SAN ANTONIO — Results from a German study demonstrated no improvement in disease-free survival among patients with breast cancer who were treated with dose-dense chemotherapy and the bisphosphonate ibandronate.
Volker Möbus, Ph.D., head of the department of obstetrics and gynecology at Klinikum Frankfurt Höchst GmbH in Frankfurt, presented the results from the German Adjuvant Intergroup Node Positive (GAIN) Study, at the 2011 CTRC-AACR San Antonio Breast Cancer Symposium, held Dec. 6-10, 2011.
Möbus and his colleagues randomly assigned 3,023 patients with breast cancer to two different chemotherapy regimens and then further assigned them to 50 milligrams of oral ibandronate or observation. After a median follow-up of 38.7 months, “we found no significant difference between groups in the primary endpoint” of disease-free survival, Möbus said.
He described these results as “disappointing” compared with other studies. In the Adjuvant Treatment with Zoledronic Acid in Stage II/III Breast Cancer (AZURE) trial, for example, Möbus said that the subgroup of postmenopausal patients showed an improvement in recurrence-free and overall survival.
“So far, clinical trials of adjuvant bisphosphonates in early breast cancer have shown variable results, independent from their application (oral compared with intravenous),” Möbus said.
More recently, two trials — the Austrian Breast & Colorectal Study Group (ABCSG-12) and the Zometa-Femara Adjuvant Synergy Trial (ZO-FAST) — have shown significant benefit in patients with hormone receptor-positive breast cancer who were postmenopausal and received an endocrine treatment only.
Möbus said that in the AZURE trial, 95 percent of patients received chemotherapy and only postmenopausal patients showed an improvement in the zoledronic acid group. “In our [GAIN] trial, all patients received dose-dense chemotherapy, and unfortunately, we could not show a benefit in any subgroup,” he said. “We speculate that the high efficacy of dose-dense chemotherapy erases the potential effect of bisphosphonates, which is shown in patients with endocrine treatment only.”
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The mission of the CTRC-AACR San Antonio Breast Cancer Symposium is to produce a unique and comprehensive scientific meeting that encompasses the full spectrum of breast cancer research, facilitating the rapid translation of new knowledge into better care for patients with breast cancer. The Cancer Therapy & Research Center (CTRC) at The University of Texas Health Science Center at San Antonio, the American Association for Cancer Research (AACR) and Baylor College of Medicine are joint sponsors of the San Antonio Breast Cancer Symposium. This collaboration utilizes the clinical strengths of the CTRC and Baylor and the AACR’s scientific prestige in basic, translational and clinical cancer research to expedite the delivery of the latest scientific advances to the clinic. The 34th annual symposium is expected to draw nearly 8,000 participants from more than 90 countries.