The Impact of Race, Age, and Sex in Chronic Lymphocytic Leukemia (CLL): A Comprehensive SEER Analysis in the Pre and Post Rituximab (R) Eras.
Authors: Nabhan Chadi , Aschebrook-Kilfoy Briseis , Evens Andrew M. , Chiu Brian C-H , Smith Sonali M. , Shanafelt Tait D. , Kay Neil E. 
Published: October 2019

Abstract
Abstract 2877

Background:
Racial disparity has been well documented in a number of cancers but the impact of race on CLL in the contemporary era is unclear. While preliminary evidence suggests that Black (B) patients (pts) have worse survival than their White (W) counterparts (Shenoy et al, Clin Lymph Myleoma Leuk, 12/2011), the importance of sex, age, socioeconomic status (SES), and whether the wide use of single use or combined therapy with R in CLL over the last decade plus has affected overall survival (OS) have not been fully explored. Further, outcome of Hispanic (H) and Asian/Pacific Islanders (A/PI) CLL pts has not been fully studied.

Methods:
We examined population based survival data from SEER 13 (1993–2008) for CLL within and across various races. We also investigated the impact of sex, age, and socioeconomic status (SES) on their clinical outcome. Outcomes were examined over two consecutive 8-year (yr) periods: Era-1 (1993–2000) and Era-2 (2001–2008) with the assumption of R therapy in CLL patients being more frequent after 2001 (market research data not shown).

Results:
We identified 24,964 pts [W =21,363 (85.5%), H =1,197 (4.7%), B =1,709 (6.8%), and A/PI =695 (2.7%)]. Differences were notable for a greater male predominance among A/PI [62% vs. 57% (B), 56% (H), 58% (W); P=0.03]; a higher proportion of pts >80 among W [22% vs. 17% (H), 15% (B), 16% (A/PI); P<0.001], and higher SES among A/PI and W pts compared to B and H (P<0.001). OS for all patients was significantly better in Era-2 vs. Era-1 at 5-yrs (65% vs. 60.4%, P<0.0001). This improvement was statistically significant in all races except A/PI pts (P=0.71) (Table). Improved survival across eras was also noted in all age groups (<50 (P<0.00001), 50–59 (P=0.007), 60–69 (P<0.0001), 70–79 (P<0.0001), >80 yrs (P<0.0001)). Further, improved OS was noted in the two SES classes evaluated (0–15% and 15.1–30% below poverty line respectively). While there were no statistical differences between males and females within either era, improvement in OS was noted in both sexes in Era-2 versus Era-1 (P<0.0001). We subsequently compared OS within and across races (Table). Despite the fact that OS improved in all races, W pts continued to have better OS in Era-2. In Era-1, while W pts had better OS than B and H pts, the OS is similar between W and A/PI. Although OS improved in all SES classes, patients with higher SES continued to have better OS in Era-2 (P<0.0001 for both).

Conclusions:
The OS of CLL pts has improved in the contemporary era for both sexes, all age groups, and all races except A/PI individuals. The improvement in outcome in Era-2 might be partially explained by increased use of R and other novel agents that became available after 2001. Despite the broad nature of these improvements, racial and SES differences in the survival persist and deserve further validation and pursuit of the causes.

Disclosures:
Shanafelt: Genentech: Research Funding; GlaxoSmith Klein: Research Funding; Teva/Cephalon: Research Funding; Celgene: Research Funding. Kay:Genentech: Research Funding; Glaxosmith Klein: Research Funding.