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New Breast Cancer Drug Plan for Older Women?

Switching to Arimidex After 2 Years of Tamoxifen May Provide Benefits for Some Patients

Researchers' Verdict

The researchers call for more studies. But they write that their studies "lend support" to switching from tamoxifen to Arimidex in postmenopausal women with early breast cancer after two years of taking tamoxifen.

They don't recommend Arimidex instead of tamoxifen in newly diagnosed patients. The studies only included women who had already taken tamoxifen for two years.

Second Opinion

The result is "important," writes Anthony Howell, BSc, MBBS, MSc, FRCP, in The Lancet. Howell didn't work on the study, but he wrote an editorial about it. Howell works at the Cancer Research U.K. Department of Medical Oncology at Christie Hospital NHS Trust in Manchester, England.

"The aromatase inhibitors improve substantially on tamoxifen, which is, in turn, substantially superior to placebo," writes Howell. He notes controversy about whether aromatase inhibitors should totally replace tamoxifen.

Howell writes that aromatase inhibitors are regarded as having a better side-effect profile than tamoxifen because of significantly reduced rates of uterine cancers, clotting problems, and hot flashes. This must be set against the increased rates of fractures and joint aches, and vaginal dryness and painful sex, which can be troublesome in a smaller number of patients, he writes.

Howell notes that aromatase inhibitors seem to have broadly similar side effects, apart from apparent small increases in heart toxicity with Femara and Aromasin, an effect not apparent with Arimidex. "These apparent increases might be the play of chance but clearly need to be monitored carefully," writes Howell.

"Until we have answers to all our questions, we should base the decision of when to use an aromatase inhibitor, and which to use, on the availability and maturity of data in the appropriate clinical setting," he writes.

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