The following article features coverage from the San Antonio Breast Cancer Symposium (SABCS) 2017 meeting. Click here to read more of Cancer Therapy Advisor‘s conference coverage.

Extending adjuvant bisphosphonate therapy does not improve disease-free survival (DFS) or overall survival (OS) among women with high-risk breast cancer, according to phase 3 study results presented at the 2017 San Antonio Breast Cancer Symposium.1

“At this early time point, our study showed no difference in DFS or OS between 5 years and 2 years of adjuvant zoledronate treatment following adjuvant chemotherapy in high-risk early breast cancer patients, regardless of menopausal status,” reported lead study author Wolfgang Janni, MD, PhD, of the University Hospital Ulm in Germany.

Extended 5-year zoledronate treatment was, however, associated with an increased frequency of adverse events (AEs; all grades: 46.2% vs 27.2%; P < .001; grade 3 to 4 AEs: 7.6% vs 5.1%; P = .006).

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Patients were randomly assigned to undergo adjuvant chemotherapy with 3 cycles of fluorouracil, epirubicin, and cyclophosphamide (FEC) followed by either 3 cycles of docetaxel or 3 cycles of gemcitabine-docetaxel. Upon completion of chemotherapy, patients were again randomly assigned to receive 5 years or 2 years of zoledronate therapy. The median follow-up was 3 years.

Nearly 3000 patients were available for analysis (1540 in the 5-year zoledronate group and 1447 patients in the 2-year group). Neither adapted DFS nor OS differed between the groups in multivariate analyses adjusted for patient and tumor variables and chemotherapy (hazard ratio [HR] for DFS, 0.97; 95% CI: 0.75-1.25; P = .8; HR for OS, 0.98; 95% CI: 0.67-1.42; P = .9).

Menopausal status was not associated with DFS or OS differences between the treatment groups, though the subanalysis was based on small number of events.

“In the absence of decreased bone density, 5 years of adjuvant zoledronate treatment should not be considered in these patients.” Dr Janni added.

Read more of Cancer Therapy Advisor‘s coverage of the San Antonio Breast Cancer Symposium (SABCS) 2017 meeting by visiting the conference page.

Reference

  1. Janni, W, Friedl TW, Fehm T, et al. Extended adjuvant bisphosphonate treatment over five years in early breast cancer does not improve disease-free and overall survival compared to two years of treatment: phase III data from the SUCCESS A study. Oral Presentation at: 2017 San Antonio Breast Cancer Symposium; December 5-9, 2017; San Antonio, TX.