Taking adjuvant endocrine therapy for 7 to 8 years is likely sufficient for maximal disease-free survival (DFS) benefits among most postmenopausal women with hormone receptor (HR)-positive breast cancer, according to researchers.

In a meta-analysis, researchers found that 10 years of adjuvant endocrine therapy did not provide additional benefits for most patients, but patients with node-positive disease had improved DFS with 10 years of treatment.

The meta-analysis, published in the European Journal of Cancer, included 12 studies of postmenopausal patients who underwent surgery for HR-positive, HER2-negative early breast cancer. The patients had received at least 5 years of adjuvant therapy with any approved endocrine agent, such as tamoxifen followed by an aromatase inhibitor or an aromatase inhibitor alone.

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The DFS was significantly longer when endocrine therapy was extended by 2 to 3 years beyond the initial 5 years of treatment (hazard ratio [HR], 0.77; 95% CI, 0.69-0.87).

Overall, an additional 5 years of endocrine therapy beyond the initial 5 years did not significantly improve DFS, compared with an additional 2 to 3 years (HR, 0.97; 95% CI, 0.88-1.08) or 3 to 4 years (HR, 0.87; 95% CI, 0.72-1.06).

For patients with node-positive disease, however, an additional 5 years of endocrine therapy significantly prolonged DFS compared with an extension of 2 to 3 years (HR, 0.86; 95% CI, 0.75-0.99) or no extension of endocrine therapy (HR, 0.75; 95% CI, 0.67-0.84).

An additional 5 years of endocrine therapy was also associated with longer DFS among patients treated with tamoxifen during their initial 5 years of adjuvant therapy. A formal analysis was not conducted, but the researchers said a longer duration of tamoxifen treatment was associated with a greater benefit of additional years of treatment with aromatase inhibitors.

Extended treatment with endocrine therapy did not affect overall survival (OS). OS was comparable with an additional 2-3 years of therapy or an additional 5 years of therapy (HR, 0.92; 95% CI, 0.8-1.6).

Based on these results, the researchers concluded that an extended duration of endocrine therapy — 7 to 8 years in total — could be considered an appropriate treatment regimen for the DFS benefit. However, 10 years of treatment should be considered a potential standard of care for patients with positive lymph nodes.


Petrelli F, Cavallone M, Dottorini L. 10 years or less of extended adjuvant endocrine therapy for postmenopausal breast cancer patients: A systematic review and network meta-analysis. Eur J Cancer. Published online September 6, 2023. doi:10.1016/j.ejca.2023.113322