From the Guidelines
Breast cancer is most likely to be visible on multiple mammographic views rather than a single view, especially for small lesions. This approach is supported by the European guidelines for quality assurance in breast cancer screening and diagnosis, which recommend that two views of each breast should be carried out in a screening programme as this has been demonstrated scientifically to increase the number of screen-detected cancers and reduce the number of women recalled for assessment 1. The use of multiple views, such as craniocaudal and mediolateral oblique views, helps to confirm that suspicious findings are real and not just a result of superimposition of normal tissues or technical artifacts.
When a suspicious finding appears on multiple views, it confirms that the abnormality is real rather than a superimposition of normal tissues or a technical artifact. Small breast cancers in particular may be subtle and can be missed if only one view is obtained. Additional specialized views such as spot compression, magnification, or tomosynthesis (3D mammography) may be necessary to better characterize suspicious findings.
The benefits of using multiple views include:
- Increased detection sensitivity due to the three-dimensional nature of breast tissue
- Improved ability to triangulate findings across different views to determine the true location and characteristics of potential malignancies
- Reduced number of women recalled for assessment due to false positives
- Increased number of screen-detected cancers, applying equally to prevalent and incident rounds, as demonstrated by the European guidelines 1.
Overall, the use of multiple mammographic views is a crucial aspect of breast cancer screening and diagnosis, particularly for small lesions, and is supported by the most recent and highest quality evidence 1.
From the Research
Visibility of Breast Cancer on Mammographic Views
- The visibility of breast cancer on mammographic views can be affected by the type of view used, with some studies suggesting that multiple views can improve detection accuracy 2, 3.
- A study found that in 92% of cases, candidate mass detections by Computer-Aided Detection (CAD) included the cancer regions in both mediolateral oblique (MLO) and craniocaudal (CC) views, and a correct link between the true positive regions in both views could be established in 82% of cases 2.
- Another study compared the sensitivity of a CAD system for depicting breast cancer in three digital mammographic views (craniocaudal, mediolateral oblique, and mediolateral) and found that sensitivity increased when multiple views were combined 3.
Small Lesions and Mammographic Views
- For small lesions, the use of multiple mammographic views can be particularly important, as they can be more difficult to detect on a single view 4, 3.
- A study found that texture features from the MLO and CC views were less strongly correlated for calcification lesions than for mass lesions, and that the inclusion of texture features from multiple mammographic views in a CADx algorithm may impact the accuracy of diagnosis of calcification lesions and benign lesions 4.
- However, another study found that one view is sufficient to assess association and predict future risk of breast cancer over a 5 or 10-year interval, suggesting that multiple views may not always be necessary for risk assessment 5.
Comparison of Mammographic Views
- The craniocaudal view has been found to be more sensitive than the mediolateral oblique view for detecting microcalcifications, but the difference in sensitivity between the two views was not significant for masses 3.
- A study found that the association between percent volumetric density from CC, MLO, and the average between the two, retained essentially the same association with breast cancer risk, and that the 5- and 10-year risk prediction also showed similar prediction accuracy 5.