Key clinical point: MRI response can be used to identify patients with hormone receptor-negative (HR−), human epidermal growth factor receptor 2-positive (HER2+) breast cancer (BC) who may only require three cycles of neoadjuvant chemotherapy to achieve pathological complete response (pCR).
Major finding: After one to three cycles of chemotherapy, nearly one third of patients with HR−/HER2+ BC achieved radiological complete response (36%; 95% CI 30%-43%), of whom the majority of patients achieved pCR (88%; 95% CI 79%-94%). No treatment-related deaths were reported.
Study details: This phase 2 TRAIN-3 trial included 235 and 232 patients with stages II-III HR−/HER2+ and HR+/HER2+ BC, respectively, who received neoadjuvant chemotherapy once every 3 weeks for up to nine cycles and whose response was monitored using breast MRI after every three cycles and lymph node biopsy.
Disclosures: This study received unrestricted financial support from Roche Netherlands. Two authors declared receiving institutional research funding from or having other ties with various sources, including Roche.
Source: van der Voort A, Louis FM, van Ramshorst MS, et al, on behalf of the Dutch Breast Cancer Research Group. MRI-guided optimisation of neoadjuvant chemotherapy duration in stage II–III HER2-positive breast cancer (TRAIN-3): A multicentre, single-arm, phase 2 study. Lancet Oncol. 2024 (Apr 5). doi: 10.1016/S1470-2045(24)00104-9 Source