Dense breast tissue linked to missed cancers and delayed diagnoses in Ireland

Around 43% of women undergoing mammograms in Ireland have dense breasts, a condition that reduces the contrast between healthy tissue and tumours on imaging, often hiding cancers. Professor Zoe Winters explains that this can lead to later-stage diagnoses and larger tumours, with a 2022 study indicating that as many as 50% of cancers in extremely dense breasts are missed. Advocates such as Siobhán Freeney, who discovered a 7 cm tumour after a clear scan, and Evan Holton, whose proactive ultrasound uncovered two cancers, are campaigning for mandatory density reporting.

The BeingDense campaign has petitioned the National Screening Advisory Committee, and a Hiqa review slated for the end of 2027 will assess extending BreastCheck eligibility and adding standardised density notifications. The Department of Health and the Marie Keating Foundation have expressed support for clearer, evidence-based guidance, emphasizing that early awareness could mean less invasive treatment for many women.