New Zealand's largest private health insurer is under fire for not approving the latest breast cancer screening technology - which researchers say can help detect the disease 40 per cent earlier than a conventional mammogram.

Digital tomosynthesis creates clearer, more detailed 3D images of breast tissue than a standard 2D mammogram, uncovering cancers at an earlier stage and increasing the odds of survival and recovery. Many private health insurers in New Zealand already recognise the evidence behind tomosynthesis and include it in their policies, including Accuro, Sovereign and nib.

However, Southern Cross, which describes itself as "New Zealand's largest private healthcare organisation" has not approved tomosynthesis - despite private clinics lobbying them for months.

Dubbed a "new dimension" in the fight against breast cancer, the pioneering technology has become widespread over the last five years, including around three years of availability through private clinics in this country.

Costing around $280 - about $100 more than a digital mammogram - Research conducted by Sweden's Lund University in May 2015, concluded "tomosynthesis detects 40 per cent more breast cancers than traditional mammography."

Three clinics in Auckland offer tomosynthesis, one of which, Ascot Radiology, volunteers its frustration at Southern Cross on its website.

"Currently Southern Cross Health Insurance will not reimburse any part of breast imaging that includes tomosynthesis. We understand that this discrepancy in insurer reimbursement is very frustrating for women and we at Ascot Radiology remain in talks with Southern Cross," Ascot Radiology's website states.

Co-founder and managing director of Auckland Breast Centre and Focus Radiotherapy, breast cancer surgeon Dr Erica Whineray Kelly, says she is also irritated by Southern Cross' position and the situation is "completely unacceptable" for Kiwi women.

"We got it [tomosynthesis] January two years ago, we were the first to get it in Auckland and it is excellent," Kelly said. "We get so many small cancers now. We love it.

"It's reducing the amount of ultrasounds we do because we get good images of the breast, it's reducing the number of unnecessary biopsies because we're able to see whether something is benign and we're detecting more cancers.

"They [Southern Cross] have been really difficult with us. They won't allow patients to pay a top-up for tomosynthesis. They won't do any refund for the mammogram if they know a patient has had tomosynthesis, which I think is completely unacceptable."

Going above and beyond the Hippocratic Oath, Kelly has resorted to secretly giving Southern Cross clients free tomosynthesis because she believes they deserve it.

"We haven't told Southern Cross this because we want the flat fee for the mammogram, but we basically provide tomosynthesis for free in our clinic because we don't want people to not get the best technology we can offer.

"We're not getting money for that, but there's no way we're saying 'you're Southern Cross, you're getting that one'."
When contacted by the Herald on Sunday, Southern Cross admitted the technology is an improvement and a policy change has been "recommended" for the middle of next year.

"In May Southern Cross Health Society completed a clinical assessment of digital breast tomosynthesis," Rebecca Ogilvie, Southern Cross network manager, said.

"The clinical assessment found that digital breast tomosynthesis was superior when used in conjunction with a traditional mammogram - ie that digital breast tomosynthesis can aid the diagnosis of patients who have shown abnormalities during a mammogram.

"The overall recommendation from the assessment was that the Health Society formally add cover for diagnostic digital breast tomosynthesis as part of our annual benefit review process in mid-2017.

"When any new technology or treatment is added to the list of benefits under our policies, it usually means a new cost to be borne by members' premiums, which is why we carefully assess the cost and benefits of dozens of new technologies every year - and only provide cover for those that are clinically proven, effective and efficient."

New Zealand Breast Cancer Foundation research analyst Adele Gautier says Kiwis who are able to afford private health care should take advantage of the best technology on offer and the foundation is surprised Southern Cross is yet to accept tomosynthesis.

"Maybe a year ago it wouldn't have surprised us because the jury is still out to some extent. But there are studies that do indicate a very good result for tomosynthesis. We would expect any insurer to be keeping on top of the research, going with it and adopting new technologies," Gautier said.

"If you're in the public screening programme, you don't have a choice and it will be a long time before we see tomosynthesis in public programmes because of the additional overheads. It takes radiologists more time.

"If you're fortunate enough to have private insurance then why wouldn't you go for something that can find more breast cancers?"

The Ministry of Health said it is assessing the use of tomosynthesis, is monitoring research - including the Lund University study - and "a pilot has been performed at one provider, and a review of the required changes in quality control procedures is currently under way."

The Ministry said financial modelling to make tomosynthesis a standard service has not been done.