Influence of HER2 expression on prognosis in metastatic triple-negative breast cancer-results from an international, multicenter analysis coordinated by the AGMT Study Group.

BACKGROUND: Triple-negative breast cancer (TNBC) is associated with poor prognosis, and new treatment options are urgently needed. About 34%-39% of primary TNBCs show a low expression of human epidermal growth factor receptor 2 (HER2-low), which is a target for new anti-HER2 drugs. However, little is known about the frequency and the prognostic value of HER2-low in metastatic TNBC. PATIENTS AND METHODS: We retrospectively included patients with TNBC from five European countries for this international, multicenter analysis. Triple-negativity had to be shown in a metastatic site or in the primary breast tumor diagnosed simultaneously or within 3 years before metastatic disease. HER2-low was defined as immunohistochemically (IHC) 1+ or 2+ without ERBB2 gene amplification. Survival probabilities were calculated by the Kaplan-Meier method, and multivariable hazard ratios (HRs) were estimated by Cox regression models. RESULTS: In total, 691 patients, diagnosed between January 2006 and February 2021, were assessable. The incidence of HER2-low was 32.0% [95% confidence interval (CI) 28.5% to 35.5%], with similar proportions in metastases (n = 265; 29.8%) and primary tumors (n = 425; 33.4%; P = 0.324). The median overall survival (OS) in HER2-low and HER2-0 TNBC was 18.6 and 16.1 months, respectively (HR 1.00; 95% CI 0.83-1.19; P = 0.969). Similarly, in multivariable analysis, HER2-low had no significant impact on OS (HR 0.95; 95% CI 0.79-1.13; P = 0.545). No difference in prognosis was observed between HER2 IHC 0/1+ and IHC 2+ tumors (HR 0.89; 95% CI 0.69-1.17; P = 0.414). CONCLUSIONS: In this large international dataset of metastatic TNBC, the frequency of HER2-low was 32.0%. Neither in univariable nor in multivariable analysis HER2-low showed any influence on OS.

Breast cancer in very young women-a multicenter 10-year experience.

BACKGROUND: Breast cancer (BC) is the most prevalent cancer in adult young women in Europe. Although rare, it is one of the leading causes of death in this age group. The aim of this study is to characterize a cohort of young women regarding tumor stage, biology, treatment and survival. PATIENTS AND METHODS: We present a multicenter retrospective analysis of women <35 years of age, diagnosed with BC between 2008 and 2017. A total of 207 patients from five Portuguese centers were included, from whom 172 were eligible for analysis. Data were analyzed using IBM SPPSS statistics. RESULTS: Median age at diagnosis was 31 years. Fifty-one percent of tumors were hormone receptor (HR)-positive/human epidermal growth factor receptor 2 (HER2)-negative, 20% HR-positive/HER2-positive, 8% HR-negative/HER2-positive and 20% triple-negative BC. Twenty-two percent of patients were diagnosed in stage I, 26% stage II, 45% stage III and 6% had de novo metastatic cancer. Thirty-nine percent of patients were treated with neoadjuvant chemotherapy. Mean follow-up time was 64.9 months and overall survival at 5 years, of the entire cohort and metastatic patients, was 86.5% and 26%, respectively. CONCLUSIONS: In our study we found similar population characteristics to other cohorts <35 years of age. To our knowledge, this is one of the largest cohorts in very young women. BC in young women is an important issue and further studies are needed to provide better care and survivorship to patients.