Prognostic Value of NCCN-IPI and Interim PET/CT Based on Visual Assessment in the Treatment of Peripheral T Cell Lymphomas
Authors: Ahn Seo-Yeon , Yhim Ho-Young , Do Young Rok , Jung Sung-Hoon , Ahn Jae-Sook , Kim Yeo-Kyeoung , Min Jung-Joon , Kwak Jae-Yong , Lee Je-Jung , Kim Hyeoung-Joon , Yang Deok-Hwan 
Published: October 2019

Abstract
Background
It has been well known that peripheral T cell lymphoma (PTCL) has undergone poor prognosis compared with other non-Hodgkin lymphomas (NHL). Although the National Comprehensive Cancer Network-International Prognostic Index (NCCN-IPI) has been proposed to determining prognosis for patients with diffuse large B-cell lymphoma (DLBCL) at 2014, there is no study examines whether NCCN-IPI could apply to the T-cell NHLs. In addition, a few studies suggest prognostic utility of interim PET/CT in PTCL, but the role of interim PET/CT is not clear.
Purpose
We evaluate the predictive efficacy of the NCCN-IPI and interim PET/CT based on visual assessment in patients with newly diagnosed PTCLs.
Methods
This study included 153 patients with de novo peripheral PTCLs, diagnosed from January 2010 to August 2015. The NCCN-IPI was calculated as following the original references. Survival outcomes were compared with a matched result of IPI and/or Prognostic Index for peripheral T cell lymphoma, unspecified (PIT). Visual assessment of interim PET/CT based on Deauville five point scales was performed at the time of diagnosis, mid-treatment and completion of CHOP/CHOP-like or other non-anthracycline chemotherapy.
Results
The subtypes of PTCLs included PTCL, not otherwise specified (PTCL-NOS) (26%), angioimmunoblastic T cell lymphoma (20%), anaplastic large cell lymphoma (13%), extranodal NK/T cell lymphoma, nasal type (35%), and the others (6%). The NCCN-IPI showed better risk-based prognostic discrimination than IPI and PIT, especially between high-intermediate and high risk subgroups (3-year overall survival 40% vs. 27% vs. 26% among the high-intermediate risk group, respectively; 3-year overall survival 15% vs. 33% vs. 32% among the high risk group, respectively) with a median follow-up of 25.1 months (Figure 1). The absolute difference of survival rates between the low and high risk groups was 75% based on the NCCN-IPI stratification compared with 45% on the IPI stratification or 54% on the PIT stratification, respectively. When divided into two histologic subgroups (nodal vs. extra-nodal type), the NCCN-IPI showed considerable discriminatory capacity in both histologic groups. However, the IPI or PIT classification could not have discrimination in extra-nodal PTCLs. The interim PET-CT was significantly predicting for progression free survival in all PTCL patients, however, it also showed no predictive value in the patients with extranodal PTCLs, especially NK/T cell lymphoma.
Conclusions
The NCCN-IPI is a powerful prognostic model in PTCLs predicting overall survival among high-intermediate and high risk patients. Also, interim PET/CT response based on visual assessment could be a valuable prediction tool in nodal PTCLs, however, it should be carefully interpreted in the treatment of extranodal subtypes.

Disclosures
No relevant conflicts of interest to declare.