Nikki Slade Robinson while undergoing chemotherapy. Photo / Supplied
Nikki Slade Robinson while undergoing chemotherapy. Photo / Supplied
Nikki Slade Robinson's health was in the clear at the end of 2018 after a negative mammogram - until it wasn't.
Her whole world turned upside down with the discovery of a lump only a few months later.
A diagnosis of breast cancer followed, along with chemotherapy, radiation and adouble mastectomy - basically a year she would like to flush "down the toilet".
Although she is on the way to recovery, the discovery that her dense breast tissue may have meant her cancer was not detected in the mammogram has left her with questions.
That's why she is welcoming a study investigating dense breast tissue and whether it increases the risk of being diagnosed with breast cancer between mammogram screenings.
"I just felt like the world's been turned upside down.
"Last year was full of chemo and radiotherapy and I would basically like to flush that year down the toilet."
Slade Robinson, who lives in Ōpōtiki,
believes the more women who know about the density of their breast tissue, the better.
"We're just not being told, if we don't know that we're in that group, we can't take the right actions to keep ourselves safe.
"That's all I'm asking really, is for them to change their policy so they record the information and tell the women in that category."
Nikki Slade Robinson with the book titled Hedgehog Heart that she illustrated through radiotherapy treatment. Photo / Supplied
In New Zealand, it is not recorded if women have high density when they have their mammogram, unlike other parts of the world where a standardised breast density grading system has been developed and extensively studied.
The Ministry of Health states breast density can be measured on mammography, however, there are difficulties in grading breast density and a lack of evidence that extra monitoring of women with dense breasts will reduce deaths from breast cancer.
"For women with dense breasts who otherwise have an average risk of breast cancer, there is insufficient evidence to recommend additional imaging such as ultrasound or MRI."
There are also harms of extra imaging, such as causing anxiety, unnecessary needle biopsies, over-diagnosis and cost, the ministry said.
"Overall the harms are likely to outweigh the benefits. These women can continue to participate in the BreastScreen Aotearoa programme by regular mammography every two years."
However, Dr Monica Saini, breast radiologist for the Hutt Valley District Health Board, disputed this, stating there were over 300 international studies overseas - Canada, United Kingdom, United States - that indicated two things:
Higher breast density could mask cancer and the biology of dense tissue was the same biology that could develop breast cancer.
"In my opinion, the correct answer is there is plenty of literature to show that breast density does both
hide cancer and cause its own inherent risk factor for cancer.
"I don't want to hear the argument that we don't have local data, so if that is the issue, I will get local data so we know what the numbers are."
Dr Monica Saini, lead radiologist at Hutt Valley District Health Board. Photo / Supplied
Breast tissue is composed as fibroglandular tissue and fatty tissue. Dense breasts have more of this fibrous tissue supportive tissue and non-dense breasts have more fatty tissue.
While it's not clear why some women have dense breast tissue and others don't, it is understood it is a mix of genetics, environment, and lifestyle factors.
If your breasts are dense it can also be difficult to interpret your mammogram. Saini describes it as "searching for a snowball in a snowstorm" because both the dense tissue and cancer appear white on the scan.
She said density could not be determined by breast size or by physical exam. The only way to know was by a mammogram.
Saini's study will factor in ethnicity, age and family history.
"We actually don't know, in New Zealand, how many women are affected and who is at greater risk.
"We need to know what is the most effective way to improve the ability to find invasive cancer in at-risk women."
Mammograms are done with a machine like this. Photo / File
Saini said the ultimate goal of the study was to prevent interval cancers, those diagnosed between screenings, from happening.
"By understanding how breast density and other risk factors relate to interval cancers, we can improve screening in order to catch cancer earlier and reduce deaths."
Breast Cancer Foundation chief executive Evangelia Henderson said Saini had identified a huge and important gap in their knowledge.
"We need to know which women are more likely to develop interval cancers, so we can improve our screening programme.
"Early detection is the best defence against breast cancer, and our hope is that Monica's study will take us one step closer towards zero deaths from breast cancer becoming a reality."
The study will involve looking at roughly 200 cases of women aged 45-69 in the greater Wellington region who were diagnosed with an interval cancer between January 2014 and December 2020, compared to a control group of around 200 women who were screened at the same time and didn't develop cancer.
