Use of repeated mammograms to evaluate risk of breast cancer: a systematic review of methods used in the literature

Abstract ObjectiveThis systematic review aimed to assess methods used to relate repeated mammographic images to breast cancer risk, including the time from mammogram to diagnosis of breast cancer, and methods for analysis of data from either one or both breasts (averaged or assessed individually). DesignA systematic review was performed. SettingThe databases including Medline (Ovid) 1946-, Embase.com 1947-, CINAHL Plus 1937-, Scopus 1823-, Cochrane Library (including CENTRAL), and Clinicaltrials.gov were searched through October 2021 to extract published articles in English describing the relationship of change in mammographic features with risk of breast cancer. ParticipantsWomen with mammogram images. Main outcome measureBreast cancer incidence. ResultsTwenty articles were included in the final review. We found that BIRADs and Cumulus were most commonly used for classifying mammographic density and automated assessment was used on more recent digital mammograms. Time between mammograms varied from 1 to median of 4.1 years, and only 9 of the studies used more than 2 mammograms to quantify features. One study used a prediction horizon of 5 and 10 years, one used 5 years only and another 10 years only, while in the others the prediction horizon was not clearly defined with investigators using the next screening mammogram. ConclusionThis review provided an updated overview of the state of the art and revealed research gaps; based on these, we provide recommendations for future studies using repeated measure methods for mammogram images to make the use of accumulating image data. By following these recommendations, we expect to improve risk classification and risk prediction for women to tailor screening and prevention strategies to level of risk. Article summaryStrengths and limitations of the studyTo the best of our knowledge, this is the most recent systematic review on the topic of using multiple mammogram images to define risk of breast cancer.This review was performed strictly following systematic review guidelines including a medical librarian with expertise in searching, multiple independent reviewers involved in study selection and data extraction, and reporting following PRISMA 2020 guidelines.Due to heterogeneity of methods for assessment and classification (categorical and continuous) of mammographic features including breast density and time to breast cancer, we did not perform risk of bias or conduct a meta-analysis.Few studies looked at repeated measures of non-density features.