Estrogen and Progesterone Receptor Testing in Breast Cancer
Key Points
Key Points
A well-performed ER/PgR assay identifies which patients could benefit from to endocrine therapy as treatment after a diagnosis of breast cancer. Additionally, hormone receptor status can be valuable more broadly for tumor classification and other factors that inform treatment.
Globally, more than 1 million women are being diagnosed annually with breast cancer and receptor testing conducted on these biopsies typically discern that approximately 8 in 10 of these women have ER positive breast cancer.
The new guidance reaffirms many of the 2010 recommendations, including that patients with breast cancers having 1–100% ER expression be considered ER positive for the purpose of endocrine therapy decisions. However, new reporting recommendations are made for cases with 1–10% ER expression to acknowledge the more limited data on endocrine responsiveness in this group and overlapping features with ER negative cancers.
The update also has a new recommendation for labs to establish a specific standard operating procedure to ensure the validity of low positive (1–10%) or negative (0 or <1%) interpretations and results. Correlation of ER staining with the histologic features (as well as attention to other standard quality control measures) is also recommended and unusual/discordant results worked up.
The utility of PgR-positive population, but testing using similar principles to ER testing is still recommended for invasive cancers.
Additionally, the updated draft now recommends ER testing for patients diagnosed with ductal carcinoma in situ, but PgR testing is optional.
Diagnosis
...Diagnosis...
...algorithm for ER/PgR testingSamples with 1...
...testing conditions (no change)Large, (prefe...
...issue handling requirements (no chang...
...ernal validation procedures (change a...
...internal QA proceduresOngoing quality con...
...al proficiency assessmentThe laboratory performi...
...aboratory accreditationOn-site inspection...
...ies should include ongoing quality control...
...f any ER result should include evalua...
...oratories should establish and fol...
...tatus of internal controls should be reporte...
...C is the recommended standard test for p...
...in cases of newly diagnosed DCIS (withou...
...ve Breast Cancer Histopathologic Concor...
...ional Recommended Reporting Comments for Sp...
.... Recommendations for Scoring (Readout) and Interp...
Figure 2. Case examples to illustrate stain int...
...legend: Examples of invasive cancers with various...
...gure 3. Internal Controls Figure le...
...al Controls Figure legend: Optimal external (i...