Serum Biomarkers as Prognostic Factors for Metastatic Sarcoma

Abstract

AimsTo investigate the prognostic value of combining inflammatory biomarkers in a prognostic index (Aarhus composite biomarker score: ACBS), adjusted for known confounders, including comorbidity, in patients with metastatic sarcoma. Materials and methodsAll patients diagnosed with metastatic sarcoma from 1993 until 2008 were extracted from the Aarhus sarcoma database. The levels of serum albumin, C-reactive protein, serum sodium, haemoglobin, neutrophils and lymphocytes were collected. ACBS as well as the neutrophil to lymphocyte ratio (NLR), Glasgow prognostic score (GPS) and a combined score of GPS and NLR known as CNG were calculated. The prognostic importance of the biomarkers on disease-specific mortality was analysed. Adjustments were made for age, comorbidity, histological type and site of metastasis using the Cox proportional hazard model. Harrell's concordance index (C-index) was used to evaluate whether the ACBS adds prognostic information to already known prognostic factors. The data were validated using the bootstrapping method. ResultsIn total, 265 patients with metastatic sarcoma were included. The 2-year disease-specific mortality was 74% (95% confidence interval 68–80) and 79% (95% confidence interval 68–88) for soft-tissue sarcoma and bone sarcoma, respectively. Comorbidity was present in 21% of soft-tissue sarcoma patients and 13% of the bone sarcoma patients. All six biomarkers were independent prognostic factors. The various scoring systems (NLR, GPS, CNG and ACBS) combining more than one biomarker were also prognostic for disease-specific mortality. ConclusionThe biomarker scoring systems are independent prognostic factors for adult patients with metastatic sarcoma. However, a modified ACBS was superior to all the other scoring systems in predicting outcome.