Pretreatment Body Composition Parameters and HALP Score in Relation to Pathological Complete Response in HER2-Positive Breast Cancer Receiving Neoadjuvant Systemic Therapy

Background/Objectives: Pathological complete response (pCR) is an important early endpoint in HER2-positive breast cancer treated with neoadjuvant therapy. Although tumor biology is a major determinant of response, the potential contribution of host-related factors such as body composition and systemic inflammatory-nutritional status remains uncertain. This study evaluated the associations of pretreatment skeletal muscle index (SMI), myosteatosis, an imaging-defined low-SMI obesity phenotype, and hemoglobin-albumin-lymphocyte-platelet (HALP) score with pCR.

Methods

This retrospective single-center study included 114 patients with HER2-positive disease documented on pretreatment biopsy who received neoadjuvant systemic therapy followed by definitive surgery. CT-based body-composition measurements at the L3 level were available in 88 patients. SMI, skeletal muscle radiodensity, myosteatosis, an imaging-defined low-SMI obesity phenotype, and pretreatment HALP score were assessed. Factors associated with pCR were evaluated using Firth penalized logistic regression. Two multivariable models incorporated body-composition variables, HALP, hormone receptor status, simplified clinical T and N categories, HER2-treatment group, age, and Ki-67. Final multivariable analyses included 80 complete cases.