The degree of pathologic response of tumor to primary chemotherapy is
of considerable prognostic importance in patients with breast cancer.
The addition of docetaxel (Taxotere) to an anthracycline-based
primary chemotherapy regimen has been shown to result in
significantly improved pathologic breast cancer response. The
identification of predictors of treatment response will permit
cytotoxic regimens to be tailored to individual patient requirements
and permit pathologic response rates to be improved.
Estrogen-receptor (ER) status and tumor grade are known prognostic
factors for survival, although their ability to predict the response
of breast cancers to chemotherapy is uncertain. Expression of the
oncogene HER2 has been shown to predict susceptibility to doxorubicin
and resistance to cyclophosphamide (Cytoxan, Neosar). However, the
predictive value of HER2 expression in patients who receive docetaxel
The aim of this study was to identify any relationship between ER
status, tumor grade, HER2 expression, and a substantial pathologic
response in patients with breast cancer following treatment with docetaxel.
Histopathologic parameters were studied on core biopsies taken from
101 patients with breast cancer prior to receiving primary docetaxel.
Tumors were typed and graded. Immunohistochemistry was carried out
using a standard three-stage avidin biotin peroxidase complex
technique. Antigen retrieval employed microwave technology. Specific
monoclonal antibodies (with appropriate controls) were used to detect
estrogen receptors and HER2 oncoprotein. Pathologic response was
determined from operative specimens.
Univariate and multivariate analysis (UA and MVA) (logistic
regression) were used to assess the predictive power of each
variable. Univariate analysis revealed that ER negativity (P
< .001) but not HER2 positivity (P = .289) distinguished
patients with a substantial pathologic response. Multivariate
analysis suggested that only ER negativity (P = .010)
independently predicted a substantial response. High tumor grade,
tumor type, and node status did not predict a good response on UA or MVA.
CONCLUSION: Breast cancers that are estrogen-receptor negative are
more likely to achieve a near-complete or complete pathologic
response to primary docetaxel.