Optimal duration of adjuvant endocrine therapy for ER-low positive breast cancer

The standard 5 years of endocrine therapy has demonstrated additional benefits compared with short-term (2-3 years) treatment among patients with estrogen receptor (ER)-positive breast cancer. Data specific to ER-low positive breast cancer (1%-10% by immunohistochemistry) are limited, and it is unclear whether long-term treatment is necessary for this subgroup. Propensity-matched analysis of the prospectively maintained Breast Surgery Database of Fudan University Shanghai Cancer Center found that among patients with ER-low positive breast cancer with a median follow-up of 65 months, there was no significant difference in disease-free survival between patients who received 2 to 3 years versus 5 years of endocrine therapy. The authors conclude that endocrine therapy for 2 to 3 years might be an alternative for this patient group.