Interim PET Evaluation By Deauville Criteria Is an Effective Risk Stratification Tool in PTCL
Authors: Mehta-Shah Neha , Ito Kimiteru , Bantilan Kurt S , Moskowitz Alison J , Sauter Craig S , Horwitz Steven M , Schoder Heiko 
Published: October 2019

Abstract
Background: Peripheral T-cell lymphomas (PTCL) are a heterogeneous group of aggressive non-Hodgkin lymphomas. The most commonly used initial treatment is CHOP-based chemotherapy often followed by consolidation with an autologous transplant. 18-fluorodeoxyglucose positron emission tomography (PET) imaging is often used to evaluate response to therapy. While the international prognostic index (IPI) and Prognostic Index for T-cell Lymphoma (PIT) can help risk stratify patients, little data exists regarding the use of interim PET using the 5-point Deauville criteria in PTCL.
Methods: We retrospectively identified patients with PTCL-not otherwise specified (PTCL-NOS),angioimmunoblastic T-cell lymphoma (AITL), andAlk-negative anaplastic large cell lymphoma (ALK- ALCL) in the Memorial Sloan Kettering Cancer Center (MSKCC) database who were initially treated with CHOP based therapy and had PET imaging between 2001 and 2015 and had at least 6 months follow up, or an event of progression or death. Baseline, interim and end of treatment PET scans werere-read for this study using the Deauville score. Data regarding disease characteristics, relapse and survival status were collected. Event free survival (EFS) and overall survival (OS) were estimated by Kaplan-Meier method, and compared by the log rank test.
Results: 112 patients were identified with PTCL-NOS (n=40), AITL (n=49),ALK- ALCL (n=23) in the MSKCC database. Of these, 99 patients had interim PET images for review and 90 had PET images following cycle 6. The median estimated OS and EFS for the series was 93 months and 35 months respectively with a median follow up of 45 months. When evaluated by the Deauville criteria, patients with an interim PET with a score of 1-3 (n=83) had a median OS and EFS of 104 months and 64 months compared to those with a score of 4-5 (n=16) who had a median OS and EFS of 19 and 11 months (p<0.001).
In this cohort, patients with baseline PIT score²1 (n=61) had a median EFS of 64 months compared to those with a score of >1 (n=51) who had a median EFS 24 months (p=0.019). Interim Deauville score more accurately identified patients at risk for poor outcome compared to baseline PIT score alone (p<0.001). (Figure 1A and 1B)
In this cohort, patients with baseline IPI score²3 (n=90) had a median OS and EFS of 104 and 38 months compared to those with a score of >3 (n=22) who had a median OS and EFS of 51 and 13 months (p<0.05). Furthermore, interim Deauville further risk stratified patients compared to baseline IPI (p<0.001).
Conclusion: Interim PET when evaluated by the 5-point Deauville criteria carries prognostic value in PTCL. In this cohort, interim PET more accurately identified patients at risk of poor outcome compared to baseline IPI and PIT.

Disclosures
Moskowitz: BMS: Consultancy; Seattle Genetics: Consultancy, Research Funding. Horwitz:Seattle Genetics: Consultancy, Research Funding; Huya: Consultancy; ADCT Therapeutics: Research Funding; Bristol-Myers Squibb: Consultancy; Infinity: Consultancy, Research Funding; Takeda: Consultancy, Research Funding; Kyowa Hakka Kirin: Consultancy, Research Funding; Celgene: Consultancy; Spectrum: Consultancy, Research Funding.