Great Circle Research Articles

Modeling Civil Aviation Emissions with Actual Flight Trajectories and Enhanced Aircraft Performance Model

Aviation emissions are continuously increasing along with the rapid development of air transportation, and results in the deterioration in regional air quality and the global climate. Accurate emission estimation is of great importance for relevant policies promotion and the sustainable development of the environment. Previous studies focused on the total emissions of a flight and lacked high precision in both spatial and temporal resolutions, especially aviation activities near ground. In this research, we propose an open-sourced emission calculation framework based on actual flight trajectories (TrajEmission), which calculates both the ground and airborne emissions simultaneously according to the configuration parameters, trajectory characteristics, and ambient conditions. We compare the emission results with five emission inventory methods. The results indicate that pollutant (nitrogen oxides, carbon monoxide, and unburned hydrocarbons) emissions in the landing and takeoff (LTO) cycle might usually be underestimated due to a lack of trajectory-based methods. In addition, in the overall results, the method based on the great circle route leads to an overestimation of 56.8% of pollutant emissions compared to the method based on actual routes. We also investigate the extent to which other factors could influence the emission results. To summarize, the TrajEmission framework can build inventories for the whole process of flight movements with high spatial–temporal resolutions and provide solid data support for environmental science and other related fields.

Geodesic vector fields, induced contact structures and tightness in dimension three

In this paper, we provide new and simpler proofs of two theorems of Gluck and Harrison on contact structures induced by great circle or line fibrations. Furthermore, we prove that a geodesic vector field whose Jacobi tensor is parallel along flow lines (e.g. if the underlying manifold is locally symmetric) induces a contact structure if the ‘mixed’ sectional curvatures are nonnegative, and if a certain nondegeneracy condition holds. Additionally, we prove that in dimension three, contact structures admitting a Reeb flow which is either periodic, isometric, or free and proper, must be universally tight. In particular, we generalise an earlier result of Geiges and the author, by showing that every contact form on R3\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${\\mathbb {R}}^3$$\\end{document} whose Reeb vector field spans a line fibration is necessarily tight. Furthermore, we provide a characterisation of isometric Reeb vector fields. As an application, we recover a result of Kegel and Lange on Seifert fibrations spanned by Reeb vector fields, and we classify closed contact 3-manifolds with isometric Reeb flows (also known as R-contact manifolds) up to diffeomorphism.

Examining the influence of 2.5-D ultra-low velocity zone morphology on ScP waveforms and estimated elastic parameters

Summary Ultra-low velocity zones (ULVZs) have been identified as regions of extremely low velocity anomalies in the Earth's lowermost mantle using seismic observations from reflected, refracted, and diffracted arrivals along the mantle side of the core-mantle boundary (CMB). Estimation of ULVZ geometrical (i.e., shape and size) and elastic (i.e., velocity and density) parameters with uncertainties is crucial in understanding the role of ULVZs in the ongoing dynamic processes within the Earth's mantle; however, these parameters are still poorly known due to uncertainties and tradeoffs of the seismically resolved ULVZ geometries and elastic parameters. Computation of synthetic waveforms for 2-D and 3-D ULVZs shapes is currently computationally feasible, but past studies utilize higher dimensional waveform modeling of mostly only low-frequency diffracted waves. Most studies focusing on high-frequency core-reflected waveforms (e.g., ScP) still use 1-D modeling approaches to determine ULVZ properties. This approach might lead to wrong results if the imaged structures have inherently 3-D geometries. This study investigates high-frequency synthetic ScP waveforms for various 2.5-D ULVZ geometries showing that additional seismic arrivals are generated even when the ScP geometrical ray path does not directly strike the location of the ULVZ. The largest amplitude additional phases in the 2.5-D models are post-cursor arrivals that are generated at the edges of the finite-length ULVZs. These newly identified ScP post-cursors can arrive within the ScsP post-cursor time window traditionally analyzed in 1-D ULVZ studies. These post-cursors might then be misidentified or constructively/destructively interfere with the ScsP postcursor, leading to incorrect estimation of ULVZ parameters. In this study we investigate the bias introduced by the 2.5-D morphologies on the 1D estimated ULVZ elastic properties in a Bayesian waveform inversion scheme. We further expand the Bayesian method by including the data noise covariance matrix in the inversion and compare it to an autoregressive noise model that was utilized in previous studies. From the application to the observed ScP data, we find that the new approach converges faster, particularly for the inversion of data from multiple events, and the new algorithm retrieves ULVZ parameters with more realistic uncertainties. The inversion of 2.5-D synthetic ScP waveforms suggests that the retrieved ULVZ parameters can be misleading with unrealistically high confidence if we do not consider the data noise covariance matrix in the inversion. Our new approach can also retrieve the shape of a multi-dimensional Gaussian ULVZ if its length is 12o or longer in the great circle arc direction. However, 2.5-D synthetic waveforms show additional waveform complexity which can constructively interfere with the ScP wavefield. Hence, in many cases the estimation of ULVZ properties using 1-D forward modeling can provide incorrect ULVZ parameters. Hence previous ULVZ modeling efforts using 1-D parameter estimation methods may be incorrect.

