Our breast cancer screening programme scores highly on its services but using new technologies could make it even better, say some experts. By Kirsty Cameron
Breast cancer has scarred Melanie Webber's family, physically and emotionally. The Wellington resident has lost her grandmother and a cousin to the disease; her mother has also had it.
Last May, shortly after starting her new role as president of the Post-Primary Teachers' Association, Webber underwent a double mastectomy after surgery failed to clear her breasts of ductal carcinoma in situ (DCIS, the first stage of breast cancer).
With her family history and her own "very complex breasts full of all sorts of nonsense", the 46-year-old had opted to have annual mammograms for the previous eight years, often undergoing the trifecta of screening and diagnostic tests: mammogram X-ray, ultrasounds and breast MRI.
As well as her inherited risk, Webber was also aware of another key factor in breast cancer detection: that she has dense breast tissue. This has been proven to be a heightened breast cancer risk, though one that advances in detection technologies are able to help. But at present there is no requirement to inform a woman in the New Zealand screening programme, BreastScreen Aotearoa, of her breast density or record it on her report.
About 767,000 women aged 45-69 are eligible for free mammograms biennially under the screening programme. After two years of lockdowns reducing services, about 65 per cent of all those eligible are now in the programme, down from about 70 per cent at the end of 2019. Māori and Pasifika participation rates are lower.
A woman presenting for a mammogram will have four X-rays taken of her breast: two views each side. If this screening, and comparison with any earlier mammograms, shows anything the radiologists want to examine further, she will be recalled. This second session will probably involve another mammogram and an ultrasound, which can pick up tumours that may not have been seen clearly on the mammogram. It may also clarify whether an abnormality is a benign lump or something warranting further investigation. If a cancer is suspected, a biopsy is likely.
In recent years, another diagnostic tool has become available – mammography tomosynthesis X-ray. Tomosynthesis gives multiple, 3D views of the breast and can increase the detection of cancers by up to 30 per cent.
In private practice, tomosynthesis is generally offered to asymptomatic women. In public screening, it's more often employed for recalls or a second assessment. In the words of Wellington breast radiologist Monica Saini, "2D mammograms are the front and back cover of the book, whereas 3D mammograms are every page in between."
In Saini's Wellington private practice, Breast Institute New Zealand, she has another new technology to use that is particularly pertinent for women who are at higher breast cancer risk based on family history, personal history or breast density. In contrast-enhanced spectral mammography (CESM or CEM), dye – the same as used for CAT scans – is injected, and it will make a cancer instantly visible to the radiologist. It's particularly useful for mapping disease ahead of surgery. The technology, a software bolt-on to existing mammography X-ray hardware, gives her four crystal clear images.
Saini's is the only private practice here using CEM. It's also being trialled in the public system at the Hutt Valley District Health Board, where Saini also works as a radiologist. The technology was able to be added to the DHB's eight-year-old mammography machines, and although in place for not quite a year, the results are encouraging.
"I'd been following CEM for four years until I started doing it myself," says Saini. "And I've just been blown away. It's easy, it's cheap. And I love the idea of four pictures rather than 2000 MRI images."
At Hutt Valley, CEM is offered in place of a breast MRI to women with a new diagnosis of breast cancer and considered at elevated risk of additional disease. It takes about seven minutes to execute, says Saini, compared with a breast MRI's 30 minutes, and costs about $590, whereas a private breast MRI can cost two to three times as much. Another plus is that it's part of the existing mammography set-up, whereas MRI machines are in demand by multiple specialities.
US-trained Saini is on the medical advisory board of the Breast Cancer Foundation of New Zealand and she's a passionate advocate for better targeted screening for women with dense breast tissue.
"When you look internationally at all the data – 300-plus articles, 30 years of research – [breast density] is the most common risk factor in women around the world," she says. "And to put that in perspective, more than 90 per cent of the breast cancers we are diagnosing, around the world, these women have no family history. I think that's relevant because we always talk about family history as being a big deal but if most of the breast cancers we are diagnosing have no family history, then what was the risk factor? Density is not all of it, but it's a huge chunk."
