Hormonal Therapy Confers Clinically Relevant Benefit in Breast Cancers with Low Estrogen Receptor Expression

Suaad A Alaghbari, Serene EL Tang, Bernard CS Ho, Pei Yi Sin, Sherwin Kuah, Juliana JC Chen, Sarah QH Lu, Mui Heng Goh, Patrick MY Chan and Ern Yu Tan

Department of General Surgery, Tan Tock Seng Hospital, Singapore
Department of Pathology, Tan Tock Seng Hospital, Singapore

^*Correspondance to: Ern Yu Tan 

 PDF  Full Text DOI: 10.25107/2474-1647.2484

Abstract

Background: Breast tumors with low Estrogen Receptor (ER) expression cluster more closely with ER-negative tumors on a molecular level and may not derive the same benefit from hormonal therapy as ER-positive tumors. In this study, we examined the effect of hormonal therapy on survival outcomes in low ER-positive tumors. Methods: Retrospective review was done of 2872 women diagnosed with breast cancer at Tan Tock Seng Hospital from 2001 to 2012. Low ER-positive tumors were defined as tumors where 1% to 9% of cells stained positive for ER. Results: Low ER-positive tumors were found in 171 women, 70% of whom received hormonal therapy. Compared to tumors demonstrating at least 10% ER expression, low ER-positive tumors were more common in younger (P<0.001), non-Chinese (P=0.018) women and were more likely to be high grade (P=0.003 and P<0.001 for DCIS and invasive cancers respectively), Progesterone Receptor (PR)-negative (P<0.001) and human epidermal growth factor receptor (HER)-2 overexpressing (P<0.001). Distant disease-free survival among low ER-positive tumors was significantly worse compared to tumors expressing at least 10% ER (P=0.005), but closely overlapped that of ER-negative tumors (P=0.574). Nevertheless, hormonal therapy was still found to reduce disease recurrence, both locoregional and distant, in women with low ER-positive tumors (P=0.042 and P<0.001 respectively) and improved 10-year distant disease-free and overall survival outcomes (P<0.001 and P=0.004 respectively). An advanced stage at presentation (P=0.002,), PR-negativity (P=0.042) and the omission of hormonal therapy (P<0.001) increased the risk of distant recurrence in women with low ER-positive tumors. Conclusion: Hormonal therapy conferred clinical benefit in low ER-positive tumors and should be considered especially in those with advanced or PR-negative tumors who are at high risk of distant recurrence.

Keywords

Low ER expression; Hormonal therapy; Survival

Cite the article

Alaghbari SA, Tang SEL, Ho BCS, Sin PY, Kuah S, Chen JJC, et al. Hormonal Therapy Confers Clinically Relevant Benefit in Breast Cancers with Low Estrogen Receptor Expression. Clin Surg. 2019; 4: 2484.