Deformation, shape transformations, and stability of elastic rod loops within spherical confinement

Mechanical insight into the packing of slender objects within confinement is essential for understanding how polymers, filaments, or wires organize and rearrange in limited space. Here we combine theoretical modeling, numerical optimization, and experimental studies to reveal spherical packing behavior of thin elastic rod loops of homogeneous or inhomogeneous stiffness. Across varying loop lengths, a rich array of configurations including circle, saddle, figure-eight, and more intricate patterns are identified. A theoretical framework rooted in the local equilibrium of force and moment is proposed for the rod loop deformation, facilitating the determination of internal and contact forces experienced by the rods during deformation. For the confined homogeneous rod loops, their stable and metastable configurations are well described using proposed Euler rotation curves, which offer a concise and effective approach for configuration prediction. Moreover, formulated analysis on the stability and critical force for homogeneous rod loops on great circles of the spherical confinement are performed. For inhomogeneous rod loops with two segments of differing stiffness, the stiffer segment exhibits less deviation from the great circle, while the softer segment undergoes more pronounced deformation. These findings not only enhance our understanding of buckling and post-buckling phenomena but also offer insights into filament patterning within confining environments.

Geographic distance to Commission on Cancer-accredited and nonaccredited hospitals in the United States.

The Commission on Cancer (CoC) establishes standards to support multidisciplinary, comprehensive cancer care. CoC-accredited cancer programs diagnose and/or treat 73% of patients in the United States. However, rural patients may experience diminished access to CoC-accredited cancer programs. Our study evaluated distance to hospitals by CoC accreditation status, rurality, and Census Division. All US hospitals were identified from public-use Homeland Infrastructure Foundation-Level Data, then merged with CoC-accreditation data. Rural-Urban Continuum Codes (RUCC) were used to categorize counties as metro (RUCC 1-3), large rural (RUCC 4-6), or small rural (RUCC 7-9). Distance from each county centroid to the nearest CoC and non-CoC hospital was calculated using the Great Circle Distance method in ArcGIS. Of 1,382 CoC-accredited hospitals, 89% were in metro counties. Small rural counties contained a total of 30 CoC and 794 non-CoC hospitals. CoC hospitals were located 4.0, 10.1, and 11.5 times farther away than non-CoC hospitals for residents of metro, large rural, and small rural counties, respectively, while the average distance to non-CoC hospitals was similar across groups (9.4-13.6 miles). Distance to CoC-accredited facilities was greatest west of the Mississippi River, in particular the Mountain Division (99.2 miles). Despite similar proximity to non-CoC hospitals across groups, CoC hospitals are located farther from large and small rural counties than metro counties, suggesting rural patients have diminished access to multidisciplinary, comprehensive cancer care afforded by CoC-accredited hospitals. Addressing distance-based access barriers to high-quality, comprehensive cancer treatment in rural US communities will require a multisectoral approach.

