Since dense breasts have more connective tissue than fatty tissue, it can be hard to spot tumours on a mammogram.
"Women with very dense breasts are also four to five times more likely to develop breast cancer than women with less dense breasts," Dr. Greer said. "Because breast density is only identifiable on a mammogram or other imaging modalities, regular screening is imperative."
She noted that not all mammograms are created equal; a recent study found that digital breast tomosynthesis (DBT), or 3D screening mammography, is more efficient than digital (2D) mammograms.