Find Information About:

Drugs & Supplements

Get information and reviews on prescription drugs, over-the-counter medications, vitamins, and supplements. Search by name or medical condition.

Pill Identifier

Pill Identifier

Having trouble identifying your pills?

Enter the shape, color, or imprint of your prescription or OTC drug. Our pill identification tool will display pictures that you can compare to your pill.

Get Started
My Medicine

My Medicine

Save your medicine, check interactions, sign up for FDA alerts, create family profiles and more.

Get Started

WebMD Health Experts and Community

Talk to health experts and other people like you in WebMD's Communities. It's a safe forum where you can create or participate in support groups and discussions about health topics that interest you.

  • Second Opinion

    Second Opinion

    Read expert perspectives on popular health topics.

  • Community


    Connect with people like you, and get expert guidance on living a healthy life.

Got a health question? Get answers provided by leading organizations, doctors, and experts.

Get Answers

Sign up to receive WebMD's award-winning content delivered to your inbox.

Sign Up

Breast Cancer Health Center

Font Size

Drug Switch Ups Breast Cancer Survival

After 2-3 Years of Tamoxifen, Switch to Arimidex May Lower Death Risk
WebMD Health News
Reviewed by Louise Chang, MD

Nov. 17, 2006 -- Postmenopausal breast cancer survivors do best if they switch to Arimidex after two to three years of tamoxifen therapy.

The finding comes from an analysis of clinical trial data funded by AstraZeneca, the company that makes Arimidex. AstraZeneca is a WebMD sponsor.

The study itself was performed by Walter Jonat, MD, of the University of Kiel, Germany; Michael Gnant, MD, of the University of Vienna, Austria; and colleagues.

Jonat's team combined data from three studies of postmenopausal women who, after breastcancer surgery, took tamoxifen (brand name, Nolvadex) to prevent their cancers from coming back. After two or three years of tamoxifen therapy, some of these women switched to Arimidex.

In the combined analysis, there were about 2,000 women in each group. Those who switched to Arimidex did better than those who stayed on tamoxifen:

  • The Arimidex group had a 29% lower risk of death.
  • The Arimidex group had a 41% higher chance of disease-free survival.
  • The Arimidex group had a 45% lower chance of cancer relapse in any part of the body.

Arimidex is in a class of drugs known as nonsteroidal aromatase inhibitors. Another drug in this class, Femara, is made by Novartis. Aromasin, made by Pfizer, is a steroidal aromatase inhibitor. Novartis and Pfizer are WebMD sponsors.

These drugs block an enzyme the body uses to make estrogen, thereby suppressing estrogen levels throughout the body. After surgery, they help prevent cancer recurrence in women who have had estrogen-sensitive breast cancer.

Some women and their doctors choose to start treatment with aromatase inhibitors. Many doctors, however, start with tamoxifen and switch to aromatase inhibitors after five years.

"A lot of people have been waiting to see whether aromatase inhibitors will show a survival advantage, and I think this data will assure them that five years of tamoxifen is no longer the standard of care," Jonat said in a news release. "The best treatment for women with hormone-sensitive early-stage breast cancer should include an aromatase inhibitor."

Jonat and colleagues note that their analysis is not proof that women should switch to aromatase inhibitors after two or three years of tamoxifen. Such proof can come only from clinical trials. Such trials currently are underway.

Jonat and colleagues report their findings in the Nov. 17 online edition of The Lancet Oncology.

Today on WebMD

Breast Cancer Overview
From self-exams and biopsies to reconstruction, we’ve got you covered.
Dealing with breast cancer
Get answers to your questions.
woman having mammogram
Experts don’t agree on all fronts, but you can be your own advocate.
woman undergoing breast cancer test
Many women worry. But the truth? Most abnormalities aren’t breast cancer.
Breast Cancer Treatments Improving
Resolved To Quit Smoking
Woman getting mammogram
Screening Tests for Women
ovarian cancer overview slideshow
serious woman
what is your cancer risk
10 Ways to Revitalize Slideshow