Satellite group infall into the Milky Way: Exploring the Crater-Leo case with new HST proper motions

Context. Within Λ cold dark matter (ΛCDM) simulations, Milky Way-like galaxies accrete some of their satellite galaxies in groups of 3–5 members rather than individually, and this has been suggested as a possible mechanism driving the formation of satellite planes. Objects accreted in groups are expected to share similar specific total energy and angular momentum, and to also have identical orbital planes and directions. Aims. Looking at observatio ns of Milky Way satellites, the dwarf galaxies Leo II, IV, V, and Crater II, and the star cluster Crater 1 were proposed to be a vestige of group infall. The suggested ‘Crater-Leo group’ shows a coherent distance gradient and all these objects align along a great circle on the sky. We used proper motion data to investigate whether the phase-space distribution of the members of the proposed group are indeed consistent with group infall. Methods. To further investigate this possibility, we used Gaia Data Release 3 (DR3) and new Hubble Space Telescope (HST) proper motions – namely, (μα*, μδ) = (−0.1921 ± 0.0514, −0.0686 ± 0.0523) mas yr−1 for Leo IV and (μα*, μδ) = (0.1186 ± 0.1943, −0.1183 ± 0.1704) mas yr−1 for Leo V – to derive accurate orbital properties for the proposed group objects. In addition, we explored other possible members of this putative association. Results. Leo II, Leo IV, and Crater 1 show orbital properties consistent with those we predict from assuming group infall. However, our results suggest that Crater II was not accreted with the rest of the objects. If confirmed with increasingly accurate proper motions in the future, the Crater-Leo objects would appear to constitute the first identified case of a cosmologically expected, typical group infall event, as opposed to the highly hierarchical Magellanic Cloud system.

Travel and the Self in Maggie Shipstead's The Great Circle

Travel and the Self in Maggie Shipstead's The Great Circle

Simulated Warming Hole in Paleo-Pacific Oceans

Abstract Both observations and simulations show that under global warming, there exists a warming deficit in the North Atlantic, known as the North Atlantic warming hole (NAWH). Here, we show that a similar warming hole occurs in the subpolar Pacific Ocean of paleoclimate simulations. As the solar constant is increased, the local surface becomes substantially cooler rather than warmer in the subpolar paleo-Pacific Ocean under the land–sea configurations of 70, 90, and 150 million years ago (Ma). The warming hole has a magnitude of ≈3°C and is located in the Northern Hemisphere in 70 and 90 Ma. The warming hole in 150 Ma has a magnitude of ≈1°C and is located in the Southern Hemisphere. Both atmospheric and oceanic processes contribute to trigger the warming hole. For 70- and 90-Ma experiments, atmospheric teleconnection along a great circle from tropics to extratropics intensifies surface winds over subpolar ocean and thereby increases relatively cool seawater transport from high to low latitudes. Meanwhile, global meridional overturning circulation (GMOC) becomes weaker, causing a divergence of the meridional ocean heat transport in the warming hole region. An increasing regional cloud shortwave cooling effect acts to further enhance the warming hole. For 150-Ma experiments, the warming hole is related to the meridional shift of midlatitude jet stream and the weakening of GMOC in the Southern Hemisphere. The strength and phase of the atmospheric teleconnection and the response of GMOC strongly depend on land–sea configuration, resulting in the paleo-Pacific warming hole to occur in special periods only.

