Breast cancer survival by immunohistochemistry-determined subtype: A retrospective study

Breast cancer subtype classification according to hormone receptors (HR) and human epidermal growth factor receptor 2 (HER2) using immunohistochemistry is the standard practice for therapeutic decision making. To design future studies information on characteristics and survival of each subtype is essential. We conducted a retrospective study to analyze clinical and pathologic features as well as survival data according to breast cancer immunohistochemistry subtype. There were 211 women with a RH(+)/HER2(-) breast cancer subtype, 53 HR(+)/HER2(+), 16 HER2(+) and 23 HR(-)/HER2(-), with a median overall survival in months of 39 (20.5-62.7), 42 (25.5-65), 42 (13.7-67.7) and 26 (11-78), respectively, for a 3.7 hazard ratio of death (95% Confidence Interval [CI]: 1.3-10.3) for the triple negative group as compared to the HR(+)/HER2(-) group (p = 0.01). HR positive subtypes by immunohistochemistry where most frequent and showed a greater overall survival compared to the triple negative subtype.