Analysis of the pathologic response to primary chemotherapy in patients with locally advanced breast cancer grouped according to estrogen receptor, progesterone receptor, and HER2 status.

Purpose: In clinical practice, it is possible to classify breast tumors according to estrogen receptor (ER), progesterone receptor (PgR), and HER2 overexpression: ER negative, PgR negative, and HER2 overexpressing; ER negative, PgR negative, and HER2 negative; ER positive, PgR positive, and HER2 negative; ER positive, PgR positive, and HER2 overexpressing; and the less frequent remaining 4 combinations. The aim of this study was to determine the percentage of pathologic complete response (pCR) in patients with locally advanced breast cancer (LABC) treated with neoadjuvant or primary chemotherapy with anthracyclines and taxanes grouped according to ER, PgR, and HER2 status.

Patients And Methods: Patients with LABC treated with primary chemotherapy including anthracyclines and taxanes were grouped according to ER, PgR, and HER2 status; pCR rates were analyzed using the chi(2) test; and correlations with a P value of < or = 0.05 were considered statistically significant.

Results: A total of 103 patients were treated. Only 100 patients were included for the analysis of pCR. Eighteen patients exhibited pCR. The pCR rate for each subgroup was as follows: 39.1% (9 of 23) had ER-negative, PgR-negative, and HER2-negative disease (P < 0.01); 35.7% (5 of 14) had ER-negative, PgR-negative, and HER2-overexpressing disease; 33.3% (3 of 9) had ER-positive, PgR-positive, and HER2-overexpressing disease; and 2.8% (1 of 36) had ER-positive, PgR-positive, and HER2-negative disease (P < 0.01).

Conclusion: In patients with LABC, grouping breast tumors according to ER, PgR, and HER2 status can help predict pCR to primary chemotherapy.