Reducing carbon footprint of ships in voyage planning: A case study of Atlantic passage

Determining the most efficient ship routes is crucial for ensuring both safety and fuel savings during voyage planning. Great circle Navigation (GC) and weather routing (WR) are the two most common methods used by navigators for ocean crossings. GC Navigation is renowned for its potential to save time and fuel by following shorter routes over long distances; however, it may expose vessels to adverse weather conditions and sea states due to navigating at higher latitudes. On the other hand, weather routing integrates pilot charts and meteorological data to identify safer routes, albeit potentially longer, minimizing risks associated with rough weather. This study focuses on route planning for a handy-sized tanker contracting a westbound Atlantic ocean voyage within a specific timeframe. The main objective of the study is to evaluate the efficacy of these two methods. The GC route components were computed using spherical trigonometry equations, while weather routing planning relied on pilot charts and meteorological data. Environmental conditions were simulated and tested in the Transas Full Mission Simulator (NTPRO 4000). The results reveal that the WR method provides 21.3% higher energy efficiency than GC. The insights derived from this research contribute significantly to enhancing the operational efficiency and safety standards of commercial vessels.

Asian-Australian monsoon as a mediator on North American surface air temperature anomalies

The Asian-Australian monsoon (AAM) significantly shapes global weather and climate patterns, yet existing research has primarily focused on regional monsoon subsystems rather than adopting a comprehensive global perspective on the AAM. This study addresses this gap by elucidating the interannual variability of the AAM during boreal summer and underscoring the pivotal mediating role of AAM precipitation anomalies as a driving force behind surface air temperature anomalies (SATA) over central and southern North America (CSNA). To investigate AAM characteristics, we employ an empirical orthogonal function analysis to identify the primary mode of the AAM. The corresponding principal component serves as a representative measure for the AAM. Our findings reveal a distinct ‘wet (dry) Maritime Continent-dry (wet) Western North Pacific (WNP)’ dipole pattern in strong (weak) AAM years. Vertical motion anomalies emerge as the dominant contributors to these precipitation anomalies. Both observed data and model results indicate that the sea surface temperature anomalies (SSTA) in the central and eastern Pacific (CEP) play a crucial role in explaining the vertical motion anomalies. This explanation is facilitated through two key systems: the east–west Walker circulation-like anomaly and the anomalous equatorially symmetric anticyclonic pair in the Pacific. AAM precipitation anomalies act as a mediator between SSTA in the CEP and SATA over the CSNA. These generate Rossby wave source over the WNP, triggering Rossby waves that propagate to CSNA along a great circle path. This process results in upper-level positive geopotential height anomalies, thereby influencing SATA positively over the CSNA, as illustrated by the linear baroclinic model. These findings not only deepen our understanding of the AAM but also offer novel insights into the mechanisms influencing SATA formation over North America.

Influencing factors for the human development index in West Java using geographically and temporally weighted regression kernel functions

Human Development Index (HDI) is a competitive index that serves as one of the crucial metrics for evaluating the effectiveness of enhancing the quality of human resources. HDI values from different areas can be compared. This study aims to spatially and temporally explore the HDI data from districts or cities in West Java and examine the factors that influence HDI in each of these districts or cities using the GTWR Great Circle Distance Fixed Kernels model. In this study, we used a combination of cross-sectional data from districts or cities in West Java and time series data with seven annual periods from 2015-2021. The GTWR Great Circle Distance Fixed Kernels model was expected to display coefficient values at each location and time simultaneously, providing more in-depth information and analysis results at each location and time. The analysis results using the GTWR Great Circle Distance Fixed Kernels model show that HDI in West Java carries a positive influence on the location and time. This finding should be of particular concern to the relevant government, particularly the factors presenting a natural effect on HDI based on location and time. The positive influence obtained by an area at a particular time will also have a positive impact on other regions, and if there is a negative influence, it will undoubtedly affect other regions as well. Analysis of the HDI model in West Java using the GTWR Great Circle Distance Fixed Exponential Kernel model also presents better results in comparison to the Global OLS model and the GTWR model without the Great Circle Fixed Exponential Kernel. The final parameter estimator results are displayed in the form of a geographic map to facilitate ease of understanding.

