In a French study reported in the Journal of Clinical Oncology, Dumas et al found that improved endocrine therapy (ET) persistence among young patients with hormone receptor (HR)-positive early breast cancer would likely lead to improved disease-free survival.
Study Details
The study used data from the French National Health Data System. Three ET persistence patterns were assessed, consisting of allowing treatment gaps of no more than 30, 90, or 180 continuous days; 5-year disease-free survival benefits of sustained ET persistence vs observed persistence were estimated.
Key Findings
A total of 121,601 patients with HR-positive early breast cancer were included in the analyses, with 29.8% younger than age 50 years at diagnosis.
Younger patients had lower 5-year disease-free survival and were more likely to discontinue ET vs older patients. Among patients aged ≤ 34 years, strict ET persistence (≤ 30-day gaps) improved 5-year disease-free survival from 74.5% to 78.8% (absolute difference = 4.3%, 95% confidence interval [CI] = 2.6%–7.2%) vs observed persistence. The 5-year disease-free survival benefit in patients aged ≤ 34 years was reduced among patients with ≤ 90-day gaps (absolute difference = 1.3%, 95% CI = 0.2%–3.7%) and ≤ 180-day gaps (absolute difference = 1.0%, 95% CI = –0.2% to 3.4%).
The disease-free survival benefits of improved ET persistence in patients aged > 50 years did not exceed an absolute 1.9 percentage points vs observed persistence, irrespective of persistence definition examined.
The investigators concluded: “The survival benefit that could be achieved with strict ET persistence in women 34 years and younger with HR-positive [early breast cancer] highlights the need for tailored strategies to improve ET persistence in this population.”
Elise Dumas, PhD, of Université Paris Cité, is the corresponding author for the Journal of Clinical Oncology article.
Disclosures: The study was supported by Monoprix and the Swiss National Science Foundation. For full disclosures of the study authors, visit ascopubs.org.
