Citations

e16334 Background: Liver cancer remains a leading cause of cancer-related mortality in the United States. Although overall mortality has increased over the past two decades, age-specific patterns and demographic disparities are not fully characterized. Here, we analyzed U.S. liver cancer mortality trends from 1999 to 2023, with a focus on age-related, racial and ethnic, and geographic differences. Methods: Mortality data for U.S. adults aged ≥25 years from 1999 to 2023 were obtained from the CDC WONDER database (ICD-10 codes C22.0–C22.9). Age-adjusted mortality rates (AAMRs) were standardized to the 2000 U.S. population. Joinpoint regression was used to estimate annual percent change (APC) and average annual percent change (AAPC) across age groups, sex, race/ethnicity, U.S. census regions, and levels of urbanization. Results: From 1999 to 2023, overall liver cancer AAMRs increased from 6.95 to 10.1 per 100,000. Marked age-specific differences were observed. Mortality among adults aged 45–54 and 55–64 years peaked in the mid-2010s and subsequently experienced significant declines through 2023 (recent APCs < −4.5% for both groups; P < 0.001). Specifically, while the overall AAPC for the 55–64 age group was +1.89%, mortality significantly reversed after 2016 (APC, −4.59%). In contrast, mortality continued to rise among older adults, including those aged 65–74 years (AAPC, +2.26%), 75–84 years (AAPC, +1.69%), and aged ≥85 years (AAPC, +1.77%) (all P < 0.001). Differences in mortality trends were also identified across racial and ethnic groups. Sustained increases were observed among Non-Hispanic White individuals (AAPC, +1.89%; P < 0.001), while Hispanic/Latino populations experienced declines after 2013 (APC, −0.67%; P = 0.003). Non-Hispanic Black individuals demonstrated a significant decrease in mortality between 2017 and 2020 (APC, −3.82%; P = 0.03). Regionally, liver cancer mortality declined in the Northeast after 2013 (APC, −0.66%; P < 0.001), whereas no significant post-peak declines were observed in the South or West. Conclusions: U.S. liver cancer mortality trends exhibit substantial heterogeneity by age, race and ethnicity, and geographic region. The recent, sharp declines among middle-aged adults (APCs < −4.5%) likely reflect the success of large-scale viral hepatitis screenings and highly effective antiviral therapies, whereas continued increases among older adults may relate to the cumulative impact of metabolic risk factors and delayed diagnosis. Persistent racial and regional disparities highlight the need for targeted, age-specific prevention and surveillance strategies.

e16322 Background: Small intestine neuroendocrine carcinoma (NEC) is a rare, aggressive malignancy comprising less than 0.1% of gastrointestinal cancers. Population-level data remain limited, restricting understanding of long-term survival patterns, demographic disparities, and evolving disease burden. We evaluated survival outcomes, demographic predictors, and incidence trends of small intestine NEC in the United States. Methods: We conducted a retrospective population-based cohort study using SEER Research Data (17 registries, November 2024 submission). Patients diagnosed with malignant small intestine NEC (ICD-O-3 morphology code 9.3.3.1.2) between 2000 and 2022 were identified using SEER*Stat (v9.0.4.2). Variables including age group, sex, race, year of diagnosis, survival time, and vital status were analyzed in R (v4.5.1). Overall survival (OS) was estimated using Kaplan–Meier methods and compared using log-rank testing. Cox proportional hazards models identified independent predictors of OS. Annual case counts were modeled using time-series forecasting to project future incidence. Results: A total of 506 patients were included. Estimated OS was 94.4% (95% CI 92.4–96.4) at 1 year, 88.1% (85.3–91.0) at 3 years, and 82.4% (79.0–85.9) at 5 years, with a subset demonstrating survival beyond 15 years. Increasing age was associated with worse survival (log-rank p = 0.058). Significant racial differences in OS were observed (log-rank p < 0.0001). In multivariable analysis, race remained independently associated with OS. Incidence forecasting projected a modest increase in annual case burden over the next decade. Conclusions: Small intestine NEC demonstrates heterogeneous survival outcomes, significant demographic disparities, and projected growth in disease burden. These findings highlight the need for improved risk stratification, equitable access to care, and integration of molecular and treatment-level data to optimize management of this rare malignancy

