Scientists have found a new and simple way to identify breast cancer patients who are likely to respond well to treatment with a common class of chemotherapy drugs, and predict who is unlikely to see any benefit.
The findings presented by researchers at the European Breast Cancer Conference in Spain mean doctors should be able to test patients, tailor treatment to them and avoid giving them toxic drugs that will not help.
By conducting a study called a meta-analysis of four large breast cancer trials including nearly 3,000 patients, the researchers found that an abnormality on chromosome 17, called CEP17, is a "highly significant indicator" that the tumour will respond to chemotherapy drugs called anthracyclines.
Anthracyclines are anti-tumour antibiotics that interfere with enzymes involved in DNA replication. They are widely used against a variety of cancers.
"Our aim was to identify patients for whom anthracyclines provided benefit… and to seek to ensure that future treatment was targeted to this group," John Bartlett of Britain's Edinburgh University, who led the study, said in a statement.
After adjusting for factors relating to the tumour and its treatment, the researchers found that if patients with CEP17 were treated with anthracyclines, they were around two-thirds more likely to survive, and to survive without a recurrence of cancer, than those not treated with anthracyclines.
"This suggests that only those patients with CEP17 tumours should receive anthracyclines," Bartlett said.
The results provide more tools for doctors to make personalised, or tailored, medicine a reality in cancer care. CEP17 is on the same chromosome as other genes known to be involved in breast cancer, such as HER-2, and can be detected with a simple test called fluorescent in situ hybridisation, or Fish, which is carried out routinely in breast cancer patients.
Doctors can already also test for certain genes to tell whether a woman's breast cancer is sensitive to estrogen and likely to benefit from hormone-blocking drugs like tamoxifen. Patients whose breast tumours are HER-2 positive are often given the drug Herceptin, made by Roche Holding, which only works against these kinds of tumours.
Bartlett said the existence of a readily available test for CEP17 meant doctors could immediately start to better tailor chemotherapy to patient needs. He said extra work on CEP17 was needed to see if it could reveal more about breast cancers.
"It [CEP17] works as a biomarker for predicting response to anthracyclines, but we don't know why it works. So our next step is to discover this and to try to make the cancers that don't have the marker behave like the ones that do," he said.
US researchers published a study in January that found that changes in two genes on a small region of chromosome 8q made tumours resistant anthracyclines, but not other types of chemotherapy drug. (Reuters)
Diet trims breast cancer risk
A woman cannot change her family history of breast cancer, but she may be able to trim her chances of getting the disease by eating more vegetables and whole grains and drinking less liquor, according to a new study.
An analysis of 18 published studies involving 400,000 people conducted by Queen's University Belfast in Northern Ireland found there was an 11 per cent lower risk of breast cancer among women in the highest versus lower categories of a prudent diet.
Those consuming larger amounts of spirits had a 21 per cent increased risk of breast cancer, said the analysis published in the American Journal of Clinical Nutrition.
"As the incidence of breast cancer continues to rise, with many of the risk factors for the disease non-modifiable, potentially modifiable risk factors such as diet are of interest," said researcher Dr Sarah Brennan.
But Brennan said these findings had to be interpreted cautiously as there are inherent statistical problems in combining the results of multiple studies, in addition to the limitations of each included study, such as recall bias. She pointed to the need for more carefully designed studies in the future to further examine the diet-breast cancer link.
It is estimated that 120 out of every 100,000 American women are diagnosed with breast cancer each year.