Katherine E. Reeder-Hayes, MD, MBA
A comparative analysis of outcomes with two different trastuzumab (Herceptin)-based adjuvant regimens in older women with early HER2-positive breast cancer found little difference in safety and efficacy between treatments. The study was reported by Katherine E. Reeder-Hayes, MD, MBA, of the University of North Carolina at Chapel Hill, and colleagues in the Journal of Clinical Oncology.
The study involved analysis of linked Surveillance, Epidemiology, and End Results (SEER)-Medicare data for 2005 to 2013 for outcomes with doxorubicin, cyclophosphamide, paclitaxel, and trastuzumab (ACTH) vs docetaxel, carboplatin, and trastuzumab (TCH) in women aged > 65 years with HER2-positive breast cancer. These regimens have not been directly compared in a clinical trial, and available data provide little guidance on their use in older patients. Propensity score matching was used to balance patient characteristics between treatment groups.
The population included 1,077 patients, of whom 365 received ACTH and 712 received TCH. The propensity score–matched subgroup included 208 women in each group. Use of TCH increased over time, with the proportion receiving ACTH decreasing from 88% in 2005 to 15% in 2011.
Safety and Efficacy
Hospital stays due to adverse events within 6 months of beginning therapy occurred in 21% of the ACTH group vs 24% of the TCH group in the overall cohort (P = .26); for total emergency and observation visits, hospital services were used by 34% vs 36.5% (P = .46). In the propensity score–matched groups, no significant differences were observed in the frequency of chemotherapy-related adverse events.
Patients receiving TCH were significantly more likely to complete trastuzumab treatment (89% vs 77%, P = .001). No significant differences were observed between the ACTH and TCH groups with regard to 5-year breast cancer–specific survival (92% vs 96%, hazard ratio [HR] = 2.08, 95% confidence interval [CI] = 0.90–4.82) or 5-year overall survival (90% vs 92%, HR = 1.22, 95% CI = 0.63–2.35).
The investigators concluded: “Among a matched sample of older patients, ACTH compared with TCH was not associated with a higher rate of serious adverse events or hospitalizations, but it was associated with less completion of adjuvant trastuzumab. We did not detect a difference in 5-year survival outcomes for ACTH compared with TCH. In the context of limited evidence in older patients, selection between these two regimens on the basis of concerns about differential toxicity or efficacy may not be appropriate.”
Reeder-Hayes KE, et al: J Clin Oncol. July 20, 2017 (early release online).