By JENNY HOPE

Last updated at 12:49 26 September 2007

Women with advanced breast cancer live longer by taking the drug Herceptin even after a relapse, a study reveals.

Those who continue with treatment when the disease has progressed are three times more likely to be alive two years later compared to those who do not.

Overall, three out of four women on continuous Herceptin treatment were still alive after two years, compared to just 24 per cent who came off the drug at an earlier stage.

British experts say the study could have important implications for women starting treatment for breast cancer, as well as for those in whom it has spread.

After a series of high-profile battles by women trying to win NHS funding for Herceptin, which costs around £20,000 for a year's supply, the Government's 'rationing' body NICE extended its use in certain patients from late-stage to early stage cancer last year.

Around a quarter of the 44,000 British women diagnosed with breast cancer each year have the HER2 positive form, which is more aggressive.

The study of those with this aggressive form of cancer released yesterday at the European Cancer Congress in Barcelona is further evidence of Herceptin's remarkable effects.

Specialists believe the drug is the most important development in breast cancer treatment for 25 years.

The data comes from the Hermine trial, an observational study involving 340 women with advanced HER2-positive breast cancer.

The average survival rate for those who continued to take the drug after the disease progressed was 27.8 months, compared to 16.8 months for patients who gave it up.

Dr Murray Brunt, clinical oncologist at the University Hospital of North Staffordshire NHS Trust, said: "This data is very welcome and provides evidence supporting the continuation of Herceptin therapy beyond disease progression for women with this particularly aggressive form of breast cancer.

"It appears that maintaining Herceptin therapy alongside chemotherapy to provide continuous suppression of HER2 may enhance the effectiveness of chemotherapy, and help keep the cancer under control for longer."

Consultant breast surgeon Hugh Bishop, president of the Association of Breast Surgery, said it was vital for all women to be tested for HER2 status when cancer was diagnosed.

"At present, Herceptin is reserved by Government decree for those who have a poorer prognosis of breast cancer, for example where there is local spread to the armpit, along with chemotherapy.

"That message has been accepted by NICE, but what about women who have a better prognosis and don't need chemotherapy?

"Would these women not benefit from Herceptin?

"We need trials, but in the mean time this new data raises the issue of how long should women should be taking it for and the costs involved.

"It seems women could keep taking Herceptin, if they don't experience any heart side effects, throughout progression because it stops the disease accelerating. We've never had drugs like this before."

Herceptin works by binding to the part of the tumour essential for growth, preventing cell division.

This causes the tumour to stop growing or even shrink.