An inflammation-integrated prognostic nomogram for advanced-stage extranodal NK/T-cell lymphoma: a multicenter retrospective study

Extranodal natural killer/T-cell lymphoma (ENKTL) is a rare and aggressive malignancy with poor outcomes in advanced stages. Current prognostic indices fail to fully account for the heterogeneity of stage Ⅲ–Ⅳ ENKTL. We aimed to develop a nomogram integrating inflammatory and clinical parameters to improve prognostic prediction. We retrospectively analyzed 291 patients with stage III/IV ENKTL across eight hospitals for model development and 145 patients for validation. Optimal cut-off values for absolute lymphocyte count (ALC), absolute monocyte count (AMC), and lymphocyte-to-monocyte ratio (LMR) were determined. Cox regression yielded independent prognostic indicators, which were incorporated into a nomogram. The model was validated with the concordance index (C-index), receiver operating characteristic curves, area under the curve (AUC) and calibration analysis. Five factors for overall survival (OS) were identified: age > 60 years (HR: 1.749), AMC > 0.4 × 10⁹/L (HR: 1.423), LMR ≤ 1.47 (HR: 1.460), visceral organ involvement (HR: 1.979), and bone marrow involvement (HR: 1.559). These were integrated into a nomogram with a C-index of 0.644 (95% CI: 0.601–0.687). The nomogram showed better discriminatory ability compared to both the prognostic index of natural killer lymphoma (PINK) (AUC: 0.721 vs. 0.595, P = 0.0085) and nomogramrevised risk index (NRI) (AUC: 0.721 vs. 0.585, P = 0.0034). Patients were stratified into high- and low-risk groups based on median nomogram score, with the low-risk group showing significantly better OS ( High-risk vs. low-risk group, P < 0.0001) and progression-free survival (PFS) (High-risk vs. low-risk group, P < 0.0001). In the validation cohort, the C-index was 0.634 and the 3-year AUC for OS was 0.705. Both OS and PFS were significantly inferior in the high-risk group (OS: P = 0.0015; PFS: P = 0.02). We developed an inflammation-based prognostic nomogram for advanced-stage ENKTL with moderate predictive accuracy potentially aiding clinicians in individualized risk stratification. Prospective multicenter studies are warranted to further optimize and validate its clinical applicability.