European guidelines on breast cancer screening and diagnosis

If you have been diagnosed with invasive breast cancer, what threshold of positive hormone receptors should be used to make adjuvant endocrine therapy advisable?

The ECIBC's Guidelines Development Group (GDG) suggests using adjuvant endocrine therapy if 1% or more of the tumour cells show oestrogen or progesterone receptor positivity.

You have been diagnosed with invasive breast cancer.

You may wish to speak with your healthcare professional about how the hormone receptor positivity is tested and about the efficacy of endocrine therapy as treatment for invasive breast cancer. 

You may also wish to speak about the risk of cancer returning after treatment.

Increasing the threshold for breast tumour hormone receptor positivity from 1 to 10% of tumour cells means that women whose cancers fall into this group will not receive endocrine therapy. While this may have little or no effect on the chance of their cancer returning, it may also result in some women who might benefit from endocrine treatment not receiving it.

In breast cancer, hormone receptors are proteins located in and around breast cells that signal cells to grow.

Adjuvant endocrine therapy is a type of treatment given after surgery to women who have a positive hormone receptor test. It lowers or stops oestrogen/progesterone from acting on breast cancer cells and keeps cancer from growing and spreading.

The knowledge of hormone receptor status (oestrogen receptor (ER) and/or progesterone receptor (PR) status) of an invasive breast cancer may facilitate early treatment planning with endocrine therapy. Different hormone receptor thresholds are used to categorise a tumour as hormone receptor positive and to recommend endocrine therapy to those patients.