Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Late treatment with letrozole can reduce breast cancer recurrence risk

11.03.2008
Therapy beginning long after stopping tamoxifen still offers preventive benefits

Treatment with the aromatase inhibitor letrozole (Femara) can reduce the risk of breast cancer recurrence even when initiated one to seven years after a course of tamoxifen therapy.

The results of a study involving women originally in the placebo arm of an international trial of letrozole will appear in the Journal of Clinical Oncology and are receiving early online release. Among those who chose to begin letrozole treatment after the initial trial was halted, the risk that their cancer would recur was cut in half compared with those who never received letrozole. In addition, the risk of metastasis was 60 percent lower with letrozole, and the chance that a new tumor would develop in the unaffected breast dropped more than 80 percent.

“It appears that estrogen-sensitive tumors remain hormone dependent and that patients’ survival can be improved with careful use of aromatase inhibitors, even many years after completing tamoxifen treatment,” says Paul E. Goss, MD, PhD, director of Breast Cancer Research at Massachusetts General Hospital Cancer Center, who led both the current study and the earlier investigation, called the MA.17 trial. “These results can be put into practice right away to improve the outlook for women treated for receptor-positive breast cancer.”

Letrozole is one of a class of drugs called aromatase inhibitors that suppress the production of estrogen, which stimulates the growth of breast tumors expressing the estrogen receptor. The most widely used estrogen-blocking drug is tamoxifen, but the benefits of tamoxifen treatment drop significantly after five years, while the drugs’ side effects continue.

The original MA.17 trial, conducted through the National Cancer Institute of Canada, was designed to test whether letrozole could reduce tumor recurrence and increase survival in breast cancer patients who had completed five years of tamoxifen treatment. The study was halted in October 2003 – a year earlier than planned – when interim data analysis showed that tumors of women taking letrozole were significantly less likely to recur. The final analysis of MA.17 data, published in the September 7, 2005 Journal of the National Cancer Institute, confirmed that women taking letrozole had significantly better disease-free survival than those taking a placebo.

Since women who received letrozole in the MA.17 trial began taking the drug within a few months of stopping tamoxifen treatment, letrozole’s current approval restricts the initiation of therapy to the first three months after tamoxifen discontinuation. However, participants in the placebo arm of the MA.17 trial were offered the opportunity to begin letrozole treatment when that trial was halted, which gave investigators the opportunity to determine whether those women could also benefit from the drug.

The current study analyzes data on more than 1,500 women from the placebo group who chose to take letrozole and about 800 who chose no further treatment. Almost three years after the MA.17 trial was halted and letrozole offered, those who began letrozole therapy had only a 2 percent risk of tumor recurrence, compared with almost 5 percent in those choosing no treatment. The risk of death from breast cancer during that period was cut in half in those receiving letrozole. Treatment also reduced the risk of metastasis by 61 percent and appeared to prevent development of a new tumor in the opposite breast by 82 percent.

The research team notes that this study is limited by the fact that participants choose whether to take the drug themselves and were not randomly assigned. While a randomized clinical trial would more conclusively determine the benefit of letrozole treatment for those who have been off tamoxifen for several months or years – or even those who never took the drug – the results of this study can help guide physicians and patients in deciding whether letrozole therapy would be appropriate.

“Every patient who has previously taken tamoxifen should discuss these new results with her oncologist. The risk that hormone-dependent breast cancer will recur continues indefinitely, and our results imply that aromatase inhibition is effective whenever initiated,” says Goss, a professor of Medicine at Harvard Medical School

Stacy Neale | EurekAlert!
Further information:
http://www.mgh.harvard.edu/
http://www.massgeneral.org

More articles from Health and Medicine:

nachricht Cystic fibrosis alters the structure of mucus in airways
28.06.2017 | University of Iowa Health Care

nachricht Mice provide insight into genetics of autism spectrum disorders
28.06.2017 | University of California - Davis

All articles from Health and Medicine >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Can we see monkeys from space? Emerging technologies to map biodiversity

An international team of scientists has proposed a new multi-disciplinary approach in which an array of new technologies will allow us to map biodiversity and the risks that wildlife is facing at the scale of whole landscapes. The findings are published in Nature Ecology and Evolution. This international research is led by the Kunming Institute of Zoology from China, University of East Anglia, University of Leicester and the Leibniz Institute for Zoo and Wildlife Research.

Using a combination of satellite and ground data, the team proposes that it is now possible to map biodiversity with an accuracy that has not been previously...

Im Focus: Climate satellite: Tracking methane with robust laser technology

Heatwaves in the Arctic, longer periods of vegetation in Europe, severe floods in West Africa – starting in 2021, scientists want to explore the emissions of the greenhouse gas methane with the German-French satellite MERLIN. This is made possible by a new robust laser system of the Fraunhofer Institute for Laser Technology ILT in Aachen, which achieves unprecedented measurement accuracy.

Methane is primarily the result of the decomposition of organic matter. The gas has a 25 times greater warming potential than carbon dioxide, but is not as...

Im Focus: How protons move through a fuel cell

Hydrogen is regarded as the energy source of the future: It is produced with solar power and can be used to generate heat and electricity in fuel cells. Empa researchers have now succeeded in decoding the movement of hydrogen ions in crystals – a key step towards more efficient energy conversion in the hydrogen industry of tomorrow.

As charge carriers, electrons and ions play the leading role in electrochemical energy storage devices and converters such as batteries and fuel cells. Proton...

Im Focus: A unique data centre for cosmological simulations

Scientists from the Excellence Cluster Universe at the Ludwig-Maximilians-Universität Munich have establised "Cosmowebportal", a unique data centre for cosmological simulations located at the Leibniz Supercomputing Centre (LRZ) of the Bavarian Academy of Sciences. The complete results of a series of large hydrodynamical cosmological simulations are available, with data volumes typically exceeding several hundred terabytes. Scientists worldwide can interactively explore these complex simulations via a web interface and directly access the results.

With current telescopes, scientists can observe our Universe’s galaxies and galaxy clusters and their distribution along an invisible cosmic web. From the...

Im Focus: Scientists develop molecular thermometer for contactless measurement using infrared light

Temperature measurements possible even on the smallest scale / Molecular ruby for use in material sciences, biology, and medicine

Chemists at Johannes Gutenberg University Mainz (JGU) in cooperation with researchers of the German Federal Institute for Materials Research and Testing (BAM)...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Plants are networkers

19.06.2017 | Event News

Digital Survival Training for Executives

13.06.2017 | Event News

Global Learning Council Summit 2017

13.06.2017 | Event News

 
Latest News

Supersensitive through quantum entanglement

28.06.2017 | Physics and Astronomy

X-ray photoelectron spectroscopy under real ambient pressure conditions

28.06.2017 | Physics and Astronomy

Mice provide insight into genetics of autism spectrum disorders

28.06.2017 | Health and Medicine

VideoLinks
B2B-VideoLinks
More VideoLinks >>>