Estrogen and Progesterone Receptor Testing in Breast Cancer
Key Points
Key Points
- The College of American Pathologists (CAP) and the American Society of Clinical Oncology (ASCO) convened an expert panel to consider new evidence or emerging data that might prompt changes to clinical practices that were established with the 2010 ASCO/CAP Guideline Recommendations for Immunohistochemical (IHC) Testing of Estrogen and Progesterone Receptors (ER/PgR) in Breast Cancer.
- 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
...iagnosi...
...thm for ER/PgR testingSamples with 1-100...
...ing conditions (no change)Large, (prefer...
Optimal tissue handling requirements (n...
...mal internal validation procedures (ch...
...nternal QA proceduresOngoing quality contr...
...ternal proficiency assessmentThe laboratory per...
...tory accreditationOn-site inspection every ot...
...should include ongoing quality control usi...
...rpretation of any ER result should include ev...
...ies should establish and follow a standard opera...
...nternal controls should be reported for cases wit...
...idated IHC is the recommended standard test fo...
...cases of newly diagnosed DCIS (without associate...
...Invasive Breast Cancer Histopathologic Concorda...
...2. Additional Recommended Reporting Comments fo...
...endations for Scoring (Readout) an...
.... Case examples to illustrate stain i...
...nd: Examples of invasive cancers w...
...Internal ControlsFigure legend: Examples of inte...
...rnal ControlsFigure legend: Optimal extern...