Neuroendocrine Breast Tumors: Could Multigene Assays Help in Guiding Treatment Decisions? Case Presentation.

BACKGROUND/AIM: Breast cancer remains the most prevalent type of cancer among women worldwide, and it remains the primary cause of cancer-related deaths in this demographic. Neuroendocrine breast cancer (NBC), an uncommon subtype comprising less than 1% of cases, typically occurs in older women and displays as a slow-growing, low-grade condition. NBC exhibits distinct histological patterns and immunohistochemical markers. Given the limited data on NBC, assays are required that will provide information on molecular profiling and assist in clinical decision making. The aim of the study was to investigate whether a modern Multigene Assay (MGA) could assist on treatment planning of NBC patients. CASE REPORT: A cohort of four patients was analyzed using a MGA. The presented cases featured young, pre-menopausal women with clear NBC, lacking family history. All were lymph node-negative, with robust expression of neuroendocrine markers. Despite high hormone receptor expression, all tumors were poorly differentiated with elevated Ki67 levels. Oncotype DX analysis indicated a need for chemotherapy in three cases and not in one. This underscores the heterogeneity within NBC, emphasizing the importance of personalized treatment decisions. CONCLUSION: While NBC is rare and lacks extensive studies, the use of multigene assays like Oncotype DX may play a pivotal role in treatment planning, especially in cases with varying histological parameters.

Validation of the Prognostic Performance of Breast Cancer Index in Hormone Receptor-Positive Postmenopausal Breast Cancer Patients in the TEAM Trial.

PURPOSE: Patients with early-stage hormone receptor-positive (HR+) breast cancer face a prolonged risk of recurrence even after adjuvant endocrine therapy. The Breast Cancer Index (BCI) is significantly prognostic for overall (0-10 years) and late (5-10 years) distant recurrence (DR) risk in N0 and N1 patients. Here, BCI prognostic performance was evaluated in HR+ postmenopausal women from the Tamoxifen and Exemestane Adjuvant Multinational (TEAM) trial. EXPERIMENTAL DESIGN: 3,544 patients were included in the analysis (N = 1,519 N0, N = 2,025 N+). BCI risk groups were calculated using pre-specified cutoff points. Kaplan-Meier analyses and log-rank tests were used to assess the prognostic significance of BCI risk groups based on DR. Hazard ratios (HR) and confidence intervals (CI) were calculated using Cox models with and without clinical covariates. RESULTS: For overall 10-year DR, BCI was significantly prognostic in Ni0 (N = 1,196) and N1 (N = 1,234) patients who did not receive prior chemotherapy (P < 0.001). In patients who were DR-free for 5 years, 10-year late DR rates for low- and high-risk groups were 5.4% and 9.3% (N0 cohort, N = 1,285) and 4.8% and 12.2% (N1 cohort, N = 1,625) with multivariate HRs of 2.25 (95% CI, 1.30-3.88; P = 0.004) and 2.67 (95% CI, 1.53-4.63; P < 0.001), respectively. Late DR performance was substantially improved using previously optimized cutoff points, identifying BCI low-risk groups with even lower 10-year late DR rates of 3.8% and 2.7% in N0 and N1 patients, respectively. CONCLUSIONS: The TEAM trial represents the largest prognostic validation study for BCI to date and provides a more representative assessment of late DR risk to guide individualized treatment decision-making for HR+ patients with early-stage breast cancer.