New Drug Beats Tamoxifen at Keeping Women Cancer Free

The aromatase inhibitor drug anastrozole (Arimidex) continues to outpace the old standard tamoxifen (Nolvadex) when it comes to preventing recurrences of hormonereceptor-positive breast cancers in postmenopausal women.

Even three years after treatment was stopped, women taking Arimidex still saw a benefit, researchers said.

"It has been very good news," said Aman Buzdar, MD, US principal investigator of the ATAC (Arimidex or Tamoxifen Alone or in combination) trial. "A lot more women receiving Arimidex are free of cancer compared to tamoxifen, and the 100-month data show that these differences, if anything, with time actually continued to increase-meaning there were fewer and fewer recurrences on Arimidex compared with tamoxifen," Dr. Buzdar said.

"Arimidex is the standard of care for postmenopausal women with receptor-positive breast cancer," confirmed Jay Brooks, MD, chairman of hematology/oncology at Ochsner Health System in Baton Rouge, Louisiana. "One hundred months (over eight years) of follow-up is very profound."

Background

Hormone-receptor-positive cancers respond to circulating hormones estrogen or progesterone. Experts estimate that from 50% to 70% of breast cancers are hormone receptor positive.

Arimidex is an aromatase inhibitor, a relatively new class of compounds that blocks estrogen production in the body. According to Dr. Buzdar, who is professor of medicine and deputy chair of the department of breast medical oncology at the University of Texas M.D. Anderson Cancer Center, Arimidex is now indicated for postmenopausal women who have a hormonedependent cancer.

Tamoxifen, which has been the gold standard of care in breast cancer treatment for more than 20 years, hinders the tumor's ability to use estrogen. Because Arimidex does not interfere with ovarian function, premenopausal women with active ovaries should still use tamoxifen, Dr. Buzdar said.

The first major results from ATAC, reported in 2001, found that Arimidex was more effective than tamoxifen in preventing breast cancer recurrence and was better tolerated.

New Study

The current data represent five years of active treatment plus three additional years of followup. In all, more than 9,000 women in 21 countries were involved in the study.

All the women had early-stage disease and had undergone surgery with or without chemotherapy and/or radiation. The mean age of participants was 72 years and 84% had hormone-receptor-positive tumors.

The women were randomized to receive Arimidex alone or tamoxifen alone.

New Findings

Arimidex improved disease-free survival by 15% compared with tamoxifen in women with hormone-receptor-positive breast cancer. The drug reduced the risk of all recurrences by 24%.

The improvement persisted even after treatment was stopped.

"The other question which was in all of our minus was what happens after you stop the pill," Dr. Buzdar said. "But the pill was stopped three years ago, and we're still seeing the effects. Even after stopping therapy, there are fewer recurrences in people who took Arimidex in the past."

The most common side effects were joint pain and estrogen deprivation leading to osteoporosis. Once the pill was stopped, however, a woman's risk of developing osteoporosis returned to normal. No additional side effects were observed.

"Not only are you keeping more patients alive free of disease, but the safety profile is much more predictable and much more favorable than tamoxifen," Dr. Buzdar said.

Breast Cancer Treatment Increases Survival Rate

Women with early-stage breast cancer who took tamoxifen for two to three years, then an aromatase inhibitor (AI), such as anastrazole (Arimidex) or letrozole (Femara), were less likely to have a recurrence than women who kept taking tamoxifen.

Caution: Women taking Als should be monitored for high cholesterol, musculoskeletal disorders and heart disease.

Fight Forgetfulness Caused by Chemo

Forgetfulness may result from breast cancer treatment. Patients who had chemotherapy for breast cancer reported having reduced memory even 10 years after treatment. The condition, called "chemobrain," was previously thought to be short-term.

To keep memory sharp: Do crossword puzzles... exercise, eat well and be sure to get enough sleep.

If symptoms persist a year after treatment: Consult a neuropsychologist.

Higher-Dose Chemo Lowers Cancer Recurrence by 22%

Older breast cancer patients benefit from higher-dose chemotherapy as much as younger patients do. Otherwise healthy patients age 65 and older have about the same lowered recurrence rate—approximately 22%—as younger patients.

Doctors tend to underuse chemotherapy in older patients because of its side effects, such as weakness and nausea.