Huangming Hong, He Huang, Chengcheng Guo, Xueying Li, Xiaoting Lin, Xiaohong Fu, Mengping Zhang, Shanshan Li, Xiaojie Fang, Zhao Wang

Medical Oncology, Sun Yat-sen University Cancer Center

Objective:Extranodal NK/T-cell lymphoma, nasal type (ENKL), is a rare and highly aggressive disease. The Ann Arbor staging system (ASS) failed to predict survival differences among different stages in ENKL. The aim of this study was to establish a new prognostic staging system for ENKL. Method: Patients in the cancer center of Sun Yat-sen University (1997-2006) with diagnosis of untreated ENKL were entered into a multivariate analysis to developed a new prognostic staging system (NSS): stage I: lesions confined within nasal cavity or nasopharynx without local invasiveness (paranasal sinuses or bony or skin invasion); stage II: localized disease with local invasiveness; stage III: localized disease with regional lymph node involvement (cervical lymph nodes); and stage IV: disseminated disease (lymph nodes on both sides of diaphragm, multiple extranodal site). The NSS were validated in two multicenter studies in China and an international study. Result: In the multicenter retrospective study conducted in 18 centers in China, 722 patients were analyzed. The results showed that the distribution of NSS compared with ASS from stage I to IV were 24.1%, 34.9%, 18.3%, 22.7% vs 59.1%, 19.0%, 6.9%, 15.0%, and the 5-year OS rate of stage I to IV were 56.0%, 48.3%, 33.8%, 26.1% vs 50.7%, 39.1%, 10.8%, 28.0%. For the multicenter prospective study, 233 newly diagnosed ENKL patients treated with L-asparaginase-based regimens were enrolled and also showed a balanced distribution of 17.2%, 39.9%, 19.3%, 23.6% vs 53.6%, 25.3%, 6.9%, 14.2% from stage I to IV and reasonable 5-year OS rate of 82.4%, 72.9%, 67.1%, 53.7% vs 75.2%, 65.6%, 46.9%, 73.8% from stage I to IV using the NSS compared with ASS. In the international study, 216 patients recruited from Asia Lymphoma Study Group (ALSG) showed more balanced distribution of 29.6%, 19.0%, 15.7%, 35.6% vs 48.1%, 23.1%, 3.7%, 25.0% from stage I to IV using NSS compared with ASS, the NSS also showed a better survival discrimination than ASS with the proportion of stage I to IV were 62.3%, 29.5%, 24.2%, 0.0% vs 48.5%, 28.5%, 0.3%, 0.0%. Conclusion: The new staging system for ENKL with better survival discrimination compared with Ann Arbor staging system could be useful to clinicians and for the design of clinical trials in the future.

Key Words: ENKL, New staging system