Evaluation of Pathological Complete Response Rate in Patients with HER2-Positive Breast Cancer Undergoing Neoadjuvant Trastuzumab and Chemotherapy With or Without Anthracycline.

OBJECTIVE

This study aimed to evaluate the pathological complete response rate (pCR) in HER2 breast cancer by comparing anthracycline-containing and anthracycline-free regimens.

METHODS

A retrospective cohort study was performed to obtain data from women undergoing neoadjuvant chemotherapy associated with two groups: • AC-TH patients: treated with trastuzumab with confirmed HER2-positive breast cancer using an anthracycline-based therapy followed by taxane. • CTH patients: recieved trastuzumab concurrently during taxane use in an anthracycline-free regime (carboplatin plus a taxane). Clinical data, pCR, free-disease survival, and overall survival were compared using chi-square, log-rank Mantel-cox, multinomial logistic and Cox regression tests (p < 0.05, SPSS v20.0).

RESULTS

There are no differences between AC-TH and CTH in terms of: • pCR (p=0.745), •Disease- free survival (p=0.840), • Overall survival (p=0.642). The major prognostic factor for overall survival were: • Nodal metastasis (p=0.043, HR = 0.263 (CI95% = 0.072-0.959) and • Dose reduction (p=0.021, HR = 0.070 (CI95% = 0.007-0.667) and For disease-free survival: • Age (p=0.038, HR = 3.288, CI95% 1.068-10.123) and • pCR (p=0.028, HR = 0.354, CI95% = 0.140-0.895). AC-TH showed more cardiotoxicity (9.3% vs 3.4%).

CONCLUSION

Chemotherapy regimens with or without anthracycline, when combined with trastuzumab, demonstrate similar rates of pathological complete response and recurrence-free survival. Pathological complete response and age are independent variables associated with recurrence. However, the use of anthracycline leads to increased cardiotoxicity.