Little breast tumours that seemed cured after surgery are more likely to
come back if they are HER2 positive, US researchers reported yesterday.
They said women who had these types of tumours may need treatment with
drugs such as Genentech's Herceptin, which is notcommon practice overseas.
"Most physicians do not treat these small tumours with Herceptin," Dr Ana Gonzalez-Angula of the MD Anderson Cancer Centre in Houston, Texas, who led the study, said.
After five years, 23 per cent of patients with tiny tumours - 1cm or smaller - whose cancer was HER2 positive had tumours come back after surgery, Gonzalez-Angula told the San Antonio Breast Cancer Conference.
Her team looked at more than 1300 women. Ten per cent had HER2-positive
tumours and they had a much higher likelihood the cancer would come back
than those with other more common tumours.
Different types of tumour each have a different mutation that drives the cancer. Oestrogen-receptor-positive breast tumours are the
easiest to treat.
The women in the study, with an average age of 57, had 2.68 times the risk their cancer would come back after surgery if they had HER2-positive tumours than the other patients, Gonzalez-Angula said.
HER2-positive tumours had been more difficult to treat but Herceptin is a genetically engineered antibody that homes in on that particular mutation.
The New Zealand Government has just funded 12 months of treatment with Herceptin for women with HER2-positive breast cancer. Previously only nine weeks of treatment was funded.
