Higher mastectomy rate for women in NZ

By MARTIN JOHNSTON

New Zealand breast cancer patients have a far higher rate of full mastectomies than British women.

The rate of armpit surgery is also much higher in New Zealand than recommended for women diagnosed with disease one level short of invasive cancer.

The figures were presented at a national breast cancer conference in Auckland yesterday.

A study of 1309 women aged 50 to 64 in the national breast screening programme found that the full-mastectomy rate was about 50 per cent higher than Britain for those with the smallest tumours.

Separate research on 1700 of the around 2400 greater Auckland women diagnosed with breast cancer since June 2000 confirms New Zealand's higher full-mastectomy rate than many overseas hospitals.

One of the researchers in that study, Dr Vernon Harvey, head of medical oncology at Auckland Hospital, said the reasons could include patient choice based on a family history of the disease; living a long way from a treatment centre; and delays in starting radiotherapy.

"Ten per cent live more than 50km from the oncology department. If you have a partial mastectomy, you have to come for radiation therapy 20 times, so some people choose a [full] mastectomy rather than coming back for radiation therapy."

The conference convener, Auckland breast surgeon John Collins, said the number of patients diagnosed with early, non-spreading cancer who received armpit surgery was too high, but the reasons were unclear. Many of these patients had a large area of so-called ductal carcinoma in situ (DCIS), he said.

Many surgeons preferred to operate on the armpit when removing tissue from the associated breast, rather than doing a second operation if it turned out to be a spreading cancer.

The Auckland database also shows breast cancers are being detected while much smaller now than in the 1980s.

NZ statistics

* Incidence expected to rise, because of ageing population, delayed child-bearing and women having fewer babies - factors which increase breast-cancer risk.

* Otago University says death rate falling, but still 28 per cent higher than Australia's.

* Health Ministry says 80 per cent of patients alive five years after treatment, possibly the same as in Australia.

* Screening programme detected 1309 cases of invasive cancer in the three years to December 2001.

* Of patients with the smallest tumours (under 15mm in diameter) around 30 per cent had a full mastectomy, compared with about 20 per cent in the British screening programme.

* Of 354 patients diagnosed with early, non-spreading cancer, 22 per cent had armpit surgery - in addition to breast surgery - compared with guidelines recommending a maximum of 5 per cent.

* Average wait for radiotherapy patients to start the therapy was 91 days from surgery, compared with 56 in the guidelines.