2004-03-17
MACRO helps researchers highlight reduction in breast cancer recurrence from new drug sequence
Early results of a major new trial, co-ordinated by Cancer Research UK funded groups and published in the New England Journal of Medicine on 10th March 2004, have shown that taking a breast cancer drug called exemestane after tamoxifen can substantially reduce the chance of recurrence.
Currently, most breast cancer patients receive a five-year course of tamoxifen following surgery to help prevent their cancer from coming back. But, the international study involving over 4,700 post-menopausal women across 37 countries, including the UK, found that switching to exemestane after two to three years of tamoxifen reduces the risk of breast cancer returning by a third (32 per cent) when compared with women who remained on tamoxifen for a full five years.
Researchers from the International Collaborative Cancer Group at Imperial College London and The Institute of Cancer Research led the study, which was funded by Pfizer.
The data was collected using InferMed’s electronic data collection system MACRO.
Cancer Research UK experts say that while the results are promising, it is essential to find out any long-term effects of the drug sequence before any firm recommendations can be made.
Lead author Professor Charles Coombes, Director of the Cancer Research UK Laboratories at Imperial College London, Hammersmith and Charing Cross Hospitals, says: "While tamoxifen can prevent recurrence in most patients there are still many who relapse within five years of diagnosis.
"This happens because breast cancer can become resistant to the drug. So we thought that switching from tamoxifen to an aromatase inhibitor, in this case exemestane, during a five-year course of hormone treatment could be beneficial.
The trial recruited 4,742 post-menopausal women between 1998 and 2003 who had undergone surgery for breast cancer and taken tamoxifen for two to three years. Half of the group continued taking tamoxifen while the other half switched to exemestane to complete a total of five years of hormone treatment.
Patients were followed up for an average of two and a half years after they were randomly assigned to take exemestane or continue on tamoxifen.
Researchers found disease-free survival three years after randomisation was 92 per cent in patients who switched to exemestane compared with 87 per cent in patients who continued on tamoxifen.
Fellow author Judith Bliss, Director of the Cancer Research UK Clinical Trials and Statistics Unit at The Institute of Cancer Research and joint chair of the MACRO Academic Research Focus Group, says: "Though recurrence of breast cancer in women taking tamoxifen was already low, our results show that switching to exemestane can reduce that number by a about a third.
"This study represents a real example of clinicians and scientists from around the world working together, overcoming differences in local health care practices, to conduct the trial as quickly as possible and get the information out there for future patients.