And unless a woman has had earlier problems, like Mel Webber, many will hit BreastScreen Aotearoa at 45 unaware of their breast density. The screening report will not advise them, either, as it does not allow the radiologist to make comments, other than noting the mammogram is normal or abnormal, where the abnormality is, and whether further imaging is required.
Sally Urry is the clinical director of BreastScreen Counties Manukau and a senior breast radiologist at Ascot Radiology in Auckland. She is keen to see the findings of Hutt Valley's CEM trial, which will be submitted to the Ministry of Health's national screening unit.
There is also optimism for Urry in a long-overdue IT upgrade for the national screening programme, which has run on essentially the same software since its launch in late 1998. One of the key changes the upgrade will bring, says a Ministry of Health spokesperson, is to better equip the programme to reach the 271,000 women who are eligible to access breast screening but are not currently being screened. The existing system operates as an "opt-in" model. Under the new system, women will be invited to enrol and will be screened unless they opt out.
With 30 years' practice in her clinical speciality, Urry has seen enormous changes in all areas of radiology. "Mammography – 2D mammography or 3D mammography – is the gold standard in the diagnosis of breast cancer," she says.
She believes the screening service and its public or private diagnostic follow-up are "extremely solid".
New Zealand has a very high level of qualification of radiologists and equipment, she says. "And regardless of the equipment we're using, the most important thing for us to do is to screen women regularly – every two years in the screening programme, and if they've got extremely dense breasts, every year. In our diagnostic service in South Auckland, we have a whole body of women we screen annually – there's family history, risk factors. They alternate between BreastScreen and the diagnostic service."
But for women under 45, dense breasts are not a risk factor for publicly funded screening, and that does concern Urry, particularly for those outside main centres.
"What we are slightly frustrated about is that we have mobile vans that go to hard-to-reach areas, and there are women in those areas who have high risk – either family history, personal history, or who have been shown to have extremely dense breasts – who are not able to have a mammogram on the mobile because there isn't the funding to do that.
"We believe that if you're taking a mobile to Tokomaru Bay or to Gore, why wouldn't you?"
Saini acknowledges the cost of a deeper-reaching screening programme, both at a financial and resourcing level. She is well aware that specialist breast radiologists are in short supply internationally. But as a start, she would like data on density to be collected, so scale can be measured.
"If we were to do something different from the 2D mammogram we do every two years, that would take a significant amount of resource, so we should be mindful of that. However, my argument is that first off, we should just collect the data.
"We should know how many women in New Zealand would be affected. And there are different approaches to what we do about women who might be in that highest-density category."
Those approaches could include offering women in the highest categories follow-up testing. Published, peer-reviewed research shows it catches more cancer, sooner. And there's a huge social-cost gain to doing that.
"The benefit of diagnosing a cancer at stage one, which has a 92 per cent cure rate, versus stage three, where we're talking disfiguring surgery, chemotherapy, radiotherapy, not being able to work, not being able to take care of their family – and women are always taking care of other people, whether it's ageing parents or children – that's a huge impact on society," Saini says.
"People talk about financially, how do we support a second test or an additional test? But they don't look at the cost for all these women, who are probably in the workforce, to no longer be caring for people in their lives … [or] the cost of treatment. You've got to look at all of those things together."
Saini urges being open with women. "We need to be transparent, and we need to be forthright."
Once that density data is available – Saini would like to see it collected as part of the BreastScreen software upgrade – it would show who is at highest risk and how it affects women of different ethnicities, including Māori and Pasifika. "Maybe our approach needs to be two or three tiers, and we could do that in a more cost-effective way."
Also working in the capital is another leading advocate for better understanding of breast density. Ralph Highnam is an Oxford PhD in medical physics and artificial intelligence, and chief executive of Volpara Health, the tech company he founded in 2009. Volpara developed AI software to read breast density. (Saini worked for the company from 2017, stepping down as a non-executive director last August to open her private practice.)
