HALP score in solid tumors: Prognostic value, heterogeneity, and translational considerations

The hemoglobin, albumin, lymphocyte, and platelet (HALP) score is an accessible composite biomarker integrating nutritional reserve, immune competence, and systemic inflammatory status. Increasing evidence indicates that a lower HALP score is generally associated with inferior survival outcomes across multiple solid tumors. In this review, we summarize current clinical evidence regarding the prognostic value of HALP, with a focus on lung, breast, gastric, and colorectal cancers, and briefly discuss its potential applications in other malignancies and non-cancer settings. Importantly, we highlight major sources of methodological heterogeneity-including sampling timing, endpoint selection, treatment context, multivariable adjustment strategies, and data-driven cutoff derivation-that contribute to inconsistent thresholds and variable effect estimates across studies. We further provide practical considerations to improve reproducibility and transportability, including prespecified sampling windows, transparent reporting of cutoff derivation methods, prioritization of continuous-variable modeling, and external validation in independent cohorts. However, most current evidence remains retrospective, single-center, methodologically heterogeneous, and based on non-standardized cutoffs. Therefore, HALP should currently be interpreted as a hypothesis-generating and adjunctive marker for host-related risk stratification rather than a validated standalone tool for routine clinical decision-making. Prospective multicenter validation, standardized sampling procedures, externally validated thresholds, and demonstration of incremental prognostic value beyond established clinicopathological and biomarker-based models are required before routine clinical implementation.