Interleukin-6 in relation to early recurrence in primary, localized soft tissue sarcoma: An addition for existing risk classification systems?

Background: Several inflammatory markers have gained interest as prognostic factors for cancer. The aim of this study is to evaluate the inflammatory markers interleukin-6 (IL-6), C-reactive protein (CRP), neutrophil-to-lymphocyte ratio (NLR) and platelet-to-lymphocyte ratio (PLR) as predictive markers for aggressive behavior and early recurrences in primary, localized soft tissue sarcoma (STS). Methods: 115 STS patients were retrospectively reviewed. IL-6 and CRP blood levels, NLR and PLR were obtained prior to treatment. Early recurrence was defined as disease relapse (local or distant) within the first year after surgery. Cox regression analysis was used to identify prognostic factors for early recurrence. Results: IL-6 elevation was associated with a higher tumor grade, increased size, tumor necrosis and a higher mitotic count. NLR elevation was associated with a higher tumor grade, PLR elevation with a larger tumor size. Early recurrences were found in 24 patients (21 %). Univariable analysis revealed that tumor grade (p = 0.029), tumor size (p = 0.030, >10 cm vs < 5 cm), tumor depth (p = 0.036), necrosis on imaging (p = 0.008), mitotic count (p = 0.045, ≥20 mitoses vs 0–9 mitoses), and IL-6 level (p = 0.044) were associated with early recurrence. The factors age at diagnosis, tumor location, necrosis at pathology, (neo)adjuvant radio- or chemotherapy, resection margin, CRP level, NLR and PLR were not related to early disease recurrence. Conclusions: Increased inflammatory markers in STS are associated with an aggressive phenotype. STS patients with elevation of IL-6 may be at risk for early disease recurrence.