e16229 Background: Liver cancer is a leading cause of cancer-related mortality worldwide, with rising incidence linked to metabolic disorders. Conditions such as obesity, diabetes mellitus, and metabolic syndrome contribute substantially to non-viral liver carcinogenesis. However, long-term temporal trends and mortality disparities among adults with metabolic disorders in the United States remain incompletely characterized. Methods: Mortality data for liver cancer among adults with metabolic disorders were obtained from the centers for disease control and prevention (CDC) mortality database. Adults aged 25 years and older were included and age-adjusted mortality rates (AAMRs) per 100,000 were calculated. Temporal trends were evaluated using joinpoint regression and average annual percent change (AAPC) with 95% confidence intervals. Results: From 1999–2023, AAMR for liver cancer in adults with metabolic disorders rose from 0.17 to 0.65 per 100,000 in the U.S., with an overall AAPC of 5.95% [95% CI 5.2–6.7]. Men had higher absolute mortality (0.25→0.93; AAPC 5.68%), while women showed a sharper recent rise (0.11→0.41; AAPC 7.08%), peaking at 11.86% annually after 2016. Hispanic/Latino (0.27→0.89; AAPC 6.73%) and Black populations (0.15→0.75; AAPC 6.15%) experienced steady increases, whereas White mortality accelerated post-2011 (AAPC 9.37%). Regionally, the West had highest rates, the South showed highest growth, and Northeast/Midwest had sharp recent increases. Rural mortality overtook urban by 2020 (0.50 vs. 0.48). Most deaths occurred in medical facilities (48.2%) or home (33.1%), with highest state rates in Hawaii (0.56), Texas (0.47), and Rhode Island (0.47). Conclusions: Mortality from liver cancer in adults with metabolic disorders rose sharply in the U.S. since 1999, with accelerating trends and marked disparities by sex, race/ethnicity, region, and urbanization. These findings highlight an urgent need for targeted metabolic risk reduction and equity-focused prevention strategies. Trends in Age-Adjusted Mortality Rates (AAMR) from 1999 to 2023 by demographic and geographic variables. Variable AAMR 1999 (per 100,000) AAMR 2023 (per 100,000) AAPC (95% CI) Overall 0.16 0.64 5.94* (5.22 – 6.67) Males 0.25 0.92 5.67* (4.82 – 6.5) Females 0.11 0.40 7.08* (5.79 – 8.38) White 0.16 0.63 6.12* (5.41 – 6.82) Black 0.15 0.75 6.15* (5.11 – 7.19) Hispanic or Latino 0.27 0.89 6.73* (5.98 – 7.48) Variable AAMR 1999 (per 100,000) AAMR 2020 (per 100,000) AAPC (95% CI) Urban 0.16 0.47 5.38* (4.43 – 6.33) Rural 0.19 0.50 5.73* (4.48 – 6.99) AAPC denotes the average annual percent change; * indicates p < 0.05.

e16157 Background: Liver cancer mortality remains a major public health burden in the United States despite advances in prevention and treatment. Psychoactive substance use disorder (PSUD) is an increasingly prevalent comorbidity; however, national trends and disparities in liver cancer mortality among adults with PSUD remain poorly characterized. Methods: We conducted a retrospective analysis of liver cancer-related deaths among U.S. adults aged 25 years and older with PSUD from 1999 to 2023 using Centers of Disease Control (CDC) Wide Ranging Online Data for Epidemiological Research (WONDER) mortality database. Age-adjusted mortality rates (AAMRs) were calculated per 100,000 population and stratified by census region, state, urban–rural status, sex, and race/ethnicity. Temporal trends were assessed using Joinpoint regression to estimate average annual percent change (AAPC). Statistical significance was determined using p-value (<0.05). Results: Overall liver cancer related AAMR per 100,000 among adults with PSUD significantly increased from 0.15 in 1999 to 1.02 in 2023 (AAPC: 7.47; 95% CI: 6.33 to 8.61; p < 0.000001). The overall mortality burden was higher in males. However, females experienced larger rises in mortality (AAPC: 10.03; 95% CI: 8.85 to 11.24; p < 0.000001) as compared to males (AAPC: 7.30; 95% CI: 5.78 to 8.84; p < 0.000001). Marked racial disparities were observed, with non-Hispanic Black and non-Hispanic White individuals experiencing the highest mortality rates with persistent increases over time, while Hispanic/Latino populations exhibited modest and variable trends. A substantial geographic variability was observed, with the greatest increases in the Midwest and the South. State-level analysis revealed higher mortality rate in Oregon (1.27) followed by Washington (1.12) and Texas (1.06) respectively. Both rural and urban areas experienced a sharp rise in mortality with AAPC being slightly higher in rural areas (AAPC: 10.34) as compared to urban areas (AAPC: 9.67). Conclusions: Liver cancer mortality among U.S. adults with PSUD has risen markedly over the past two decades, with substantial demographic and geographic disparities. These findings highlight the need for integrated liver cancer screening and substance use disorder interventions targeting high-risk populations. Variables AAMR (95% CI) in 2023 AAPC (95% CI) Overall 1.02 (0.98 –1.05) 1999-2023: 7.47* (6.33 – 8.61) Female 0.42 (0.39 – 0.46) 1999-2023: 10.03* (8.85 – 11.24) Men 1.69 (1.62 –1.76) 1999-2023: 7.30* (5.78 – 8.84) White 1.05 (1.0 –1.09) 1999-2023: 9.52* (8.08 – 10.98) Black / African Americans 1.22 (1.09 – 1.35) 1999-2023: 6.59* (5.50 – 7.68) Hispanics / Latinos 0.75 (0.65 – 0.84) 1999-2023: 1.26 (-1.01 – 3.60) AAMR (95% CI) in 2020 AAPC (95% CI) Rural 1.51 (1.39 – 1.62) 1999-2020: 10.34* (5.05 – 15.90) Urban 0.92 (0.82 – 0.95) 1999-2020: 9.67* (7.32 – 12.06)

e16102 Background: Esophageal cancer remains a significant cause of cancer mortality in the United States. While overall trends have been reported, less is known regarding contemporary long-term patterns and specific disparities across demographic and geographic strata. We aimed to characterize esophageal cancer mortality trajectories and identify populations with divergent outcomes by age, race/ethnicity, geographic region, and urbanization status. Methods: We analyzed esophageal cancer mortality data from 1999 to 2023 using the Centers for Disease Control and Prevention (CDC) WONDER database. Age-adjusted mortality rates (AAMRs) were standardized to the 2000 U.S. standard population. Joinpoint regression analysis was utilized to estimate the annual percent change (APC) and average annual percent change (AAPC) with 95% confidence intervals (CIs). Analyses were stratified by age, sex, race/ethnicity, census region, state, and urbanization level. Results: Overall esophageal cancer mortality in the U.S. declined significantly from 1999 to 2023 (AAPC, -0.81%; 95% CI, -0.97% to -0.65%; P < 0.001). Declines were observed across most age groups, with the steepest reductions among adults aged 45-54 years (AAPC, -1.68%; 95% CI, -2.01% to -1.35%) and 55-64 years (AAPC, -1.25%; 95% CI, -1.51% to -0.99%). Marked racial and ethnic disparities were identified. Non-Hispanic (NH) Black individuals experienced the most rapid decline (AAPC, -4.07%; 95% CI, -4.42% to -3.72%). Conversely, trends among NH White individuals remained stable overall (AAPC, -0.05%; P = 0.59), characterized by an initial increase from 1999 to 2005 (APC, 1.14%; P = 0.002) followed by a modest decline from 2005 to 2023 (APC, -0.44%; P < 0.001). Regionally, the West demonstrated the largest decline (AAPC, -1.13%; 95% CI, -1.26% to -0.99%), followed by the Northeast (AAPC, -1.05%). West Virginia was the only state to exhibit a significant increase in mortality (AAPC, 1.01%; 95% CI, 0.38% to 1.64%; P = 0.003). Mortality declined significantly in metropolitan areas (AAPC, -1.09%; P < 0.001), while trends in nonmetropolitan areas remained stagnant (AAPC, 0.48%; P = 0.12). Conclusions: Despite a national decline in esophageal cancer mortality, substantial disparities persist across racial, geographic, and urbanization groups. The dramatic improvement among NH Black populations contrasts with the relative stability in NH White populations and the lack of progress in nonmetropolitan areas. The significant rise in mortality in West Virginia warrants targeted investigation. These findings underscore the critical need for population-tailored strategies to ensure equitable progress in cancer prevention and care.

