RESUMEN
BACKGROUND/AIM: A possible role of antibody-drug conjugates against tumors with low HER2-expression, leads to the emergence of a new "low-HER2" classification in breast cancer, encompassing tumors from the hormonal-receptor-positive and the triple-negative subgroups. There is a need for data (clinical trial data and real-world evidence) that will accurately describe this population, the risk of recurrence and the possible benefit of HER2 targeted therapies. PATIENTS AND METHODS: We retrospectively analyzed 949 patients from our Department databases, with hormonal receptor-positive and HER2-negative early breast cancer, for whom detailed data for immunohistochemical HER2-staining could be retrieved. RESULTS: HER2-low expression was detected in 66.6% of patients (472 IHC +1 and 160 IHC +2 and ISH-negative). Lobular, or mixed lobular and ductal cancers had a statistically significantly lower chance of being HER2-low when compared to pure infiltrative ductal carcinomas (53.1% vs. 69.3% respectively). HER2-low status was not prognostic for recurrence-free survival or response to neoadjuvant chemotherapy. There was a non-significant trend for increased risk of recurrence for HER2-low, compared to HER2-0, in patients with lobular or mixed lobular and ductal carcinomas (HR=2.192, 95% CI=0.819-5.912). CONCLUSION: Low expression of HER2 in hormonal receptor-positive early breast cancer does not affect prognosis but may lead to a shorter progression-free-survival in lobular and mixed ductal and lobular cancers. Despite optimal management, a large proportion of hormonal receptor-positive patients will relapse. Targeting HER2 in HER2-low cancers may offer a potential additional treatment strategy to improve survival of this group.
RESUMEN
PURPOSE: Early-stage, HER2-positive breast cancer is increasingly treated with neoadjuvant chemotherapy (NAC). After the positive results of the Neosphere trial, the standard of care has been the combination of chemotherapy with two anti-HER2 agents, trastuzumab and pertuzumab. Many oncologists use the sequence of four cycles of anthracycline-containing regimen followed by four cycles of taxane with the two monoclonals. We report here the cardiac safety of four cycles of epirubicin with cyclophosphamide followed by four cycles of docetaxel with trastuzumab and pertuzumab, given at the neoadjuvant setting in early, HER2-positive breast cancer. METHODS: We retrospectively collected data from the medical records of patients treated at our clinic between 2014 and 2020. RESULTS: It total, 55 patients treated with the same regimen were identified. There were 20 estrogen receptor (ER)-negative and 35 ER-positive patients. Complete pathologic response was observed in 64.8% of the patients. After a median cardiac follow-up of 2.61 years, and a total of 283 echocardiograms, there was only one recorded asymptomatic Left Ventricular Ejection Fraction (LVEF) fall > 25% and no symptomatic left ventricular systolic dysfunction. LVEF consistently dropped during treatment, but the drop was not significant enough to necessitate treatment interruption, and improved during follow-up. CONCLUSION: Our data confirm the effectiveness and cardiac safety of the aforementioned neoadjuvant regimen.