3410 - Tumor Response to Induction Chemotherapy Followed by Radiotherapy, Chemotherapy Intensity, and Patients with Early-Stage Extranodal Natural Killer/T Cell Lymphoma

H. Luo; chongqing university cancer hospital, chongqing, China

Purpose/Objective(s): Chemoradiotherapy is the main treatment strategy for extranodal natural killer/T cell lymphoma (ENKL). However, whether CT intensity can be safely reduced for patients exhibiting a satisfactory tumor response after induction chemotherapy (CT) followed by radiotherapy (RT), remains unclear. Materials/

Methods: A total of 74 patients with stage I to IIE ENKL who received induction CT followed by RT as primary treatment were enrolled.
Results: Thirty-four patients received low-intensity CT, which was defined as receiving = 3 cycles CT and 40 patients received high-intensity CT with more than 4 cycles CT. The tumor response after RT was a complete response (CR) for 51.4%, and partial response (PR) for 36.5%. Multivariate analysis revealed that CR and PR were favorable prognostic factors for 3-year overall survival (OS) (hazard ratio [HR], 18.032; 95% confidence interval [95% CI], 5.361-60.653 [P=0.000]) and 3-year progression-free survival (PFS) (HR, 13.833; 95% CI, 4.334-44.148 [P=0.000]) compared with stable disease (SD). Regarding the patients with CR and PR, no significant differences were observed between low-intensity CT group and high-intensity CT group in the univariate analysis of 3-year OS (70.9% vs. 81.7%; P=0.350) and 3-year PFS rates (67.4% vs. 82.1%; P=0.249), which were confirmed by multivariate analysis.
Conclusion: This study revealed that CT intensity could be safely reduced and that the tumor response maybe a prognostic predictor and help in the development of individualized treatment strategies for early-stage NK/T lymphoma.