e16023 Background: Stroke is an underrecognized cause of death among patients with gastric cancer. While overall cancer mortality has improved, less is known about long-term trends and disparities in stroke-related deaths. We examined national patterns in stroke mortality among gastric cancer patients from 1999 to 2023. Methods: U.S. national mortality data were used to calculate age-adjusted mortality rates (AAMR) per 100,000. Joinpoint regression identified temporal changes and estimated annual percent change (APC) and average annual percent change (AAPC). Analyses were stratified by age, sex, race and ethnicity, census region, and urbanization. Results: Between 1999 and 2023, an overall decline in stroke-related mortality was noted with AAMR falling from 167.29 to 111.35 per 100,000 people (AAPC −1.70%, 95% CI −1.9 to −1.5). The decline was greatest between 2002 and 2009 (−5.28% per year) after which it began to plateau until it rose significantly between 2018 and 2021 (APC 6.56%) followed by a decline after 2021 (−3.63%). Older adults had the highest level of stroke related mortality, and therefore the greatest reduction over time (from 756.36 to 479.63) with a total reduction of −36.6% yet they saw a significant increase in mortality between 2018 and 2021. Middle aged patients had little overall improvement and demonstrated the steepest recent increase (APC 8.46%). Younger patients concluded the study period at rates similar to those seen in 1999. Men demonstrated a greater incidence of stroke related mortality compared to women (118.67 vs 104.15 in 2023) with similar trends over time. Racial disparities were present with Black patients showing the highest stroke related mortality in all years (from 242.47 to 156.26) and the largest recent increase (APC 7.37%). Regionally, the South and rural areas carried the highest mortality burden; however, all geographic areas demonstrated an identical increase between 2018 and 2021. Conclusions: Although stroke-related mortality among gastric cancer patients has declined over two decades, recent nationwide increases highlight ongoing vulnerability and persistent disparities. Targeted integration of cardiovascular risk assessment and stroke prevention into gastric cancer care may help sustain progress and reduce inequities. Group (Category A / Category B) AAMR 1999 (A / B) AAMR 2023 (A / B) Recent Surge Trend 2018–2021 (APC) Overall 167.3 111.4 +6.6%* Sex (Male / Female) 181.5 / 156.2 118.7 / 104.2 +6.8%* / +6.2%* Race (NH White / NH Black) 160.4 / 242.5 108.2 / 158.4 +6.3%* / +7.4%* Race (Hispanic / Asian) 140.3 / 153.6 97.7 / 80.0 +6.9%* / +5.2%* Age (Young / Middle) 6.7 / 47.7 6.7 / 42.3 +7.8%* / +8.5%* Age (Old 65+) 756.4 479.6 +6.2%* Region (Northeast / Midwest) 141.5 / 172.0 82.7 / 115.3 +4.4%* / +6.7%* Region (South / West) 177.5 / 171.4 125.7 / 107.2 +6.9%* / +6.2%* An asterisk (*) indicates that the APC is statistically significant (p < 0.05).

e16021 Background: Esophageal cancer (EC) remains highly lethal in the United States, with approximately 22,370 new cases in 2024. Respiratory failure (RF) frequently complicates advanced disease, and deaths involving both conditions have risen substantially since 1999, necessitating population-based mortality analysis. This study aimed to characterize national mortality trends involving EC and RF, with a focus on demographic, geographic, and urban–rural disparities. Methods: We conducted a retrospective analysis of U.S. deaths associated with EC (C15) and RF (J96) among adults aged ≥45 years using data from the Centers for Disease Control and Prevention WONDER database. Age-adjusted mortality rates (AAMRs) per 1 million were computed and stratified by year of death, sex, race, census region, and urbanization. Joinpoint regression estimated Average Annual Percent Changes (AAPC) with 95% confidence intervals (CI). Results: Between 1999 and 2024, 32,348 deaths were attributed to EC and RF. National AAMRs increased during this period from 8.2 to 13.7 (AAPC: 2.18*; 95% CI: 1.70 to 2.67). Males bore a higher mortality burden than females (AAPC: 2.23*; 95% CI: 1.7 to 2.7). Mortality was elevated in both examined age groups (45-64 and 64-85+), with the most significant impact observed among individuals aged 65-85+ years (AAPC: 2.52*; 95% CI: 2.02 to 3.02). Race-stratified analysis revealed non-Hispanic (NH) White individuals demonstrated the most pronounced increase across the study period (AAPC: 2.72*; 95% CI: 2.19 to 3.25). Geographically, the Midwestern census region showed the steepest rise in mortality, with rural counties nationwide exhibiting a similar increase(In Table). Conclusions: Mortality due to EC and RF has increased insidiously over the past two decades, while the literature on the combined effects of diseases remains limited. The burden is disproportionately higher among males, adults aged ≥65 years, and NH White individuals, particularly in Midwestern and rural regions. These disparities highlight a growing public health burden and emphasize the need for targeted prevention, early detection, optimized respiratory and oncologic care, and region-specific policies to mitigate inequities. Variable AAMR 1999 AAMR 2024 AAPC (95% CI) Overall 8.2 13.7 2.18*(1.70-2.67) Gender:FemaleMale 3.714 5.123.8 1.73*(0.89-2.56)2.23*(1.71-2.75) Census region:NortheastMidwestSouthWest 8.277.510.8 15.513.412.214.9 2.43 *(2.05-2.82)3.22 *(2.38-4.07)1.91*(1.06-2.77)1.30 (-0.16-2.80) Age:45-64years65-85+years 415.5 5.727.7 1.37(-0.01-2.78)2.52*(2.02-3.02) Race:HispanicNH WhiteNH Black 5.27.712.8 9.514.411.2 2.54*(1.76-3.33)2.72*(2.19-3.25)-0.41(-1.33-0.52) Urbanization: (1999-2020)MetroNon-Metro 1999 8.56.9 2020 11.313.8 1.34*(0.83-1.85)3.47*(2.25-4.71) *Indicates p<0.05.

