Kimbung S et al. -Pathologic complete response (pCR) is a predictor for a favorable outcome after neoadjuvant treatment in patients with early breast cancer. In the current study, the role of early transcriptional changes in predicting response to neoadjuvant chemotherapy plus bevacizumab was investigated.It was shown that changes in molecular subtypes and other signatures early in the course of neoadjuvant treatment may be predictive of pCR and event-free survival (EFS).

Methods

• 150 patients with large, operable, locally advanced HER2-negative breast cancer received epirubicin and docetaxel with bevacizumab.
• Patients underwent tumor biopsies at baseline, after cycle 2, and at the time of surgery.
• The pCR, and the relationship with EFS, OS, and gene expression profiles were determined.

Results

• The pCR rate was 13%, with significantly more pCRs among triple-negative (28%) than among hormone receptor positive (HR+) tumors (9%; OR=3.9).
• The pCR rates were not associated with EFS or OS.
• PAM50 subtypes significantly changed after cycle 2 and an index of absolute changes in PAM50 correlations between these time-points was associated with EFS (HR=0.62).
• Based on univariable analyses, signatures for angiogenesis, proliferation, estrogen receptor signaling, invasion and metastasis, and immune response, measured after cycle 2, were associated with pCR in HR+ tumors.