Chemotherapy De-escalation Strategy Under Study in Early HER2-Positive Breast Cancer
Posted: Tuesday, August 24, 2021
A phase II, multicenter, randomized trial across 45 European hospitals suggests that the neoadjuvant use of the monoclonal antibodies trastuzumab and pertuzumab appears to be a viable strategy for treating patients with early-stage HER2-positve breast cancer without chemotherapy. Antonio Llombart-Cussac, MD, of Hospital Arnau de Vilanova, Universidad Catolica Valencia, Spain, and colleagues published their findings in The Lancet Oncology.
Women with centrally confirmed, HER2-positive, stage I–IIIA, invasive, operable breast cancer with at least one breast lesion evaluable by 18F-FDG-PET were split into two study groups. Group A (71 patients) was treated with chemotherapy (docetaxel and carboplatin) in addition to trastuzumab and pertuzumab. Group B (285 patients) was treated with trastuzumab and pertuzumab with no chemotherapy. In both groups, 18F-FDG-PET scans were done before randomization and after two treatment cycles, and surgery was performed 2 to 6 weeks after the last dose of study treatment. Group A completed six cycles of treatment (every 3 weeks). Group B initially received two cycles of trastuzumab and pertuzumab. Patients who responded to treatment continued for six more cycles of treatment.
The median follow-up was 5.7 months. A majority (80%) of patients in group B responded to treatment, and 37.9% had a pathologic complete response. No deaths were reported during neoadjuvant treatment, but serious adverse events were reported in 20% of patients in group A versus 13% in group B. Global health status of patients declined (by ≥ 10%) in 65% of group A patients versus 35.5% of group B patients.
Patients with HER2-positive breast cancer may achieve a complete pathologic response and suffer fewer adverse effects when treated with neoadjuvant trastuzumab and pertuzumab without chemotherapy, concluded the study investigators. However, forthcoming 3-year invasive disease–free survival endpoint results are needed to confirm this hypothesis.
Disclosure: For full disclosures of the study authors, visit lancet.com.