e16018 Background: Intrahepatic cholangiocarcinoma (iCCA) exhibits marked heterogeneity in outcomes that is incompletely explained by stage or treatment timing. Although treatment delay is frequently cited as a modifiable risk factor, its prognostic significance in real-world practice remains unclear. We applied machine learning (ML) to model iCCA as a dynamic disease process and to evaluate whether longitudinal disease trajectories better explain outcomes than treatment timing alone. Methods: We conducted a population-based retrospective analysis of adults diagnosed with iCCA using the Surveillance, Epidemiology, and End Results (SEER) database (2000–2022). Time from diagnosis to first cancer-directed therapy was categorized as ≤30 days, 31–60 days, or > 60 days. Associations between treatment delay, disease characteristics, and overall survival (OS) were assessed using multivariable logistic and Cox regression models. To capture real-world disease evolution, each patient’s clinical course was encoded as an ordered longitudinal sequence of diagnosis, treatment states (surgery, chemotherapy, radiation), and outcome. Unsupervised ML was used to identify latent disease-course trajectories. A supervised ML model using variables available at diagnosis was developed to predict membership in high-risk trajectories. Results: The cohort included 18,312 patients with iCCA. Treatment initiation beyond 30 days occurred in more than half of patients and was more common in localized than advanced disease. In adjusted survival analyses, shorter time to treatment was paradoxically associated with worse OS, consistent with confounding by disease severity rather than a protective effect of delay. Unsupervised ML identified four distinct and reproducible disease trajectories with markedly different outcomes. Median OS ranged from approximately 2 months in early-failure trajectories to approximately 15 months in favorable multimodality trajectories. Trajectory membership was not fully explained by stage or treatment timing. A supervised ML model predicted high-risk trajectory membership with good discrimination (AUC 0.82). Key predictors included tumor grade, age, tumor burden, and incomplete staging, whereas treatment timing had minimal influence. Conclusions: In iCCA, treatment delay reflects underlying disease biology and care prioritization rather than independently determining survival. ML-based trajectory modeling reveals clinically meaningful disease courses that better explain outcome heterogeneity than treatment timing or stage alone and enables early identification of patients at highest risk for unfavorable real-world outcomes.

