Neoadjuvant twelve weekly paclitaxel–carboplatin with trastuzumab and pertuzumab in HER2-positive breast cancer

PURPOSE: Standard neoadjuvant therapy for early HER2-positive breast cancer consists of 18 weeks of carboplatin, docetaxel, trastuzumab, and pertuzumab. However, treatment intensity may limit feasibility in frail patients and exceed therapeutic needs in selected early-stage disease. We report here real-world clinical outcomes of patients receiving a shortened 12-week neoadjuvant regimen of weekly paclitaxel and carboplatin administered with trastuzumab and pertuzumab (12wTCHP). METHODS: We conducted a retrospective analysis of patients with HER2-positive breast cancer treated with neoadjuvant 12wTCHP in a single tertiary medical center. RESULTS: Of forty-four eligible patients receiving 12wTCHP, 41 had invasive ductal carcinoma (IDC, 93%), and 64% were ER-positive. The majority of the cohort had stage IIA (73%, median age 59 years), while the remainder had stage IIB or stage III disease and were significantly older (median age 64 and 76 years, respectively; p = 0.007). Grade 3-4 neutropenia (20%) and diarrhea (19%) were the most frequent toxicities. No treatment-related deaths occurred. Pathological complete response (pCR) rate was 61%: 54% in ER-positive tumors and 75% in ER-negative tumors (p = 0.208). After a median follow-up of 30 months, only two recurrences (5%) were observed. None of the 30 patients with stage IIA IDC had disease recurrence. CONCLUSIONS: In this retrospective cohort study, neoadjuvant 12wTCHP was well tolerated and associated with high pCR and low early recurrence rates. These findings are hypothesis-generating and support further evaluation of de-escalated 12wTCHP regimen in selected patients.