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De‐escalation of five‐year adjuvant endocrine therapy in patients with estrogen receptor‐low positive (immunohistochemistry staining 1%‐10%) breast cancer: Propensity‐matched analysis from a prospectively maintained cohort
Author(s) -
Cai YuWen,
Shao ZhiMing,
Yu KeDa
Publication year - 2022
Publication title -
cancer
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.052
H-Index - 304
eISSN - 1097-0142
pISSN - 0008-543X
DOI - 10.1002/cncr.34155
Subject(s) - medicine , breast cancer , hazard ratio , propensity score matching , oncology , proportional hazards model , adjuvant therapy , cancer , prospective cohort study , estrogen receptor , cohort , confidence interval , gynecology
Background The standard 5 years of endocrine therapy has demonstrated additional benefits compared with short‐term (2‐3 years) treatment in patients with estrogen receptor (ER)‐positive breast cancer; however, data specific to ER‐low positive breast cancer (1%‐10% by immunohistochemistry) are limited, and it is unclear whether long‐term treatment is still necessary for this subgroup. Methods The authors used the prospectively maintained Breast Surgery Database of Fudan University Shanghai Cancer Center for this propensity‐matched analysis. The primary end point was disease‐free survival. Multivariate Cox regression analysis and propensity score‐matching methods were used to minimize bias. Hazard ratios (HRs) with 95% confidence intervals (CIs) were calculated. All statistics were 2‐sided. Results From 2012 to 2017, 22,768 consecutive women had pathologically confirmed, early stage breast cancer, and 1013 (4.45%) were identified with ER‐low positive disease. Among these, 634 patients met the inclusion criteria and were divided into 3 groups: those who received no endocrine therapy (n = 89), those who received 2 to 3 years of endocrine therapy (n = 185), and those who received approximately 5 years of endocrine therapy (n = 360). At a median follow‐up of 65 months, there was no significant difference in disease‐free survival between patients who received 2 to 3 years and 5 years of endocrine therapy (HR, 0.82; 95% CI, 0.51‐1.33; P = .43). The findings were consistent after multivariate Cox analysis of the propensity score‐matched samples (5 vs 2‐3 years of treatment: HR, 0.74; 95% CI, 0.41‐1.31; P = .30). Conclusions Short‐term endocrine therapy for 2 to 3 years might be an alternative for patients who have ER‐low positive breast cancer instead of the standard 5 years of treatment.