(P-230) Incidence and Outcomes of Mature B-cell NHL in the US Pediatric Population, 2000-2017

Background: Mature B-cell non-Hodgkin lymphoma (MB-NHL) is rare in the pediatric population ( < 18 years), and epidemiologic data are limited, especially in the younger subpopulation.

Objectives: To describe the incidence rates, clinical characteristics, and survival rates of MB-NHL in the total pediatric population as well as age subgroups within the pediatric population.

Methods: This descriptive epidemiologic study was conducted using US Surveillance, Epidemiology, and End Results (SEER) program data and SEER*Stat software.

Results: The age-adjusted annual incidence rate of MB-NHL in the pediatric population was stable (at 0.7 per 100,000) from 2000 to 2017 and much less than in the adult population (36.8 per 100,000). The most common MB-NHL subtypes in pediatrics were Burkitt lymphoma (BL) and diffuse large B-cell lymphoma (DLBCL), each with an incidence of 0.3 per 100,000. The incidence of MB-NHL in general and DLBCL in particular is much lower in younger children than adolescents (1-4 years vs. 15-18 years: MB-NHL 0.4 vs. 1.1 per 100,000; DLBCL 0.1 vs. 0.6 per 100,000). However, the incidence of BL was similar across all age groups including adults at 0.3-0.4 per 100,000. Age-adjusted incidence rates in males were approximately 1.5 (DLBCL and MB-NHL overall) to 2.5 (BL) times higher than in females in pediatrics and adults.

Among the 406,455 MB-NHL cases reported to SEER between 2000 to 2017, only 0.6% of cases occurred in children. Of these pediatric patients, 2% were < 2 years, 18% were 2-5 years, 29% were 6-11 years, and the remaining 50% were 12 to < 18 years. At diagnosis, 34% of DLBCL and 35% of BL pediatric patients presented with stage III/IV disease, 38% of DLBCL and 26% of BL had extranodal disease, and 43% of DLBCL and 53% of BL patients presented with B-symptoms.

Overall, pediatric patients with MB-NHL had better 5-year relative survival rates compared to adults (88.8% vs. 66.7%). Notably, 5-year relative survival rates for DLBCL increased with age within pediatric subgroups (75.0% [2-5y], 86.9% [6-11y], and 87.5% [12 to <18y]) whereas 5-year relative survival rates for BL decreased with age (97.9% [2-5y], 90.8% [6-11y], and 85.4% [12 to <18y]).

Conclusions: MB-NHL is rare in children of all age groups, especially in children < 2 years. This SEER data review demonstrates disparities in survival not only between pediatrics and adults, but also within pediatric subpopulations. These data also highlight the differences in the incidence of DLBCL and BL and long-term outcomes between adults and pediatric populations, and within pediatric subpopulations.