Combination of local tumor invasiveness (LTI) and International Prognostic Index (IPI) provides better predictive value in extranodal NK/T-cell lymphoma, nasal type (NTCL)

Abstract

17503 Background: In contrast to B-cell lymphomas, NK/T-cell lymphomas have unique clinical pattern (local invasiveness; Blood. 2005;106:3785). Prognostic factors were evaluated according to IPI as well as LTI and compared with the other prognostic model (Lee J, et al JCO 2006). Methods: 176 patients diagnosed with NTCL between 1992 and 2004 were analyzed. Overall survival (OS) and progression-free survival (PFS) were compared according to IPI, IPI combined with LTI, and the other model. LTI was briefly defined as follows: bony invasion or perforation or skin invasion (upper aerodigestive tract); serosal invasion or perforation (gastrointestinal tract); tumor more than 5cm or invasion of deep extradermal structures (skin); and neurovascular or bony invasion (muscle). Results: After a median follow-up period of 80 months, 5-year (y) OS and PFS were 33% and 25%, respectively. The IPI risk group was predictive of OS and PFS (5-y OS 52%, 23%, 10%, and 4%, respectively, P < .0001; 2-y PFS 47%, 31%, 5%, and 4%, respectively, P < .0001) but failed to show survival differences between the high-intermediate and high risk groups (P = .0737). However, once both IPI and LTI are combined, there were significant differences in OS and PFS between the IPI score 0–2/LTI-, IPI score 0–2/LTI+, IPI score 3–5/LTI-, and IPI score 3–5/LTI+ groups (5-y OS 60%, 14%, 7%, and 4%, respectively, P < .0001; 2-y PFS 53%, 21%, 9%, and 4%, respectively, P < .0001). OS and PFS were also affected by the other prognostic model but this model failed to show survival differences among the risk groups (P = .1382). Conclusions: Combination of local tumor invasiveness and International Prognostic Index provides better predictive value in extranodal NK/T-cell lymphoma, nasal type. No significant financial relationships to disclose.