Abstract
Objective Four breast cancer subtypes defined by immunohistochemistry (IHC) expression of estrogen receptor (ER) or progesterone receptor (PR) and human epidermal growth factor receptor 2 (Her2) are ER/PR+,Her2+; ER/PR+,Her2−; ER/PR−,Her2+; and ER/PR−,Her2−.
Methods A 7-year retrospective study of 1134 invasive breast cancer subjects. Clinical and pathologic features and survival of the four subtypes were compared.
Results Using ER/PR+ and Her2− as a reference, ER/PR−,Her2− had worst overall survival (hazard ratio, 1.8; 95% confidence interval [CI], 1.06–3.2), and worst disease-free survival (hazard ratio, 1.5; 95% CI, 0.8–3.0). In ER/PR+,Her2−, chemotherapy conferred significant overall and disease-free survival advantages. Subtype comparison revealed statistically significant differences in outcomes.
Conclusion Triple negative subtype having worst overall and disease free survival. Efforts should be directed at standardization of current testing methods and development of more reliable and reproducible testing.
- Breast cancer subtype
- breast cancer survival
- breast cancer treatment
- estrogen/progesterone receptor
- human epidermal growth factor receptor 2 (HER2/neu)
- immunohistochemistry
- triple negative
- Received October 3, 2008.
- Revision received November 21, 2008.
- Revision received January 19, 2009.
- Accepted February 6, 2009.
