Prognostic Nomogram for Overall Survival in Early Stage Extranodal Natural Killer/T Cell Lymphoma Treated With High-Dose Radiotherapy

The prognostic system for early stage extranodal natural killer/T-cell lymphoma, nasal-type (ENKL) treated with high-dose radiotherapy (RT) remains unclear. We developed a nomogram including 4 variables in 81 early ENKL patients treated with high-dose RT. This nomogram could predict 5-year overall survival accurately, which provides a meaningful risk estimate for early ENKL. Background: The aim of this study was to develop a prognostic nomogram for early stage extranodal natural killer/T-cell lymphoma, nasal type (ENKL) treated with high-dose radiotherapy (RT). Patients and Methods: A total of 81 patients at 2 cancer centers with stage I to IIE ENKL who received chemotherapy (CT) and high-dose RT were retrospectively analyzed. The development of the nomogram was on the basis of the Cox proportional hazards model. We implemented the concordance index (C-index) and performed a calibration curve to determine its predictive and discriminatory capacity and compared our nomogram with the International Prognostic Index (IPI) and the Korean Prognostic Index (KPI). Results: The nomogram included 4 important variables and used a multivariate analysis: lactate dehydrogenase, primary tumor invasion, tumor response, and CT regimen. The 5-year OS rate and progression-free survival were 64.7% and 57.5%, respectively for the entire group. The C-index of the nomogram for overall survival (OS) prediction was 0.87, and it was superior to the predictive power of the IPI and KPI. The calibration curve showed that the nomogram accurately predicted the 5-year OS. Conclusion: The proposed nomogram could provide an individualized risk estimate of the OS for early stage ENKL treated with CT and high-dose RT.