Research into whether breast cancer might be caused by a virus has begun, just as international research reveals a six-month treatment of breast cancer with the drug Herceptin is not as effective as a full-year treatment.

University of Canterbury researchers will be looking further into previous research which has shown that breast cancer could be associated with a common virus in New Zealand.

Professor Ann Richardson said identifying an infectious cause for breast cancer could lead to preventing a significant proportion of breast cancer.

One prevention could be an immunisation in early childhood.


About 2700 women are diagnosed with breast cancer each year, and over 600 women die from it each year, making it the second most common cause of cancer death after lung cancer.

The researchers will also look at whether bowel cancer could be influenced by dietary changes and whether people with head and neck cancer in Canterbury have access to appropriate support services.

Meanwhile, international research has revealed that women with breast cancer who take the drug Herceptin for only six months are at a higher risk of dying or having their cancer return than those who take the drug for a year.

Results into a French study which looked at the benefits of Herceptin over differing periods of time was presented this week in Vienna.

The study of nearly 3400 women found women who received six months of Herceptin had a 28 per cent higher risk of dying or having their cancer return compared to women who took the drug for a year.

Another study into the drug, also presented this week, found there was no difference between a one-year course and a two-year course of the drug.

Herceptin is used on the 20 to 25 per cent of woman whose tumours over express the HER-2 protein, which make the disease more aggressive.

The drug company behind Herceptin, Roche, said it welcomed the results of the studies.

Roche Products New Zealand general manager Stuart Knight said cancer treatment needed to be based on an awareness of all the scientific data.

The results showed that woman should take Herceptin for one year, he said.

A full 12-month treatment of Herceptin was fully funded by the Government in 2008.

Prior to that government drug-buying agency, Pharmac, chose to fund only nine weeks of the treatment, saying there was no added health benefits and the money would be better spent in other places.

In the 2008 election National promised that if it was elected it would fund the drug for 12 months.

Neither of the two studies looked at a nine-week treatment.

October is Breast Cancer Action Month.