Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


New evidence eases some concerns about bone fracture risk with breast cancer drug


New evidence about the breast cancer drug anastrozole (Arimidex) shows that the incidence of a major side-effect – bone fractures – appears to stabilise after reaching a peak at two years of treatment, easing some of the concerns about the drug.

This finding is the latest to come from evidence provided by the world’s largest international study of breast cancer treatment, the ATAC[1] trial, which compared the aromatase inhibitor anastrozole with breast cancer’s current gold standard hormone treatment tamoxifen, and with both treatments combined.

The trial, involving more than 9,000 post menopausal women in 21 countries, last year revealed that over a median follow-up of patients of 33 months, anastrozole enhanced disease-free survival by 19% and cut the incidence of new tumours in the opposite breast by 58% compared to tamoxifen. This represented an absolute difference of 1.8% in favour of anastrozole. An update at 47 months median follow up showed that the gap had widened to an absolute difference of 2.6% in favour of the newer drug. Overall survival comparisons from the trial should be available next year.

Professor Anthony Howell, chairman of the ATAC steering committee, told a news briefing at ECCO 12 – the European Cancer Conference, that while it was clear that further results were adding to the evidence that anastrozole may in the future supplant tamoxifen doctors needed to be cautious. "We should still wait for that overall survival data next year," he said.

A concern about anastrozole has been the risk of bone fractures. Depriving the body of oestrogen reduces the risk of breast cancer recurring because many breast cancers ’feed’ off this hormone. But, one consequence of oestrogen deprivation is that bones become vulnerable. Aromatase inhibitors such as anastrozole produce profound oestrogen deprivation so it would not be unexpected that women on anastrozole might be more at risk of fractures than those on tamoxifen, a drug that is known to have a mildly positive effect on bone density. Therefore, bone fracture was a pre-defined adverse event in ATAC’s main protocol and one of the important questions posed in the trial was – if anastrozole turned out to be better than tamoxifen at preventing recurrence of breast cancer or of primary tumours in the other breast, would this benefit outweigh the downside of any added incidence of fractures?

Patients’ fracture rates were assessed every six months as a proportion of patients with a first fracture, and these analyses were repeated for fractures of the hip, spine and wrist.

Prof. Howell, a medical oncologist at the Christie Hospital, Manchester, UK said: "We found that at the first analysis, after 31 months median duration of treatment, the incidence of fractures was 5.9% in anastrozole patients compared with 3.7% in tamoxifen patients – nearly 60% greater. But, when the data was updated at 37 months the incidence was 7.1% versus 4.4%, so still around a 60% difference. The risk had not worsened. In fact, the six monthly fracture rates for anastrozole reached a plateau after 24 months with the maximum difference between the two treatments being seen at 18 and 24 months. By the last follow up at 48 months the increase in risk was down to about a third higher for anastrozole. There were similar patterns for fractures of the hip, spine and wrist."

Prof. Howell said: "Anastrozole does lead to an increased bone fracture incidence compared to tamoxifen. But, the positive news is that the fracture rate does appear to peak and then stabilise. So, the overall benefit for patients with early breast cancer remains with anastrozole. We have no idea why the fracture rate stabilises but clearly this is important for patients. It is possible that it will climb again but since the curves have been parallel for some time this seems unlikely.

"It is now important to see what happens when patients stop their treatment after five years and we plan to do bone density measurements at the end of the trial."

The trial shows that the combination of tamoxifen and anastrazole is equivalent to tamoxifen (possibly because anastrozole lowered oestrogen dramatically and there was some evidence that tamoxifen acted as an oestrogen agonist in a low oestrogen environment). It was potentially detrimental, Prof. Howell said, for patients to switch from tamoxifen to anastrozole so the advice was that patients should continue with whichever drug they were on.

He concluded: "It is important that tamoxifen does not suffer from the comparison in this trial because it is still a very good treatment. In developing countries with limited resources to pay for more expensive new drugs it is particularly appropriate to continue to use tamoxifen."

Note: ATAC = Arimidex, Tamoxifen Alone or in Combination. Anastrozole (Arimidex) is an aromatase inhibitor, a class of compounds that inhibit the synthesis of oestrogens from androgens in post-menopausal women.

Further information:
ECCO 12 press office: Sunday 21 September – Thursday 25 September
Tel: 45-3252-4163 or 45-3252-4179
Fax: 45-32524171
Margaret Willson: mobile: 44-797-385-3347 Email:
Mary Rice: mobile: 44-780-304-8897 Email:
Emma Mason: mobile: 44-771-129-6986 Email:

Margaret Willson | EurekAlert!
Further information:

More articles from Health and Medicine:

nachricht Advanced analysis of brain structure shape may track progression to Alzheimer's disease
26.10.2016 | Massachusetts General Hospital

nachricht Indian roadside refuse fires produce toxic rainbow
26.10.2016 | Duke University

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: Etching Microstructures with Lasers

Ultrafast lasers have introduced new possibilities in engraving ultrafine structures, and scientists are now also investigating how to use them to etch microstructures into thin glass. There are possible applications in analytics (lab on a chip) and especially in electronics and the consumer sector, where great interest has been shown.

This new method was born of a surprising phenomenon: irradiating glass in a particular way with an ultrafast laser has the effect of making the glass up to a...

Im Focus: Light-driven atomic rotations excite magnetic waves

Terahertz excitation of selected crystal vibrations leads to an effective magnetic field that drives coherent spin motion

Controlling functional properties by light is one of the grand goals in modern condensed matter physics and materials science. A new study now demonstrates how...

Im Focus: New 3-D wiring technique brings scalable quantum computers closer to reality

Researchers from the Institute for Quantum Computing (IQC) at the University of Waterloo led the development of a new extensible wiring technique capable of controlling superconducting quantum bits, representing a significant step towards to the realization of a scalable quantum computer.

"The quantum socket is a wiring method that uses three-dimensional wires based on spring-loaded pins to address individual qubits," said Jeremy Béjanin, a PhD...

Im Focus: Scientists develop a semiconductor nanocomposite material that moves in response to light

In a paper in Scientific Reports, a research team at Worcester Polytechnic Institute describes a novel light-activated phenomenon that could become the basis for applications as diverse as microscopic robotic grippers and more efficient solar cells.

A research team at Worcester Polytechnic Institute (WPI) has developed a revolutionary, light-activated semiconductor nanocomposite material that can be used...

Im Focus: Diamonds aren't forever: Sandia, Harvard team create first quantum computer bridge

By forcefully embedding two silicon atoms in a diamond matrix, Sandia researchers have demonstrated for the first time on a single chip all the components needed to create a quantum bridge to link quantum computers together.

"People have already built small quantum computers," says Sandia researcher Ryan Camacho. "Maybe the first useful one won't be a single giant quantum computer...

All Focus news of the innovation-report >>>



Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

Agricultural Trade Developments and Potentials in Central Asia and the South Caucasus

14.10.2016 | Event News

World Health Summit – Day Three: A Call to Action

12.10.2016 | Event News

Latest News

How nanoscience will improve our health and lives in the coming years

27.10.2016 | Materials Sciences

OU-led team discovers rare, newborn tri-star system using ALMA

27.10.2016 | Physics and Astronomy

'Neighbor maps' reveal the genome's 3-D shape

27.10.2016 | Life Sciences

More VideoLinks >>>