Atmospheric chemistry regimes in intercontinental air traffic corridors: Ozone versus NOx sensitivity

This study focusses on the environmental consequences of aircraft NOx emissions and their role and impact on ozone formation in the upper troposphere and lower stratosphere (UTLS). We use a global chemistry transport/box model approach to quantify the impacts of NOx on UTLS ozone over time scales of hours and over distance scales appropriate to air traffic corridors and aircraft flight paths. An important feature of our study has been to provide a marked contrast to the coarse spatial resolution of the global model studies typically employed to assess the impacts of aviation NOx on UTLS ozone. Real operational aviation routing data are used to quantify the NOx impacts on ozone at 235 locations on 21 flight paths. The NOx impact on ozone in the intercontinental air traffic corridors is strongest in the great circle routes from North America and Europe into Asia and weakest in the trans-polar routes. The NOx impacts identified with the CTM/box model combination are significantly smaller compared with those identified in the current global models typically used to assess aviation NOx impacts. Further research is required to confirm our assessment of those flight paths that appear to show greatest NOx – O3 impacts and those the least and extend our analyses into the tropics and southern hemisphere.

CALIPSO Observed Low Clouds Over the Subtropical Northeast Pacific: Summer Climatology and Interannual Variability

AbstractThis study examines the spatial distribution and temporal variations of low‐cloud top over the subtropical northeast Pacific (NEP), using observations from the Cloud‐Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO). A comparison between CALIPSO observations and in‐situ soundings reveals a distinct bimodal distribution of low‐cloud tops, characterized by peaks near the inversion base and transition layer, corresponding to shallow cumulus clouds below the stratocumulus deck and boundary‐layer decoupling phenomena. Climatologically, while traversing along a great circle from Los Angeles to Honolulu, the frequency of low cloud occurrence experiences a gradual reduction from 80% to 30%. Meanwhile, cloud top height increases from 0.6 to 1.6 km, and surface roughness varies from 50 to 300 m. This study marks the first presentation of long‐term characteristics of low clouds over a vast, remote area, expanding beyond discrete field campaign observations. Accurately characterizing the marine atmospheric boundary layer (MABL) including its depth and degree of decoupling, enables further investigation into the interannual variations of low clouds, using 14 years of CALIPSO observations. Significant interannual variability in areal fraction and vertical bimodality of low clouds emerges downstream of the anomalously cold water; increased cloud cover with weakened bimodality is associated with a shallow weakly decoupled MABL. This research emphasizes the need to consider the downstream effects in studying low cloud‐sea surface temperature feedback within climate models.

Statistical Analysis of Off‐Great Circle Radio Wave Propagation in the Polar Cap

AbstractHigh latitude ionospheric density structures such as polar cap patches and arcs are capable of deflecting high frequency (HF) radio waves to off‐great circle paths, and are likely detrimental to technologies dependent on HF radio propagation. In this study, nearly 2.5 years of 4.6–14.4 MHz data from a multi‐frequency HF radio link between Qaanaaq, Greenland and Alert, Canada are used to investigate high‐latitude off‐great circle propagation in the polar cap. After an example of HF radio propagation affected by polar cap patches is shown in detail, a statistical analysis of the occurrence and impacts of off‐great circle deflections in the polar cap is presented. Off‐great circle propagation is shown to be increasingly common with increasing frequency up to 11.1 MHz, such that averaged over 1 year, received 11.1 MHz signals experienced deflections >30° from the great circle direction 65.6% of the time. The occurrence of these deflections across the year is shown to be at a maximum in the winter, while occurrence across the day varies with season. Trends across both time of day and time of year for 11.1 and 14.4 MHz deflections are consistent with polar cap patch occurrence trends. Off‐great circle deflections are shown to be associated with increased time‐of‐flights, a larger range of positive and negative Doppler shifts, increased Doppler spreads, and lower signal‐to‐noise ratios. These results are discussed in the context of ionospheric phenomena in the polar cap, and implications for over‐the‐horizon radars operating at high latitudes.

