C-Reactive Protein Pretreatment-Level Evaluation for Ewing’s Sarcoma Prognosis Assessment—A 15-Year Retrospective Single-Centre Study

SIMPLE SUMMARY: The importance of chronic inflammation in favouring a “cancer-friendly” microenvironment in most types of tumours has been analysed, except for in the case of Ewing’s sarcoma. Ewing’s sarcoma is a highly malignant blue round cell tumour that affects 2.9 in 1,000,000 children worldwide. The aim of this retrospective study was to analyse the role of C-reactive protein (CRP) as a prognostic factor. Serum CRP levels were significantly different in patients with a poorer prognosis and in patients who presented distant metastasis, whereas CRP levels were not significantly different in patients with local recurrence. In Ewing’s sarcoma cases, we believe we can consider a CRP pre-treatment value of >0.5 mg/dL as a sensitive prognostic risk factor indication for distant metastasis and poor prognosis. ABSTRACT: Background: A pathological/inflamed cellular microenvironment state is an additional risk factor for any cancer type. The importance of a chronic inflammation state in most diffuse types of tumour has already been analysed, except for in Ewing’s sarcoma. It is a highly malignant blue round cell tumour, with 90% of cases occurring in patients aged between 5 and 25 years. Worldwide, 2.9 out of 1,000,000 children per year are affected by this malignancy. The aim of this retrospective study was to analyse the role of C-reactive protein (CRP) as a prognostic factor for Ewing’s sarcomas. Methods: This retrospective study at Klinikum rechts der Isar included 82 patients with a confirmed Ewing’s sarcoma diagnosis treated between 2004 and 2019. Preoperative CRP determination was assessed in mg/dL with a normal value established as below 0.5 mg/dL. Disease-free survival time was calculated as the time between the initial diagnosis and an event such as local recurrence or metastasis. Follow-up status was described as death of disease (DOD), no evidence of disease (NED) or alive with disease (AWD). The exclusion criteria of this study included insufficient laboratory values and a lack of information regarding the follow-up status or non-oncological resection. Results: Serum CRP levels were significantly different in patients with a poorer prognosis (DOD) and in patients who presented distant metastasis (p = 0.0016 and p = 0.009, respectively), whereas CRP levels were not significantly different in patients with local recurrence (p = 0.02). The optimal breakpoint that predicted prognosis was 0.5 mg/dL, with a sensitivity of 0.76 and a specificity of 0.74 (AUC 0.81). Univariate CRP analysis level >0.5 mg/dL revealed a hazard ratio of 9.5 (95% CI 3.5–25.5). Conclusions: In Ewing’s sarcoma cases, we consider a CRP pretreatment value >0.5 mg/dL as a sensitive prognostic risk factor indication for distant metastasis and poor prognosis. Further research with more data is required to determine more sensitive cutoff levels.