Outcome of Adolescent & Young Adult (AYA) Patients with Diffuse Large B-Cell Lymphoma (DLBCL)
Authors: Beck Jill C. , Bast Martin , Perry Deborah A. , Smith Lynette M. , Weisenburger Dennis D. 
Published: October 2019

Abstract
Abstract 1568

Introduction
Non-Hodgkin lymphoma (NHL) represents 60% of lymphoma diagnoses in children, and NHL subtypes change considerably from childhood to adulthood.[1] Recent studies have implicated age-associated biological differences in certain NHL subtypes.[2] AYAs with cancer fall between pediatric and adult patients clinically and potentially biologically. Although environmental stressors and the psychosocial transition of adolescence likely impacts these outcomes, age-related biological differences need to be better understood.
The majority of pediatric NHLs are high-grade tumors, whereas low- and intermediate-grade tumors are more common among adults.[1] Recent studies have found that young adults with NHL have poorer survival compared to children.[2] Although the incidence of AYA lymphoma has increased over the past 20 years, survival has not significantly improved, demanding a better understanding of the epidemiology and biology of lymphoma among this patient population.[3]

Methods
Cases were identified using the Nebraska Lymphoma Study Group database and chart review. All patients with DLBCL from 1983–2010 were identified (n = 1328), and 36 (2.7%) cases are included in this study of AYA DLBCL (age 13–30 years). The Kaplan-Meier method was used to estimate overall survival (OS) and event-free survival (EFS) distributions, and the log-rank test was used to compare survival distributions between groups. OS is defined as the time from the beginning of therapy to death or last follow-up. EFS is defined as the time from the beginning of therapy to progression, death, or last follow-up. P-values less than 0.05 are considered to be statistically significant. SAS software V 9.2 (SAS Institute Inc., Cary, NC) was used for all data analysis. The study was approved by the Institutional Review Board.

Results
The median age of the 36 AYA DLBCL patients was 24.2 years (range, 14.5–29.8) with a female to male ratio of 1.8:1, and 53% were primary mediastinal B-cell lymphoma. Patient characteristics are shown in table 1. Of the 36 patients, 18 have died and 18 are alive at last follow-up. Fifteen deaths were due to lymphoma, 1 treatment related, 1 unrelated to disease, and 1 of unknown cause. The 5-year EFS is 52% (95% CI 34–67%, figure 1) and OS is 58% (95% CI 49–72%). The median follow-up of patients alive at last follow-up is 8.8 years (range, 1.8 – 29). OS was not affected by gender (p=0.32), stage (p=0.43), LDH (p=0.11), B symptoms (p=0.98), or size of the largest mass at diagnosis (0.93). Nearly all patients (97%) were treated on adult chemotherapy protocols.

Discussion
This study presents data on 36 AYA patients with DLBCL. The 5-year EFS was 52% and OS was 58%. Pediatric patients report a 5-year EFS of 87–96% [2, 4] compared to adults which have a 5-year EFS of 44–80%.[4] In contrast to other reports, in this study, gender, elevated LDH, and advanced stage (III-IV) did not impact EFS or OS, although the comparisons may be under-powered due to the small sample size. Although pediatric patients have better outcomes compared to adults, AYA patients have worse EFS than both pediatric and adult DLBCL patients, demanding further understanding of the biology of AYA DLBCL and improved treatment strategies.

Disclosures:
No relevant conflicts of interest to declare.