Abstract 4839: Ethnicity dictates survival benefit in Hispanics diagnosed with diffuse large B-Cell lymphoma survival: A national cancer database analysis

Abstract Background: Diffuse Large B-Cell Lymphoma (DLBCL) is the most common Non-Hodgkin lymphoma in the United States (US) but there is limited evidence showing ethnic disparities affecting overall survival (OS) (Blood10.1182/blood-2022-159201, Blood10.1182/blood-2021-151816). This is the largest nationwide cancer registry analysis evaluating ethnic differences for HI vs Non-Hispanics (NH) with DLBCL in the US. Methods: Data were analyzed using the National Cancer Database from 2004-2019. Sociodemographic characteristics were compared between ethnic groups. Kaplan-Meier and Cox regression analyses were used to compare OS between HI and NH. Multivariate analysis and propensity score matching were performed with adjustment for age, stage, comorbidity score, and insurance status, type of facility, and great circle distance Results: 239,391 patients (HI n=18,290, NH n=221,101) were diagnosed with DLBCL. Male sex predominated for both and the majority of patients were Whites. HI were diagnosed at a median age of 62 years (y) vs 68 y for NH [p<0.001]. For HI and NH, most of the patients were diagnosed from 2016-2019. For both groups, the majority of patients had a Charlson-Deyo Score of 0, stage IV at diagnosis and unknown HIV status. The primary payer at diagnosis was government sponsored for HI and NH. In HI the median income based on the Median Income Quartile for 2000 corresponded to the highest level of >$46,000 and from 2008-2012 it was similarly distributed. For NH, for both time periods the majority of the patient were in the highest bracket. Most patients in the HI and NH were located in metropolitan area and were more likely to be treated at a comprehensive cancer center with a great circle distance (miles) of 7.3 for HI and 9.7 for NH. The median survival for HI was 11 y vs 6.8 y for NH. The survival probability at 2, 5 and 10 y for HI corresponded to 69%, 61% and 52%, while for NH it was 66%, 55% and 41%, respectively. The OS probability at 10 y was statistically significant favoring HI [p<0.0001]. Independently, on multivariate analysis, not insured status was associated with worse OS (HR 1.2, CI 1.13-1.28, [p<0.01]) and private insurance type was associated with better OS (HR 0.81, CI 0.77-0.84, [p<0.01]) Conclusion: This nationwide cancer registry study identified better OS in HI diagnosed with DLBCL in the US. Both cohorts had similar sociodemographic and clinical results; however, HI were diagnosed at younger age. This finding may not only help to explain a unique trait towards development of cancer at an earlier age, but also an enhanced response to therapy. Regarding median income there wasn’t a tendency noted for HI, which support the unique complex interactions in socioeconomic status. Further studies examining intrinsic biologic differences are needed to better understand improved OS for HI, which could also help the rational development of targeted therapies. Citation Format: Carolina Velez-Mejia, Esteban Toro Velez, Daniel Rosas, Qianqian Liu, Joel E. Michalek, Enrique Diaz Duque. Ethnicity dictates survival benefit in Hispanics diagnosed with diffuse large B-Cell lymphoma survival: A national cancer database analysis [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 4839.

Abstract 4823: Survival outcomes similar in T-cell/histiocyte-rich large B-cell lymphoma between Hispanics and non-Hispanics within the United States

