HER2 Status and Pathologic Response in Breast Cancer
Author Information
Author(s): Winer Leah MD, Ruth Karen J. MS, Bleicher Richard J. MD, Nagarathinam Rajeswari MD, McShane Melissa MD, Porpiglia Andrea S. MD, Pronovost Mary T. MD, Aggon Allison DO, Williams Austin D. MD, MSEd
Primary Institution: Fox Chase Cancer Center
Hypothesis
Does pathologic complete response (pCR) vary by HER2 immunohistochemistry (IHC) status in breast cancer patients undergoing neoadjuvant therapy?
Conclusion
HER2 IHC status predicts pCR and may help select breast cancer patients who derive the greatest benefit from neoadjuvant therapy.
Supporting Evidence
- IHC3+ patients had a higher breast pCR rate of 54% compared to 22% for IHC2+/ISH+ patients.
- Overall, breast pCR was 49% and nodal pCR was 64% across the cohort.
- Multivariable analysis showed IHC3+ status as an independent predictor of pCR.
Takeaway
This study found that patients with a certain type of breast cancer (HER2 IHC3+) are more likely to have a complete response to treatment than those with a different type (HER2 IHC2+/ISH+).
Methodology
Patients with stage I–III HER2+ breast cancer undergoing neoadjuvant therapy and surgery were identified from the National Cancer Database and stratified by IHC status.
Potential Biases
Potential biases may arise from the retrospective nature of the study and the use of a large database that may not capture all relevant clinical details.
Limitations
The study is retrospective and relies on a large cancer database, which may lack detailed treatment regimen data and other clinical variables.
Participant Demographics
The cohort included 83% IHC3+ and 17% IHC2+/ISH+ patients, with a median age of 53 years.
Statistical Information
P-Value
p<0.0001
Confidence Interval
CI 3.65–4.19
Statistical Significance
p<0.0001
Digital Object Identifier (DOI)
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