Perioperative Body-Composition and Phase-Angle Measures in Women Undergoing Breast Cancer Surgery After Neoadjuvant Chemotherapy or Treated Through a Surgery-First Pathway (BC-NUTRITION): Exploratory 2-Cohort Pilot Analysis.

Abstract

Background: Breast cancer survivorship requires attention to treatment-related changes in body composition, nutritional status, and quality of life. Bioelectrical impedance phase angle is influenced by tissue electrical properties and fluid distribution and may provide complementary whole-body and segmental information.

Objective: This study described perioperative body-composition and phase-angle measures in women undergoing breast cancer surgery after neoadjuvant chemotherapy or treated through a surgery-first pathway. It also estimated T0-to-T2 changes and documented the availability of selected longitudinal variables.

Methods: BC-NUTRITION (Body Composition and Nutrition Trajectories in Breast Cancer) is a prospective 2-cohort observational study with 5 planned assessments from admission to 6 months after discharge. The present exploratory pilot analysis included 30 women in cohort A, assessed after neoadjuvant chemotherapy, and 65 women in cohort B, who were treated through a surgery-first pathway. T1 measurements were displayed descriptively; inferential analyses used T0 values and participant-level T0-to-T2 changes. T0 between-cohort comparisons used Welch 2-sample t tests, within-cohort changes used paired t tests, and between-cohort differences in change used Welch tests. Benjamini-Hochberg q values were calculated across the 13 between-cohort change comparisons.

Results: All 95 participants had complete data for the 13 selected longitudinal variables at T0, T1, and T2. At T0, cohort A had lower albumin, absolute lymphocyte count, prognostic nutritional index, and whole-body 50-kHz phase angle. The whole-body phase-angle means were 4.64° (SD 0.66) and 5.23° (SD 0.62), with a difference of -0.59° (95% CI -0.88° to -0.31°; P<.001). Cohort A had a higher whole-body extracellular water to total body water ratio (ECW/TBW) than cohort B (0.3890 vs 0.3815; P<.001). Ipsilateral upper-limb 50-kHz phase angle changed by -0.50° in cohort A and -0.51° in cohort B between T0 and T2. The between-cohort difference was 0.01° (95% CI -0.17° to 0.19°; P=.93). The corresponding difference in whole-body phase-angle change was 0.14° (95% CI -0.02° to 0.30°; P=.09). No q value for the 13 between-cohort change comparisons was below 0.05.

Conclusions: The treatment pathways differed in selected laboratory and whole-body bioelectrical measures at T0. The mean upper-limb phase angle ipsilateral to the recorded tumor side decreased in both cohorts between T0 and T2. All five prespecified perioperative feasibility thresholds were met in the available T0-to-T2 data. Assessment acceptability and T3/T4 follow-up were not evaluated. Definitive interpretation requires standardized acquisition, a prechemotherapy baseline, relevant clinical covariates, and outpatient follow-up.