Abstract Background: T-cell/histiocyte-rich large B-cell lymphoma (THRLBCL) is a rare variant of large B-cell lymphoma with features that overlap with Nodular lymphocyte-predominate Hodgkin lymphoma (NLPHL). (Blood PMID: 32871584, PLoS One PMID: 24244368,Haematologica PMID: 20207840). Unlike NLPHL, which has a good prognosis. THRLBCL’s prognosis is worse (Leuk Lymphoma PMID: 31287335). Given its rarity and difficulty to diagnose, limited studies explore prognostic factors for it. This study aims to explore clinical, demographic, and survival outcomes differ in Hispanic (HI) versus non-Hispanic (NH) patients with THRLBCL in the United States (US). Methods: Data were analyzed on THRLBCL patients in the US and reported to the National Cancer Database (NCDB) between 2004 and 2019. Demographic and treatment characteristics were compared between ethnic groups. Kaplan-Meier and Cox regression analyses compared OS between HI and NH. Multivariate analysis and propensity score matching was performed with adjustment for age, stage, co-morbidity score, insurance status, type of facility, and great circle distance. Results: Of 1252 THRLBCL patients, 7% were HI and 93% NH. 67% of HI were male, compared to 68% of NHHI pts were younger at diagnosis 55 vs 57 (p=0.471); the majority of HI and NH were <65, 64% and 66% respectively (p=0.574)Most of HI and NH were white (88% vs 74%). When examining stage, most of HI and NH were stage (IV) (50% vs 57%) (p=0.600)Regarding insurance type, Government-sponsored was the most prevalent in HI (52%), while private insurance was most prevalent for NH (51%) (p=0.001). The most non-Insured group was HI (11% vs 3%).Regarding Census Median Income (2008-2012), the most prevalent bracket (39.5%) for HI was $48,000 - $62,999, and for NH (31%) $>63,000. Charlson-Deyo Score (comorbidities score), HI had a 10% =/> 2 score, vs NH 7%. Regarding treatment facility type Academic/Research Programs were the most prevalent for HI (44%) and NH (38%).The median distance in miles between the patient’s residence and the hospital that reported the case (Great Circle Distance), HI lived at a median of 10 miles, vs NH at a median of 11 miles. On survival analysis, the survival probability at 2, 5, and 10 years of HI vs NH were 83% vs 83%, 77% vs 75%, and 69% vs 62%. The median survival time (MS) was not reached for HI or NH. There was no overall survival difference (OS) between HI/NH (p=0.8). Independently, on multivariate analysis, ethnicity was not associated with worse OS (HR 1.2, CI 0.67-2.17, p=0.54). Conclusion: The MS and OS between HI and NH with THRLBCL within the US were similar. However, due to the rarity of THRLBCL, the size of both populations was small, which reduces the confidence that there are no differences in the outcomes of these two populations. Because of this, more data is needed to evaluate further the clinical and socioeconomic factors that play a role in the survival outcomes of THRLBCL. Citation Format: Ian Mines, Daniela Urueta-Portillo, Qianqian Liu, Joel Michalek, Adolfo E. Diaz Duque. Survival outcomes similar in T-cell/histiocyte-rich large B-cell lymphoma between Hispanics and non-Hispanics within the United States [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 4823.

Abstract 4813: Demographic, treatment, and survival patterns in Hispanic vs. non-Hispanic patients with lymphoplasmacytic lymphoma/Waldenstrom macroglobulinemia: A national retrospective analysis from the National Cancer Database