The software, which works with both 2D and 3D mammography, gives the radiologist a detailed analysis of a woman's breast density. It is used in 39 countries, and the company estimates at least one of its software products is used in the screening of a third of women screened for breast cancer in the US annually.
In Australia, the company has a five-year software access contract with BreastScreen Queensland and the technology will be used in a state-wide breast density research project in South Australia.
"We're very motivated by making an impact, and by science," says Highnam. "The science is just overwhelming that women should be told density."
Highnam was drawn to using his AI powers for health research through a mixture of personal motivation and professional fulfilment. "The prospect of doing AI for autonomous cars and that kind of stuff bored me to tears," he says.
It was a discussion with another AI academic, Sir Mike Brady, that led ultimately to Volpara. Brady's mother-in-law had died of breast cancer, and Brady posited that while breast cancer screening was proven to save lives, there had to be a way to improve detection rates with AI. Highnam had also lost family members and friends to the disease.
He would like action on the density message. "The Ministry of Health has got a unique opportunity because Volpara is here and people like Monica are here. They just need to get a bit more visionary, not wait for Australia or Europe and start getting ahead of the game. We're here, let's do it. They've got a world-class opportunity, [but] I don't see the vision in the ministry to actually to do that."
In a statement for the Listener, the ministry says there is no agreement internationally about the best way to measure breast density, or whether additional imaging should be offered for women with dense breasts. It says its policy is in line with other population-based screening programmes in the UK, Europe and parts of Australia.
"BreastScreen Aotearoa provides a safe and high-quality service, which is based upon a proven method of finding breast cancers early," it says. It also notes that screening mammograms in women aged 45-69 can find 80-90 per cent of cancers.
In its published statement on density, BreastScreen says it has reviewed the evidence and that for women with dense breasts who otherwise have an average risk of cancer, "there is insufficient evidence to recommend additional imaging (such as ultrasound or MRI). The harms of extra imaging, such as causing anxiety, unnecessary needle biopsies, over-diagnosis and cost, are likely to outweigh the benefits."
For Sally Urry, reinforcing the message about regular breast screening is critical. "The most important thing is awareness. If you have a screening mammogram regularly for 10 years, you reduce your chance of dying of breast cancer by over 30 per cent, because what we're monitoring in the screening programme is change. We're looking for the evidence of breast cancer, but we're also looking for change since the previous mammogram."
Melanie Webber's vigilance was critical. With her history, which includes non-cancerous fibroadenomas, Webber was straight on to her breast specialist when she found a lump in her right breast in October 2020. It turned out to be a cyst, but an ultrasound discovered a more suspicious mass in her other breast.
Initially a partial mastectomy was done, but it turned out she had cancerous cells inside a milk duct. A second surgery to remove the cells was not fully successful, so Webber underwent a third round of surgery: a bilateral mastectomy and reconstruction. More abnormal cells were discovered in her right breast, which had not been detected by ultrasound or MRI.
Weeks after her first surgeries – all within the private system – she turned 46 and received an invitation to make her first BreastScreen Aotearoa appointment. She should have got it a year earlier, at her 45th birthday in April 2020, but was one of the many women affected when screening services were suspended during the first nationwide lockdown.
After two years of further Covid disruptions, the ministry estimates there is a backlog of 50,000 women to be screened. The Breast Cancer Foundation says this could mean there are around 133 women unaware they have the disease.
Even without the year-long lag, the public programme would have come at what may have been a critically late stage for Webber, had she not already been under private care.
"I have become obsessive about telling friends about [density] – I know that my breast density made it harder to see the cancer. Most women aren't even aware if they have dense breasts." She chooses to be optimistic that advances in knowledge, education and technology will mean the next generation won't have to experience what she has been through.
“I’m really hopeful that my nieces won’t have to deal with this kind of shit. Because it’s very, very dull.”
