CLO26-131: Hematologic-IHC Prognostic Score for Therapeutic Prioritization in Breast Cancer: Multicenter Validation in Peru (2010-2020)

Abstract

Introduction: Early treatment selection in breast cancer is often delayed in Latin America due to limited access to advanced biomarkers. We propose an accessible score based on baseline complete blood count and standard immunohistochemistry (IHC) to stratify risk at first consultation. Objective: To internally develop and validate a hematologic–IHC prognostic score to estimate 5-year overall survival. Methods: Multicenter retrospective cohort across four public hospitals in Lima-Peru (2010–2020). A total of 883 patients with histologic confirmation, baseline blood counts and complete IHC (ER, PR, HER2, Ki-67) were included. The Hematologic–IHC Prognostic Score (SPHIQ) integrates six routinely available clinicopathologic and hematologic parameters, yielding a total score ranging from 0 to 12 points: PIV: <250 (0), 250–399 (1), ≥400 (2); PLR: <150 (0), 150–199 (1), ≥200 (2); Hemoglobin (g/dL): >12 (0), 11–12 (1), ≤11 (2); Stage: I–II (0), III (1), IV (2); Histologic grade: G1 (0), G2 (1), G3 (2); Molecular subtype: Luminal A (0), Luminal B (1), HER2+/HR- or TNBC (2). The cumulative SPHIQ score reflects tumor biological aggressiveness, where higher scores correlate with poorer prognosis. This integrated index enables early pre-consultation risk stratification by combining systemic inflammation, hematologic status, and molecular subtype into a single, reproducible prognostic tool. Risk groups: low 0–4, intermediate 5–8, high 9–12. Statistics: Kaplan–Meier, log-rank, multivariate Cox, bootstrap, AUC and C-index. Results: Risk distribution: low n=290 (32.8%), intermediate n=394 (44.6%), high n=199 (22.5%). 5-year OS: 83%, 61% and 34% (log-rank p<0.001). Independent predictors of lower OS: * PIV≥310 aHR 4.94 (95%CI 1.59–15.38; p=0.006) * PLR≥150 aHR 2.33 (95%CI 1.22–4.44; p<0.05) * Triple-negative and HER2+ HR-negative with worst prognosis Model performance: C-index 0.72, AUC 0.71. Calculation time: <5 minutes in clinic. Conclusion: SPHIQ enables immediate prognostic stratification using standard CBC and IHC, optimizing therapeutic prioritization and resource allocation in Latin American healthcare systems.