These data are more robust than the efficacy signals from previous studies, meaning healthcare providers should not recommend aspirin as adjuvant therapy for breast cancer, reported lead author Wendy Y. Chen, MD, of Dana Farber Cancer Institute, Boston, and colleagues.
What Data Support Aspirin for Treating Breast Cancer?
“Multiple observational studies have reported a decreased risk of death among survivors of breast cancer who were regular aspirin users,” the investigators wrote in JAMA. “Even more compelling were data from randomized trials of aspirin for cardiovascular disease.”
This possible benefit was reported with mechanistic support, as aspirin’s anti-inflammatory and anti-platelet properties could theoretically control tumor growth, they added. Furthermore, aspirin impacts several cancer pathways currently targeted by agents approved by the US Food and Drug Administration (FDA).
Brigham & Women's Hospital
Dr. Wendy Y. Chen
“Collectively, evidence from laboratory and epidemiologic studies and randomized trials strongly suggested a role for aspirin to improve breast cancer outcomes, leading to [this new study, Alliance for Clinical Trials in Oncology (Alliance) A011502,] which, to our knowledge, is the first randomized, placebo-controlled trial of aspirin to report results among survivors of breast cancer,” Dr. Chen and colleagues wrote.
What Were The Key Findings From The A011502 Trial?
The A011502 trial enrolled 3,020 patients aged 18-70 years with ERBB2-negative breast cancer who had received standard therapy via routine clinical care. Eligibility required that chemotherapy and local therapy were complete, but ongoing endocrine therapy was allowed.
Participants were randomized in a 1:1 ratio to receive aspirin 300 mg per day or matching placebo for 5 years. The primary outcome was invasive disease-free survival, and the key secondary outcome was overall survival.
After a median follow-up of almost 3 years, at the first interim analysis, the study was suspended early due to statistical futility. By that timepoint, 253 invasive disease-free survival events occurred, of which 141 occurred in the aspirin group, compared with 112 in the placebo group, providing a hazard ratio of 1.27 (95% CI, 0.99-1.63) that was not statistically significant (P = .06). No statistically significant difference in overall survival was observed (hazard ratio, 1.19; 95% CI, 0.82-1.72). Safety profiles were similar across groups.
How Will This Study Change Practice?
In an accompanying editorial, Jeanne S. Mandelblatt, MD, of Georgetown Lombardi Institute for Cancer and Aging Research, Washington, and colleagues, praised the trial for its comprehensive approach, but they predicted that the negative result could spell friction for health care providers.
“[C]linicians may find it challenging to communicate with their patients about the negative result in the Alliance trial, because prior lay press articles, observational studies, and meta-analyses of cardiovascular trials suggested that aspirin may decrease breast cancer recurrence,” they wrote.
Georgetown University
Dr. Jeanne S. Mandelblatt
Dr. Mandelblatt and colleagues went on to explore broader implications beyond breast cancer, including considerations for communication of negative results in other medical specialties, discussions between clinicians and patients regarding aspirin use for non–breast cancer purposes, and questions about the timing of aspirin use and the role of age and biological aging.