BREAST cancer patients with small node-negative HER2-positive tumours achieved 3-year survival approaching 100% with adjuvant paclitaxel and trastuzumab, in a recent multicentre prospective trial. This could turn the standard of care (SoC) for HER2-positive patients away from conventional chemotherapy.
Patients included in the trial had a 3-year invasive disease-free survival of 98.7%. Patients had a median age of 55 years, and 272 (67%) had HER-positive tumours. Half of the patients had tumours ≤1 cm, and 9% had tumours that were 2-3 cm at the greatest dimension. The authors reported that 356 (87.7%) patients completed the 52 weeks of therapy.
Dr Eric Winer, Director of the Breast Oncology Center, Dana-Farber Cancer Institute, Boston, Massachusetts, USA, reported that data from the trial attempted to determine whether adjuvant paclitaxel-trastuzumab could achieve a low rate of recurrence with less toxicity compared with conventional adjuvant chemotherapy regimens.
Successful safety resulted in relatively few patients with Grade 3 peripheral neuropathy, heart failure, or asymptomatic declines in left ventricular ejection fraction. “The regimen we used in this study was associated with patient outcomes that were better than expected on the basis of historical data,” Dr Winer concluded. “However, the study does not provide data to support the use of trastuzumab-based chemotherapy in all patients with small HER2-positive tumours, and there will be many patients with a T1a disease and some with T1b disease who will decide with their physicians to avoid the toxic effects of a trastuzumab-based regimen.”
Dr Winer stated that the findings may help establish a SoC for the subgroup of patients with small node-negative HER2-positive tumours. However, he also mentioned that currently no consensus exists about the most appropriate systemic therapy for the subgroup. “This study demonstrates that a combination of lower-intensity chemotherapy and trastuzumab – which is associated with fewer side-effects than traditional chemotherapy regimens – is an appealing SoC for this group of patients.”