Red cell distribution width-to-albumin ratio as a prognostic indicator for giant cell tumor of bone

Giant cell tumor of bone (GCTB) is a locally aggressive, benign neoplasm with the risk of recurrence and metastasis. Cheap and reliable prognostic markers remain limited. This study aimed to evaluate the prognostic significance of routine hematologic and biochemical parameters, particularly the red cell distribution width (RDW)-to-albumin ratio and the systemic immune-inflammation index (SII), in patients with GCTB. Patients treated surgically for histologically confirmed GCTB between 2010 and 2024 were retrospectively analyzed. Preoperative laboratory data, including RDW, serum albumin, and derived indices, were reviewed. Logistic regression and receiver operating characteristic (ROC) analyses were performed to assess predictors of recurrence and metastasis. A total of 72 patients (36 women, 36 men; mean age 30.4 years) were included. During follow-up, 23.6% experienced recurrence and 20.8% developed metastasis. Patients with recurrence had significantly lower albumin (3.85 vs. 4.12 g/dL, p=0.002) and higher RDW-to-albumin ratios (3.48 vs. 3.22, p=0.005). Logistic regression identified albumin as a protective factor (OR=0.136, p=0.004) and RDW-to-albumin as an independent risk factor (OR=3.13, p=0.020). ROC analysis demonstrated moderate predictive ability for both markers (AUC 0.761 for albumin; 0.733 for RDW-to-albumin). For metastasis, RDW-to-albumin above 4.4 was associated with a twofold higher probability (AUC=0.671). Campanacci grade, tumor volume, and SII were not significantly related to outcomes. In conclusion, the RDW-to-albumin ratio showed moderate prognostic performance, comparable to other inflammation-based indices, and may serve as a simple, inexpensive adjunct for risk stratification pending external validation.