contributed equally to this work. *Correspondence: Alexandria Bennett [d.bennett@uottawa.ca](d.bennett@uottawa.ca) Full list of author information is available at the end of the article © The Author(s) 2024. Open Access This article is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License, which permits any non-commercial use, sharing, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if you modified the licensed material. You do not have permission under this licence to share adapted material derived from this article or parts of it. The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Crea

FAQs

What question does this systematic review update address?

It synthesizes recent evidence on the benefits and harms of breast cancer screening for women aged 40 years and older to inform the CTFPHC guideline update.

How were studies identified and selected in the update?

Searches were updated to July 8, 2023 across Ovid MEDLINE ALL, Embase Classic + Embase, and Cochrane Central Register of Controlled Trials, with duplicate screening and machine learning used to prioritize references.

What did the update find regarding new randomized trials and key outcomes?

Three new papers were included, but no new randomized controlled trials were identified. Results address breast cancer mortality, all-cause mortality, and overdiagnosis, including absolute effects by age decade and invasive cancer outcomes.

Sep 21, 2026

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