There is good news for patients suffering from a type of early stage breast cancer called estrogen receptor (ER)-positive and HER2-negative breast cancer. Many of these patients are overtreated and do not require chemotherapy.
A 2018 US study found that endocrine therapy alone is adequate for treating women with ER-positive and HER2-negative early stage breast cancer.
Gene expression profiling of the tumour determines objectively if patients will benefit from endocrine therapy alone. There are several of these tests such as Oncotype DX, EndoPredict and Mammaprint to guide decisions for treatment.
Oncotype DX is a test that has been validated to predict the risk of relapse with endocrine therapy alone as well as the additional benefit from chemotherapy by assessing 21 genes in the tumour. A recurrence score of less than 25 indicates that there is no proven benefit of adding chemotherapy to endocrine treatment in women with limited or no lymph node involvement.
With this insight, many early stage breast cancer patients in Singapore need not suffer the side effects of chemotherapy when undergoing treatment for breast cancer.
To learn more about breast cancer biomarker assays (such as Oncotype DX, EndoPredict and Mammaprint) or seek treatment advice for breast cancer, consult oncologist Dr Lynette Ngo.