ATLANTA — Postmenopausal women with breast cancer who undergo adjuvant chemotherapy with anthracycline have a significantly increased long-term risk of developing heart failure, researchers reported at the annual meeting of the American Society of Clinical Oncology.
Women aged 66–70 who received anthracycline-based chemotherapy had a 38% higher risk of developing heart failure, compared with women of similar age treated with nonanthracycline chemotherapy regimens, said Dr. Sharon H. Giordano, professor of medicine at the University of Texas M.D. Anderson Cancer Center, Houston.
Data are scant on the long-term cardiac safety of anthracycline chemotherapy in women over age 65, Dr. Giordano said in an interview.
Long-term rates and predictors of heart failure were evaluated in a population-based cohort of older women in Medicare's Surveillance, Epidemiology and End Results (SEER) registry, which collects data on U.S. incident cancer rates. Women aged 66–90 years old with invasive breast cancer diagnosed in 1992–1999 were included.
The 31,326 women were placed in one of three groups: 27,324 received no adjuvant chemotherapy, 1,682 received adjuvant anthracyclines, and 2,320 were treated with adjuvant nonanthracycline chemotherapy. A total of 7,414 patients had subsequent claims for heart failure.
Patient characteristics differed in each group. Those “who did not receive chemotherapy were older and had higher comorbidities than did the patients in the other two groups. The anthracycline-treated group was slightly younger and healthier than the nonanthracycline chemotherapy group,” Dr. Giordano said.
Despite being younger and healthier at baseline, a substantially higher proportion of the anthracycline-treated patients had developed heart failure after 10 years.
“At 5 years of follow-up, 85% of anthracycline-treated patients remained free of heart failure, as compared to 88% of other patients,” Dr. Giordano said. At 10 years, the differences were more pronounced, with 61% of anthracycline-treated patients being free of heart failure, compared with 74% of those treated with nonanthracycline regimens and 73% of women who received no chemotherapy.
But in women aged at least 71 years, there were no differences among the three groups. This might be the result of older women being given lower doses of adjuvant therapy or to selection bias in which only the healthiest patients would be eligible for anthracycline, she said.
Despite being healthier at baseline, more anthracycline-treated patients developed heart failure. DR. GIORDANO