For most women, finding time for a mammogram and dealing with the low-grade stress of the appointment – between the discomfort and a natural alertness to the process –is plenty to be getting on with.

A normal result brings welcome relief and, mentally at least, the job is firmly ticked off the list.

But what if that reassuring result doesn’t tell the whole story? Cancer can be harder to detect in dense breasts through a mammogram, while density itself is also associated with an increased risk of developing the disease.

Yet many women are never told they have dense breasts in the first place.

Understanding breast density

For Dubliner Evan Holton (51), understanding her breast density prompted her to seek an ultrasound despite a clear mammogram in January and no symptoms. In April, she was diagnosed with stage-one invasive lobular breast cancer.

Evan began paying for mammograms in her mid-40s, before becoming eligible for nationwide free mammograms through BreastCheck at 50.

Her mother had undergone surgery to remove a radial scar at 50, so she was taking a proactive approach to her own breast health.

At an earlier appointment, a clinician told Evan she had very dense breasts, but offered little explanation.

“She didn’t tell me what that meant. She didn’t tell me what to do. She didn’t tell me anything, but the way she had said it felt loaded.”

Evan decided to research the issue herself.

“What I knew was that my mammogram wasn’t the full picture and I was at risk.”

Over the years, she asked about additional screening, including an MRI. When her January 2026 mammogram came back clear, she was still uneasy. “I just felt I should get it checked.”

During an unrelated GP appointment in April, she requested an ultrasound. Initially, she says, she was refused because she had no symptoms, but she persisted and secured a referral.

At St Vincent’s Private Hospital on 28 April, Evan was asked whether she had found a lump.

“No. I have dense breasts. And I’m just here for an ultrasound as a form of extra screening.”

During the examination, an area of concern was identified and a biopsy followed.

Two weeks later, Evan found herself sitting opposite a breast surgeon and cancer nurse, being told she had invasive lobular carcinoma.

“My tumour measured just 1cm but it had not spread to my lymph nodes. I had a lumpectomy in September, and was able to keep my own breast and nipple.

“It also meant I did not need chemotherapy.”

Considering Evan had no symptoms and had received a clear mammogram just months earlier, the significance of having pursued an ultrasound is enormous.

She believes understanding her breast density made a profound difference to her diagnosis and treatment.

We’re not asking for automatic additional scans for every woman. We simply want women to know whether they have dense breasts so they can discuss their individual risks and options with their doctor

Siobhán Freeney, chairperson of Lobular Breast Cancer Ireland, had a vastly different experience.

In June 2015, Siobhán attended BreastCheck and received a clear mammogram result. Six months later, she was diagnosed with stage three breast cancer. Her tumour measured 7cm.

She underwent chemotherapy, a mastectomy, lymph-node surgery and radiotherapy, followed by a second mastectomy in 2020. She also had to retire from her career earlier than planned.

“I thought, how long has this been there?” she recalls.

Diagnosis and screening

Siobhán began researching breast density and sought answers about why her cancer had not appeared on the mammogram. In January 2016, she says, she was told she did not have dense breasts. Yet reports she later obtained through a Freedom of Information request described her breasts as “dense and glandular”.

It was not until March 2020, more than four years after her diagnosis, that the HSE acknowledged she had very dense breasts and that her tumour had been obscured on the earlier mammogram.

She believes knowing her density earlier, and being able to discuss further screening, could have changed her experience enormously and likely reduced the treatment she needed.

“It’s not about my personal story now because it’s bigger than that,” she says. “It’s about lots and lots of personal stories.”

Siobhán’s search for answers became a campaign. She co-hosted a public breast-density symposium in 2019 and established Lobular Ireland to support people affected by invasive lobular breast cancer.

On 13 October, she and fellow campaigners returned to Leinster House, calling for women to be routinely informed of their breast density following mammograms, whether through BreastCheck or privately.

The meeting brought home the human cost. Hannah Fox, who has stage-four breast cancer, spoke powerfully, alongside her husband Andy. Siobhán says their account visibly affected the politicians listening.

“You could see it on their faces,” she recalls. The campaigners say they have cross-party backing. Fianna Fáil and Fine Gael TDs attended, while Sinn Féin’s Mary Lou McDonald and David Cullinane and Labour leader Ivana Bacik have pledged support.

“I just feel that there isn’t room for politics in this,” Siobhán says. “We’re not asking for automatic additional scans for every woman. We simply want women to know whether they have dense breasts so they can discuss their individual risks and options with their doctor.”

In the United States, breast density notification became a federal requirement in September 2024. Currently, Ireland’s BreastCheck programme does not routinely assess or report density. HIQA has been examining the evidence around density notification and possible changes to screening.

Early detection

In a poignant way, Evan has become a symbol of what earlier detection might make possible. During a discussion involving women diagnosed at different stages, one described her as their ‘prescription for change’.

Evan’s stage one diagnosis stands in stark contrast to Siobhán’s experience and to Hannah’s advanced cancer. The campaigners hope that giving women information about breast density will help more of them investigate their risks and, where appropriate, seek further screening.

For Siobhán, the determination to keep pushing has survived years of frustration.

“There are times when you think no one is listening, but there is somebody listening. There’s always somebody listening,” she says.