Siddiqi, Imran N.

Abstract Background: NK/T cell non-Hodgkin lymphomas (NK/T NHL) are rare high-grade lymphomas that are diagnostically challenging and carry a poor prognosis. Incidence is notably higher in Asian countries as compared to North America and Europe. South Americans have an incidence similar to Asian countries though less well described. In this study we reviewed the incidence and outcomes of NK/T NHL in the US with a specific focus on patient race/ethnicity. Methods: Surveillance, Epidemiology and End Results (SEER) database was used to examine the standardized incidence rates (SIR) of NK/T cell NHL among adult (≥18 yrs) patients diagnosed between 1992-2013. Mutually exclusive race/ethnicity categories were: African-Americans (AA), Asians/Pacific Islanders (API), Hispanic whites (HW) and Non-Hispanic whites (NHW). Cases that received a diagnosis at death certificate/autopsy, no follow-up records, or lacking age at diagnosis, sex, or race/ethnicity documentation were excluded. Age adjusted incidence rates (AAIR) were calculated by race. Cox proportional hazards models, adjusted for confounding variables, were used to evaluate association between patient demographics and overall survival (OS). Results: A total of 706 cases met inclusion criteria. Of these, 64% were males and 36% females. AAIR was higher in males irrespective of race/ethnicity. Among different race/ethnic subgroups, API and HW had a higher AAIR than NHW and AA (0.2, 0.18, 0.05 and 0.04, respectively) (Figure 1). Median OS for males and females was similar (1.8 yr and 2 yr, respectively; p=0.76) There was a statistically significant difference in median OS by age for all patients with 4.3 yr for age 18-44 as compared with 0.8 yr for age >75 yr (p<0.001). Median OS by was different for HW (1.3 yr), API (1.8 yr), AA (2.3 yr) and HW (2.5 yr) but did not reach statistical significance (p=0.45). Median OS by stage varied as 7.3 yr for stage IE to 0.9 yr for all other stages combined (p<0.001) Cases with disease location as nasal cavity or sinus had a median OS of 3.5 yr as against 1.1 yr for those with all other sites (p<0.001) (Table 1). Conclusions: Significant disparities exist in the US for NK/T NHL incidence by race and gender, with highest AAIR among the racial minorities of API and HW, which are fastest and second fastest growing minority groups in the US respectively. Increasing age, advanced disease stage and site outside of the nasal cavity or sinus are independent predictors of poor prognosis. Some differences do exist in survival by race. These factors need to be considered for better resource allocation and utilization for this rare, often incurable and aggressive disease. Figure 1 Figure 1. Disclosures Ailawadhi: Pharmacyclics: Consultancy; Novartis: Consultancy; Amgen Inc: Consultancy; Takeda Oncology: Consultancy. Kelly:Amgen: Consultancy, Membership on an entity's Board of Directors or advisory committees; Pharmacyclics: Consultancy, Speakers Bureau; Novartis: Consultancy, Speakers Bureau.

Abstract Background: DLBCL is the most common adult NHL and despite significant advancements, outcomes in ethnic minorities remain suboptimal. Factors responsible for these disparities in ethnic minorities, especially variability in clinical and pathological features with evaluation of patient-level data have not been studied. Methods: A multi-institutional database of DLBCL patients seen at Mayo Clinic in Florida, University of Miami and University of Southern California between 1996-2016 was developed. Patient demographics, clinical disease characteristics and details of DLBCL immunophenotype [CD10, MUM1, BCL6 (Han's classification), Ki 67, MYC, BCL2) were reviewed. Comparisons between Hispanic and Non-Hispanic patients were made by Chi-square, Fischer's exact and Signed rank tests, where applicable. Patients with missing data on a certain feature were not included in the statistical analysis of that specific characteristic. Results: A total of 966 DLBCL patients with 69 Hispanics and 752 non-Hispanics were identified. These included 52% males (N=36) and 48% females (N=33) in Hispanics versus 58% males (N=436) and 42% females (N=316) in Non-Hispanics (p=0.35). Median age at diagnosis was significantly lower at 61 years (range 27-89) in Hispanics versus 66 in non-Hispanics (p=0.014). Extranodal disease was seen significantly more commonly in Hispanics (74%) than in non-Hispanics (60%) (p=0.037). There was no significant difference in disease stage at presentation between the two cohorts (p=0.189) although the proportion of patients with stage III and IV disease was higher among Hispanics (80.4%) as compared to non-Hispanics (68.5%). Similarly there was no significant difference in presence of primary CNS DLBCL at diagnosis between the two groups (p=0.74). GCB phenotype per the Hans' classification was seen in 59% (N=29) in both, Hispanics and Non-Hispanics (N=241) (p=0.99). Similarly, the median ki67 index of 80% was seen in both cohorts (p=0.48). MYC was positive in 59% in Hispanics versus only 37.5% in non-Hispanics (p=0.024). BCL2 expression by itself and also combined BCL2 and MYC double expression were not significantly different between the two groups (p=0.58 and p=0.11, respectively). Median overall survival (OS) was 22.5 months in Hispanics compared 54.9 months in Non-Hispanics (p<0.0001) (Figure 1). Conclusion: Survival outcome disparities in racial and ethnic minorities have been previously reported from population-based analyses. Lack of patient-level clinical data makes these analyses hypothesis generating, but not conclusive. We confirmed some prior findings including younger age at diagnosis for Hispanics with DLBCL. We also reported greater incidence of extranodal as well as stage III or IV disease at the time of presentation among Hispanics which may contribute to poor outcomes in this population. From DLBCL pathology standpoint, we found increased expression of MYC among Hispanics but no other significant immunohistochemical differences including double expression or non-GCB phenotype. The inferior OS despite uniform treatment practices at large Cancer Centers suggest multifactorial influences on patient outcomes which may at least in part include some of the differences we report here. Disclosures Ailawadhi: Pharmacyclics: Research Funding; Janssen: Consultancy; Takeda: Consultancy; Celgene: Consultancy; Amgen: Consultancy.