HER2 IHC Summary
Notes
**Note 1:** This SSDI is no longer required by any of the standard setters starting with 2021 diagnoses. * For cases diagnosed 2021+, this SSDI may be left blank **Note 2:** Physician statement of HER2 IHC Summary can be used to code this data item when no other information is available. **Note 3:** The HER2 IHC test performed on the primary breast tissue is to be recorded in this data item. **Note 4:** Results from nodal or metastatic tissue may be used, **ONLY** when there is no evidence of primary tumor. **Note 5:** In cases where there are invasive and in situ components and HER2 IHC is done on both, ignore the in situ results. * If HER2 IHC is positive on an in situ component and HER2 IHC is negative on all tested invasive components, code HER2 IHC as negative (code 0) * If in situ and invasive components present and HER2 IHC only done on the in situ component, code unknown (code 9) **Note 6:** In cases where there is a single tumor with multiple biopsies and/or surgical resection with different HER2 IHC results. * Use the highest (positive versus negative) **Note 7:** In cases where there are multiple tumors with different HER2 IHC results, code the results from the largest tumor size (determined either clinically or pathologically) when multiple tumors are present. * Do not use specimen size to determine the largest tumor size **Note 8:** If neoadjuvant therapy is given, record the assay from tumor specimens prior to neoadjuvant therapy. * If neoadjuvant therapy is given and there are no HER2 IHC results from pre-treatment specimens, report the findings from post-treatment specimens **Note 9:** A 2+ (equivocal) finding by IHC should result in additional testing with ISH to determine gene copy number. **Note 10:** An immunohistochemistry (IHC) test identifies the protein expressed by the gene (ERBB2), and an in situ hybridization (ISH) test identifies the number of copies of the gene (ERBB2) itself. **Note 11:** HER2 is not routinely done on pure in situ tumors (behavior /2); however, if you have an in situ tumor and there are HER2 results, go ahead and record it. Otherwise code 9.| Code | Description |
|---|---|
| 0 | Negative (Score 0) |
| 1 | Negative (Score 1+) |
| 2 | Equivocal (Score 2+) Stated as equivocal Borderline |
| 3 | Positive (Score 3+) Stated as positive |
| 4 | Stated as negative, but score not stated |
| 7 | Test ordered, results not in chart |
| 8 | Not applicable: Information not collected for this case (If this item is required by your standard setter, use of code 8 will result in an edit error.) |
| 9 | Not documented in medical record Cannot be determined (indeterminate) HER2 IHC Summary not assessed or unknown if assessed |
| <BLANK> | N/A-Diagnosis year is after 2020 |