Breast compression in BreastScreen Norway

Status: Completed

Main findings: We observed large variation in the use of breast compression between breast centres in BreastScreen Norway, and also within the breast centers. Women screened using digital breast tomosynthesis received slightly lower compression force compared to women screened using standard digital mammography. Furthermore, increasing breast compression was observed when the same woman attended consecutive screening examinations.

The doctoral project also found that the radiation dose increased by quartiles of compression force and compressed breast thickness, where the highest values ​​of compression force and compressed breast thickness had the highest radiation dose.

Based on this project, Waade and colleagues concluded that there is a need for increased awareness to the practice of breast compression in mammographic screening. Today’s guidelines for breast compression should be revised with a aim of establishing evidence-based guidelines. The guidelines should be developed as a partnership between radiographers, radiologists, medical physicists and women in the target group of the screening program.

Background

Breast cancer is the most common cancer among women worldwide, and in Norway. Screening for breast cancer has been implemented to reduce the mortality of the disease. In Norway, BreastScreen Norway (Mammografiprogrammet) invites all women aged 50-69 years biennially to screening for breast cancer.

The screening examination consists of two-view (craniocaudal (CC)) and mediolateral oblique (MLO)) x-ray examination of the breast, using digital mammography equipment.

This project focuses on the radiographic issues of mammographic screening. Radiographers play an essential role in mammographic screening, and about 97% of the women who participate in the breast cancer screening program in Norway every year see a radiographer, and only the radiographer, during their participation in the screening program.

Radiographers are responsible for providing radiologists with high quality images, which is important in order to identify small abnormalities in the breast. Therefore, breast compression is used during the examination to reduce the thickness of the breast thickness, as this is supposed to increase image quality and reduce radiation dose. However, the breast compression may be uncomfortable or painful for the woman attending screening, and the experiences of the women may affect future screening attendance.

There are currently no evidence-based guidelines regarding optimal breast compression to use. The European guidelines for quality assurance in breast cancer screening and diagnosis states; “the breast should be properly compressed, but no more than is necessary to achieve a good image quality”. Further, national guidelines for quality assurance in mammography in European countries often have a large range of accepted compression force values, typically within the range 10-20 kg.

The lack of evidence-based and objective recommendations for breast compression might lead to variations in use of compression between radiographers and breast centres, which could affect image quality, radiation dose and the experiences of the women.

Aim

The studies included in this PhD-project aims to investigate how breast compression is performed in clinical practice of breast cancer screening today.

The results may raise awareness to breast compression and serve as a first step towards creating evidence-based guidelines for breast compression.

Research questions

1)      What compression forces are being used between and within breast centres in BreastScreen Norway today? Published.

2)      What is the relationship between compression force, compressed breast thickness and radiation dose? Published.

3)      What breast compressions are being used on the same woman attending consecutive screening examinations? Published.

4)      Are there any differences in use of breast compression with digital mammography and digital breast tomosynthesis? Published.

Publications

Paper I: Waade GG, Moshina N, Sebuødegård S, Hogg P, & Hofvind, S. (2017). Compression forces used in the Norwegian Breast Cancer Screening Program. Br J Radiol, 90 (1071), 20160770.

Paper II: Waade GG, Sanderud A, & Hofvind S. (2017). Compression force and radiation dose in the Norwegian Breast Cancer Screening Program. Eur J Radiol, 88, 41-46.

Paper III: Waade GG, Sebuodegard S, Hogg P, Hofvind S. (2018). Breast compression across consecutive examinations among females participating in BreastScreen Norway. Br J Radiol,  91(1090), 20180209.

Paper IV: Breast compression parameters among women screened with standard digital mammography and digital breast tomosynthesis in a randomized controlled trial. Waade GG, Holen Å, Sebuødegård S, Aase H, Pedersen K, Hanestad B, Hofvind S. Acta Radiol. 2019 Jul 25