The longitudinal relationship between immune cell profiles and frailty in patients with breast cancer receiving chemotherapy.

BACKGROUND: Frailty is associated with an increased risk of chemotherapy toxicity. Cellular markers of inflammation can help identify patients with frailty characteristics. However, the role of cellular markers of inflammation in identifying patients at risk of developing chemotherapy-induced frailty and their clinical utility are not fully understood. METHODS: This study was a secondary analysis of a large nationwide cohort study of women with stage I-IIIC breast cancer (n = 581, mean age 53.4; range 22-81). Measures were completed pre-chemotherapy (T1), post-chemotherapy (T2), and 6 months post-chemotherapy (T3). Frailty was assessed at all three time points using a modified Fried score consisting of four self-reported measures (weakness, exhaustion, physical activity, and walking speed; 0-4, 1 point for each). Immune cell counts as well as neutrophil to lymphocyte ratio (NLR) and lymphocyte to monocyte ratio (LMR) were obtained at T1 and T2 time points. Separate linear regressions were used to evaluate the associations of (1) cell counts at T1 with frailty at T1, T2, and T3 and (2) change in cell counts (T2-T1) with frailty at T2 and T3. We controlled for relevant covariates and frailty at the T1 time point. RESULTS: From T1 to T2, the mean frailty score increased (1.3 vs 2.0; p \u3c 0.01) and returned to T1 levels by the T3 time point (1.3 vs 1.3; p = 0.85). At the T1 time point, there was a positive association between cellular markers of inflammation and frailty: WBC (β = 0.04; p \u3c 0.05), neutrophils (β = 0.04; p \u3c 0.05), and NLR (β = 0.04; p \u3c 0.01). From T1 to T2, a greater increase in cellular markers of inflammation was associated with frailty at T2 (WBC: β = 0.02, p \u3c 0.05; neutrophils: β = 0.03, p \u3c 0.05; NLR: β = 0.03; p \u3c 0.01). These associations remained significant after controlling for the receipt of growth factors with chemotherapy and the time between when laboratory data was provided and the start or end of chemotherapy. CONCLUSIONS: In patients with breast cancer undergoing chemotherapy, cellular markers of inflammation are associated with frailty. Immune cell counts may help clinicians identify patients at risk of frailty during chemotherapy. TRIAL REGISTRATION: ClinicalTrials.gov , NCT01382082