The role of estrogen receptor beta (ER-β) in breast cancer (BC) remains unclear. Some studies have suggested that ER-β may oppose the actions of estrogen receptor alpha (ER-α), and clinical evidence has indicated that the loss of ER-β expression is associated with a poor prognosis and resistance to endocrine therapy. The objective of the present study was to determine the role of ER-β and the ER-α/ER-β ratio in predicting the response to endocrine therapy and whether different regimens have any effect on ER-β expression levels. Ninety postmenopausal patients with primary BC were recruited for a short-term double-blinded randomized prospective controlled study. To determine tumor cell proliferation, we measured the expression of Ki67 in tumor biopsy samples taken before and after 26 days of treatment with anastrozole 1 mg/day (N = 25), tamoxifen 20 mg/day (N = 24) or placebo (N = 29) of 78 participants. The pre- and post-samples were placed in tissue microarray blocks and submitted for immunohistochemical assay. Biomarker statuses (ER-β, ER-α and Ki67) were obtained by comparing each immunohistochemical evaluation of the pre- and post-surgery samples using the semi-quantitative Allred’s method. Statistical analyses were performed using an ANOVA and Spearman’s correlation coefficient tests, with significance at p ≤ 0.05. The frequency of ER-β expression did not change after treatment (p = 0.33). There were no significant changes in Ki67 levels in ER-β-negative cases (p = 0.45), but in the ER-β-positive cases, the anastrozole (p = 0.01) and tamoxifen groups (p = 0.04) presented a significant reduction in post-treatment Ki67 scores. There was a weak but positive correlation between the ER-α and ER-β expression levels. Only patients with an ER-α/ER-β expression ratio between 1 and 1.5 demonstrated significant differences in Ki67 levels after treatment with anastrozole (p = 0.005) and tamoxifen (p = 0.026). Our results provide additional data that indicate that the measurement of ER-β in BC patients may help predict tamoxifen and anastrozole responsiveness in the neoadjuvant setting. These effects of hormonal treatment appear to be dependent on the ratio of ER-α/ER-β expression. Current Controlled Trials ISRCTN89801719

Sentinel lymph node biopsy (SLNB) is the gold standard for the axillary evaluation of clinically node-negative early breast cancer. The ACOSOG Z0011 study demonstrated the safety of omitting axillary dissection for limited SLNB disease, with other trials confirming SLNB alone or with axillary radiotherapy (AR) as non-inferior. We followed PRISMA guidelines and registered at PROSPERO. Using Medline, Embase, and Cochrane, we reviewed randomized controlled trials (2010-2024). Outcomes, including 5-, 8-, and 10-year OS, DFS, recurrence rates, and lymphedema, were analyzed with R software and assessed for bias (Cochrane RoB) and evidence quality (GRADE). The focus was ALND vs. SLNB, alone or with AR, in cT1-T3 BC with 1-2 metastatic SLNs. Thirteen articles from seven randomized controlled trials (RCTs) were included, covering 7338 women with a follow-up period of 2.8-10 years. SLNB was associated with a 65 % lower risk of lymphedema than ALND, with no significant differences in the 5-, 8-, or 10-year OS, DFS, or recurrence rates. A meta-analysis comparing micrometastasis and macrometastasis showed no impact on outcomes, indicating that ALND may be unnecessary in either case. Recurrence rates also did not differ between SLNB and ALND, reinforcing SLNB's significantly lower lymphedema risk of SLNB. This systematic review and meta-analysis support SLNB as a safe and effective alternative to ALND in early-stage BC with 1-2 positive SLNs, providing comparable survival and recurrence outcomes, with fewer complications.

Trastuzumab has significantly improved the treatment of HER2-positive breast cancer, particularly in the neoadjuvant setting, where its combination with chemotherapy increases the pathologic complete response (pCR) rate. This retrospective cohort study assesses the implications of disparities in access to trastuzumab within the Brazilian public healthcare system, focusing on pCR, overall survival (OS) and disease-free survival (DFS) in non-metastatic, HER2-positive breast cancer patients undergoing neoadjuvant chemotherapy (NAC). The study was conducted in the Hospital Pérola Byington (PEROLA), a public institution, and in the Hospital do Servidor Público Estadual (HSPE), a private institution. pCR was defined as the absence of residual invasive or in situ tumors in the breast and axillary nodes. OS and DFS were calculated by Kaplan-Meier survival analysis for a 5-year period. From 2011 to 2020, 381 patients at PEROLA and 78 at HSPE underwent NAC. Trastuzumab availability was higher at HSPE (83.4 % vs. 60.0 %, p < 0.0001). Use of trastuzumab correlated with significantly higher pCR rates at both the PEROLA (54.3 % vs. 26.4 %, p < 0.0001) and the HSPE (52.7 % vs. 26.4 %, p < 0.0001). HER2-positive patients with pCR at HSPE also had better OS (80 % vs. 61 %, p < 0.0001) and DFS (89 % vs. 67 %, p < 0.0001) compared to those at PEROLA. There were significant differences in the provision of trastuzumab between the public and private healthcare systems, adversely affecting clinical outcomes and patient survival. The current data highlight the pressing need to address equity in cancer treatment to improve prognosis for every patient.

Male breast cancer accounts for 1% of all breast cancer cases, and men tend to be diagnosed at an older age than women (mean age is about 67 years). Several risk factors have been identified, such as genetic and hormonal abnormalities.