Neoadjuvant Systemic Therapy in Early Breast Cancer: Results of a Prospective Observational Multicenter BRIDE Study

SIMPLE SUMMARY: To assess the percentage of early breast cancer (EBC) patients treated with neoadjuvant systemic therapy (NAT) in Italy, criteria of patient selection and types of therapies delivered, 1276 stage I-II-III patients were enrolled and evaluated in the multicenter prospective observational BRIDE study in 2018–2021. NAT was administered to 13.9% of EBC patients. In multivariate analysis, menopausal status, cT, cN, grade, HER2-positive and Triple Negative (TN) subgroups were significantly associated with the decision to administer NAT. According to phenotypic subgroup, NAT was administered to 53.2% of HER2+/HR-negative (pathologic complete response—pCR-74.2%), 27.9% of HER2+/HR+ (pCR 52.3%), 7.1% of HER2-negative/HR+ (pCR 17.2%) and 30.3% of TN (pCR 37.9%) patients. Phenotypic subgroup influenced the type of NAT delivered. Today, the use of NAT in EBC should be always considered, especially in HER2+ and TN, because of the association between pCR and better survival of patients and the current availability of effective therapies for patients with residual disease. ABSTRACT: To evaluate the rate of early breast cancer (EBC) patients treated with neoadjuvant systemic therapy (NAT) in Italy, criteria of patient selection and types of therapies delivered, an analysis of 1276 patients with stage I-II-III was conducted out of 1633 patients enrolled in the multicenter prospective observational BRIDE study. A total of 177 patients (13.9%) were treated with NAT and 1099 (85.9%) with surgery; in multivariate analysis, menopausal status, cT, cN, grade, HER2-positive and Triple negative (TN) subgroups were significantly associated with the decision to administer NAT. The type of NAT delivered was influenced by EBC subtype. NAT was administered to 53.2% of HER2+/HR-negative, 27.9% of HER2+/HR+, 7.1% of HER2-negative/HR+ and 30.3% of TN EBC patients. The pCR rates were similar to the ones reported in the literature: 74.2% in HER2+/HR-negative, 52.3% in HER2+/HR+, 17.2% in HER2-negative/HR+ and 37.9% in TN. In clinical practice, patient and tumor characteristics influenced oncologists in the decision to administer NAT in EBC and in the choice of the type of systemic therapy, according to ESMO and AIOM Guidelines. Currently, it is recommended always to evaluate the use of NAT in EBC, mainly in HER2+ and TN patients, considering that pCR is associated with significantly better survival of the patient and that effective therapies are now available for residual disease.