Inflammatory marker cut-off points and prognosis in incurable cancer: validation study

The study aimed to determine and validate cut-off points for selected inflammatory markers to predict 30-day, 60-day and 90-day survival in patients with incurable cancer exclusively receiving palliative care.

Prospective cohort study with patients referred to the palliative care unit of a national reference centre for cancer in Brazil. The sample (n=2098) was randomised into development (n=1049) and validation (n=1049) groups. C-reactive protein (CRP), CRP/albumin ratio (CAR), neutrophil/lymphocyte ratio (NLR), platelet/lymphocyte ratio (PLR), lymphocyte/monocyte ratio (LMR), prognostic nutritional index (PNI) and systemic immune-inflammation index (SII) were evaluated. Time-dependent receiver operating characteristic curves were used to define the optimal cut-off points. Kaplan-Meier curves, Cox proportional hazards models and concordance statistic (C-statistic) were used to evaluate their predictive ability.

The optimal cut-off points related to 30-day, 60-day and 90-day mortality were, respectively, as follows: CRP ≥6.0 mg/L, ≥4.8 mg/L and ≥4.7 mg/L; CAR ≥2.0, ≥1.7 and ≥1.5; NLR ≥6.5, ≥5.8 and ≥5.7; PLR ≥298.0, ≥286.7 and ≥281.2; LMR ≥1.9, ≥2.2 and ≥2.0; PNI ≥35.5, ≥46.8 and ≥30.5; and SII ≥2254.4, ≥1983.0 and ≥1844.1. The inflammatory markers that showed discriminatory accuracy (CRP, CAR, NLR, PLR and SII) were selected for validation. These markers demonstrated predictive ability, with good discriminatory power (C-statistic ≥0.75).

Optimal cut-off points were validated for CRP, CAR, NLR, PLR and SII for use in the prognostic assessment of patients with incurable cancer exclusively receiving palliative care.