Original Title: Dépistage du cancer du sein par tomosynthèse mammaire

Authors' objectives: Early detection of breast cancer is the only recognized effective secondary prevention to reduce breast cancer mortality in women over 50 years old. The Programme québécois de dépistage du cancer du sein (PQDCS) has been recommending Quebec women aged 50 to 74 to undergo bilateral screening mammography every two years. Tomosynthesis, an imaging technique that can be combined with mammography (3D + 2D) or synthetic 2D projection (3D + 2Ds), enables consecutive images of the breast to be taken, limiting the overlap of breast tissue on the images. In 2019, the Institut national d'excellence en santé et en services sociaux (INESSS) published some recommendations on the use of tomosynthesis (3D ± 2D or 2Ds) for breast cancer screening in Quebec [INESSS, 2019]. This report concluded that several uncertainties remained regarding the added value associated with replacing mammography with tomosynthesis (3D ± 2D or 2Ds) for breast cancer screening, possible adverse effects, and the transferability of performance results from selected studies to the Quebec screening context. In light of recent publications on the subject, and sustained interest in this technology by healthcare professionals, the INESSS was given the mandate to re-evaluate the performance and safety of tomosynthesis, and to formulate recommendations for its use in breast cancer screening in Quebec.

Authors' results and conclusions: RESULTS (#1 QUEBEC PRACTICE): The PQDCS has been recommending that women aged 50 to 74 to undergo screening mammography every two years. Since the program's inception in 1998, 1,464,703 women have participated, for a total of 5,915,724 screening mammograms, resulting in the detection of 34,729 breast cancers. • Canada has one of the highest recall rates for women screened for breast cancer in the world (7.8% for subsequent mammograms in 2017). Since 2017, Quebec has been the province with the highest recall rate in the country (9.7% for subsequent mammograms in 2017) without a corresponding increase in the breast cancer detection rate. (#2 LEVEL OF SCIENTIFIC EVIDENCE ASSESSMENT): Some methodological limitations were reported among the studies reviewed (uncertain transferability of results, heterogeneous follow-up times, presence of confounding factors and insufficient statistical power for certain evaluation parameters) and must be considered when interpreting the results. • The level of evidence associated with assessing tomosynthesis (3D ± 2D or 2Ds) performance and safety in comparison with mammography (2D) was mostly considered moderate to high. (#3 PERFORMANCE AND SAFETY): The performance of breast cancer screening with tomosynthesis (3D ± 2D or 2Ds) is improved compared to the use of mammography (2D) for several parameters: – specificity (1.0%); – breast cancer detection rate (0.5 to 3.0 per 1,000 women); – invasive cancers detection rate (0.7 to 2.5 per 1,000 women); – recall rate (-3.7 to 0.5%); – positive predictive value of recall (PPV1) (1.77 to 9%). The safety of tomosynthesis (3D ± 2D or 2Ds) is similar to that of mammography (2D), with the exception of the radiation dose, which is higher when tomosynthesis is used in combination with mammography (3D + 2D). (#4 ORGANIZATIONAL ISSUES): The Mammography Accreditation Program (MAP) standard of the Canadian Association of Radiologists (CAR) allows accreditation of mammography and tomosynthesis (3D ± 2D or 2Ds), as required by screening programs. • Tomosynthesis (3D ± 2D or 2Ds) increases data volume and reading time for radiologists, due to the acquisition of multiple images. According to the clinicians consulted, the potential clinical benefits of tomosynthesis on recall rates, biopsy rates, and stress levels induced in women could outweigh the increased workload for radiologists. However, there is no data to support this hypothesis. (#5 EFFICIENCY AND BUDGETARY IMPACT): Analysis of the economic assessments found in the literature suggests that tomosynthesis (3D + 2D or 2Ds) could be cost-effective compared to mammography (2D). However, the efficiency results were sensitive to variations in the main inputs to the models used, notably the costs of the procedure and its effect on recall rates. • In the absence of data on the current use of tomosynthesis and its total cost, it is difficult to estimate the budgetary impact of implementing this screening modality.

Authors' recommendations: INESSS considers that mammography (2D) remains the standard for breast cancer screening under the PQDCS. Although tomosynthesis can be considered as an alternative to screening mammography, there is currently insufficient evidence to recommend a province-wide transition to the use of tomosynthesis. If tomosynthesis is used for screening, it should be in combination with synthetic 2D projection (3D + 2Ds) because of the lower radiation dose compared with tomosynthesis combined with mammography (3D + 2D). As a complement to this position, INESSS emphasizes that designated screening centres wishing to use tomosynthesis combined with synthetic 2D projection (3D + 2Ds) for breast cancer screening should do so with the following considerations : R1. Standards for the use of tomosynthesis combined with synthetic 2D projection (3D + 2Ds) must remain the same as for the use of mammography (2D); R2. The use of the tomosynthesis modality should be mandatorily mentioned in screening reports, and local performance data should be collected and analyzed regularly. OTHER CONSIDERATIONS REGARDING BREAST CANCER SCREENING IN QUEBEC: For several years, Quebec has had a high recall rate (PQDCS data), higher than other Canadian provinces. In view of this problem, INESSS suggests the implementation of awareness-raising and mitigation measures, such as a feedback process, to improve screening performance in the various designated centers. • The presence of a RAMQ fee-for-service billing code specific to the use of tomosynthesis in breast cancer screening could help harmonize billing practices and, consequently, assess current practice, frame its use, report PQDCS performance data according to imaging modality, analyze associated costs, and prevent inequities.

Authors' methods: A systematic review of data from the literature was conducted to compare the performance and safety of various tomosynthesis modalities (3D ± 2D or 2Ds) and of mammography (2D). The selected literature included randomized clinical trials (RCTs) and meta-analyses. Consultations with clinicians were also conducted.

Project Status: Completed

URL for project: https://www.inesss.qc.ca/publications/repertoire-des-publications/publication/depistage-du-cancer-du-sein-par-tomosynthese-mammaire.html

Year Published: 2024

URL for published report: https://www.inesss.qc.ca/publications/repertoire-des-publications/publication/depistage-du-cancer-du-sein-par-tomosynthese-mammaire.html

English language abstract: An English language summary is available

Publication Type: Full HTA

Country: Canada

Province: Quebec

Organisation Name: Institut national d'excellence en sante et en services sociaux

Contact Address: L'Institut national d'excellence en sante et en services sociaux (INESSS) , 2021, avenue Union, bureau 10.083, Montreal, Quebec, Canada, H3A 2S9;Tel: 1+514-873-2563, Fax: 1+514-873-1369

Contact Name: demande@inesss.qc.ca

Contact Email: demande@inesss.qc.ca

Copyright: L'Institut national d'excellence en sante et en services sociaux (INESSS)