e14524 Background: Immune checkpoint inhibition has demonstrated meaningful clinical benefit in microsatellite instability–high (MSI-H) colorectal cancer (CRC); however, outcomes remain heterogeneous. The interaction between tumor immune microenvironment features, tumor mutational burden (TMB), and survival outcomes has not been fully characterized. We conducted an integrative analysis of publicly available genomic data to evaluate the prognostic impact of immune infiltration stratified by MSI status and TMB in CRC. Methods: Transcriptomic, somatic mutation, and clinical data for primary colorectal adenocarcinoma were obtained from TCGA-COAD and TCGA-READ. About 600 patients with overall survival data were analyzed. MSI status was taken from TCGA molecular subtype annotations. TMB was defined as the number of nonsynonymous somatic mutations per tumor and dichotomized at the median.Immune infiltration (CD8⁺ and CD4⁺ T cells, macrophages, neutrophils, dendritic cells) was estimated using TIMER. Patients were classified as high or low infiltration by the median. Overall survival was assessed using Kaplan–Meier analysis and Cox models adjusted for age, sex, and tumor stage., and tumor stage. Results: The cohort included approximately 15% MSI-H tumors, which demonstrated significantly higher TMB compared with microsatellite-stable (MSS) tumors. MSI-H tumors exhibited an inflamed immune phenotype, with approximately twofold higher CD8⁺ T-cell infiltration relative to MSS tumors. Across the overall cohort, high CD8⁺ T-cell infiltration was associated with improved OS compared with low infiltration (median OS not reached vs approximately 60–70 months). In contrast, increased macrophage infiltration was associated with inferior survival outcomes. When stratified by genomic features, the favorable prognostic association of CD8⁺ T-cell infiltration was most pronounced in MSI-H and TMB-high tumors, corresponding to an estimated 30–40% relative reduction in mortality risk compared with MSI-H/TMB-high tumors with low immune infiltration. Immune infiltration demonstrated weaker and less consistent associations with OS in MSS/TMB-low tumors. In multivariable analyses, CD8⁺ T-cell infiltration remained independently associated with improved OS after adjustment for clinical covariates, whereas macrophage infiltration remained independently associated with worse outcomes. Findings were consistent across colon and rectal cancer subgroups. Conclusions: In this integrative analysis of TCGA colorectal cancer datasets, features of the tumor immune microenvironment, together with MSI status and TMB, were associated with survival. These results support immune-genomic stratification and suggest that combining immune and molecular biomarkers may improve prognostic assessment and immunotherapy trial design in colorectal cancer.

e14111 Background: Primary CNSL (PCNSL) is a rare, aggressive B-cell non-Hodgkin lymphoma limited to the CNS, while secondary CNSL (SCNSL) represents CNS involvement from systemic lymphoma. Previous observations focused on CNSL have limited data clinically comparing PSNSL and SCNSL. We aimed to evaluate overall survival and associated factors in patients with PCNSL vs SCNSL using a large population database. Methods: We conducted a retrospective cohort study using the SEER-22 database to identify patients diagnosed with CNSL between 2020-2022. Group comparisons used t-tests or ANOVA for continuous variables, chi-square tests for categorical variables, and Kaplan–Meier survival analysis, with all analyses performed in RStudio 4.1.1 and significance deemed as p<0.05. Results: 14,964 patients with CNS lymphoma were identified, with 84.6% PCNSL and 15.4% SCNSL cases. The overall median age was 65 years (IQR 20), with 52% male, 66% White patients, residing in urban areas (90%) and median household income of $50,000–$75,000 (52%). Compared with PCNSL, patients with SCNSL were significantly older (72 vs 64 years, p<0.0001). SCNSL more frequently involved the cerebrum (39% vs 34%) and cerebellum (5.5% vs 4.5%), but less commonly affected the nerves (12.0% vs 12.5%) and spinal cord (4.2% vs 5.1%) (p<0.05). Disease was predominantly unilateral (95.8%) in both groups. Chemotherapy (55% vs 56%) and radiotherapy (19% vs 18%) utilization did not differ significantly, with external beam radiation comprising 94.3% of radiated cases. PCNSL patients were more likely to undergo surgical intervention than SCNSL patients (31.8% vs 28.7%; p=0.0027). Diffuse large B-cell lymphoma was the most common histologic subtype in both PCNSL (70.1%) and SCNSL (74.3%). Median overall survival was shorter in SCNSL (1.64 years) than PCNSL (1.99 years). Survival improved significantly across diagnostic eras (2000–2005 to 2016–2020; log-rank p<0.001), while lower income (<$50,000) and rural residence were associated with inferior outcomes (p=0.028 and p=0.033). Conclusions: Survival in CNS lymphoma remains poor, with SCNSL associated with worse outcomes compared with PCNSL. Greater understanding of treatment variation and disease differences is needed to optimize therapy and improve patient outcomes. Characteristic PCNSL SCNSL Total p-Value N 12667 2297 14964 Population Distribution 0.033 Urban 11426 2038 13464 Rural 1241 259 1500 Surgery 0.0027 Yes 3630 730 4360 No 9037 1567 10604 Months from Diagnosis to Rx(Mean, SD) 0.31 (0.86) 0.27 (0.65) 0.30 (0.83) 0.0077 Death Status <0.0001 Dead 8603 1772 10375 Alive 4064 525 4589 Overall Survival (in years, Mean, SD) 1.99 (2.85) 1.64 (2.31) 1.93 (2.77) <0.0001