Aspirin Unlikely to Improve Breast Cancer Survival: Evidence From a Major Clinical Trial

Aspirin in Breast Cancer Treatment: A Misguided Hope?

Despite aspirin's availability and promising observational studies implying a potential for improving breast cancer survival rates, a recent definitive clinical trial suggests otherwise. The study, published in JAMA and conducted by a team led by Wendy Y. Chen, MD, from Dana-Farber Cancer Institute, tested the efficacy of aspirin as an adjuvant therapy in breast cancer patients at a dose of 300 mg/day for 5 years.

Trial Specifics and Outcomes

The phase 3, randomized, double-blind, placebo-controlled trial included 3,020 participants with high-risk nonmetastatic breast cancer, enrolled across the United States and Canada from January 6, 2017, to December 4, 2020, with follow-up until March 4, 2023.

Despite high hopes, the study was halted at the first interim analysis when the data suggested that continuing would be futile. The primary measure, invasive disease-free survival (IDFS), did not show significant improvement in the aspirin cohort (hazard ratio of 1.27, not statistically significant). Additionally, the secondary outcome of overall survival was not markedly different between those taking aspirin and those on placebo.

Adverse Events: A Neutral Stance

The rates of grades 3 and 4 adverse events were similar in the aspirin and placebo groups, indicating no remarkable increase in severe side effects due to aspirin therapy.

Interpreting the Results: Caution Ahead

This study, while demonstrating the safety of aspirin, challenges the notion that it could be a game-changer in breast cancer therapy. Given the hopeful evidence from earlier observational studies and the biological rationale involving aspirin’s anti-inflammatory properties, these findings are certainly a disappointment to many.

The researchers caution against the routine use of aspirin for improving breast cancer outcomes, emphasizing that the decision on whether to initiate or continue aspirin therapy should be individually tailored, considering the potential risks and benefits, rather than based on an expectation of reduced cancer risk.

Current Perspective on Aspirin and Cancer

While aspirin's role in breast cancer now seems unlikely to offer the survival benefits once hoped for, its utility in other cancer types or in prevention should not be dismissed. Current and future investigations may yet identify specific cases where aspirin could be beneficial. However, for breast cancer, the search for effective adjuvant therapies continues.

Acknowledgements and Future Directions

The study was supported by the Department of Defense Breast Cancer Research Program, the National Cancer Institute, Bayer (providing the study drug), and additional groups. Researchers indicate that while aspirin may not be the adjuvant therapy breast cancer patients were hoping for, it remains crucial to seek other avenues that could improve survival rates in this population.

Full Details and Acknowledgements

For an in-depth look into the study, titled "Aspirin vs Placebo as Adjuvant Therapy for Breast Cancer The Alliance A011502 Randomized Trial," see the original publication in JAMA. Acknowledgements are due to all participants, healthcare providers, Linda McCall, MS for statistical analysis, and patient advocates Carol Matyka, BA, and Margaret Carvan, MPA for their contributions.

About the Source

This trial was registered under ClinicalTrials.gov Identifier: NCT02927249 and has been shared in detail by Oregon Health & Science University. Built with the help of Buoy Health.

This summary provides a high-level overview of key findings from a clinical trial examining the impact of aspirin on breast cancer outcomes. It aims to present essential information in a digestible format for readers and is not intended to replace a thorough review of the original research document for those seeking detailed insights.