Abstract Background: Lymphoplasmacytic lymphoma (LPL) is a rare type of non-Hodgkin B cell lymphoma. Waldenstrom macroglobulinemia (WM) is a form of LPL that presents with overproduction of IgM monoclonal protein. The understanding and treatment of LPL/WM has improved. However, few studies analyze LPL/WM in Hispanic (HI) patients specifically. This study aims to evaluate demographics, treatment, and survival patterns in HI vs. Non-Hispanic (NH) patients with LPL/WM. Methods: Data were analyzed on LPL/WM patients in the US reported to the NCDB from 2004-2019. Demographic and treatment characteristics were compared between ethnic groups. Kaplan-Meier and Cox regression analyses were used to compare overall survival (OS) between HI and NH. Multivariate analysis and propensity score matching were performed with adjustment for age, stage, co-morbidity score, insurance status, type of facility and great circle distance (GCD). Results: 17,915 patients were identified. 92% were NH, 3% were HI. Most patients were male in both NH and HI (p = 0.120). The median age at diagnosis for HI was 68 vs. 71 for NH (p < 0.001). Most HI and NH were white (87% HI, 91% NH p < 0.001). More HI were uninsured (8% HI, 1% NH p < 0.001) and were less likely to have government sponsored insurance (60% HI, 66% NH p < 0.001). Regarding income, most NH (42%) were in the $63,000+ bracket while most HI were in the $48,000-$62,999 bracket. Regarding education, reported in percent quartiles with no high school degree, most HI (41%) were in the > 21% bracket while most NH (35%) were in the 7-12.9% bracket (p < 0.001). Most HI (43%) were treated at academic/research programs; most NH were treated at comprehensive community cancer programs (38.4%, p < 0.001). Regarding comorbidities score, 9% of HI scored ≥ 2 vs 8% of NH (p 0.029). Regarding GCD, the median distance in miles between the patient’s residence and the hospital that reported the case, HI lived at a median of 6.7 miles vs 9 miles for NH (p < 0.001). Regarding treatment, 68% of HI were given treatment vs. 62% of NH (p < 0.001). There was no difference in mortality between HI vs. NH (30 day mortality p = 0.322; 90 day mortality p = 0.217). On survival analysis, the survival probability at 2, 5 and 10 years of HI vs NH were 81% vs 83%, 69% vs 68%, and 52% vs 46%, respectively. The median survival time (MS) was 10.6 years for HI vs 9 years for NH. There was no OS difference between HI vs. NH (p = 0.47). On multivariate analysis, there were no independent variables associated with better or worse OS. The propensity matched analysis showed no MS difference between HI vs NH (8.96 y vs. 8.74 y). Conclusion: We identified ethnic differences in age, race, insurance, education, income, location of treatment, GCD, staging, and treatment patterns. However, there was no statistically significant ethnic difference in MS or OS. Citation Format: Maria Elena Fierro, Heidi Latiolais, Qianquian Liu, Joel Michalek, Adolfo Enrique Diaz Duque. Demographic, treatment, and survival patterns in Hispanic vs. non-Hispanic patients with lymphoplasmacytic lymphoma/Waldenstrom macroglobulinemia: A national retrospective analysis from the National Cancer Database [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 4813.

Abstract 4857: Contemporary hospital-based study examining demographics, treatment patterns and survival outcomes of primary effusion lymphoma in the United States, with a specific emphasis on Hispanics

Abstract Background: Primary effusion lymphoma (PEL) is a rare and aggressive non-Hodgkin lymphoma associated with HIV and human herpesvirus 8 (HHV-8). (Blood PMID: 8695812). Without treatment, patients typically survive only two to three months (Oncol Res Treat PMID: 28253516) Limited research has been conducted on PEL, particularly in minorities in the United States. Limited research, especially in minority populations (Blood PMID: 30154110), has prompted a nationwide study comparing demographics, clinical characteristics, treatment patterns, and survival outcomes between Hispanic (HI) and Non-Hispanic (NH) PEL patients. Methods: Data on PEL patients from the National Cancer Database (NCDB) between 2004 and 2019 were analyzed in the US. Demographics and treatment characteristics were compared across ethnic groups. Kaplan-Meier and Cox regression analyses were used to compare overall survival (OS) between HI and NH populations. Multivariate analysis and propensity score matching were conducted, adjusting for age, stage, co-morbidity score, insurance status, type of facility, and great circle distance. Results: Of 459 PEL patients, 18% were HI, and 79% were NH. Both groups had mostly male patients (87% vs. 86%). HI patients were younger at diagnosis (mean 49 years vs. 57 years, p=0.163). Diagnoses were mostly from 2014-2019, and the majority were white (87% vs. 69%). Government-sponsored insurance was more prevalent in both groups (62% vs. 66%). HI had a higher percentage of uninsured individuals (8% vs. 5% NH) (p-value=0.01). The median income bracket was over $46,000 for both cohorts, HI 34% and NH 37%. Advanced comorbidities were similar between HI 50% and NH 43% based on Charlson-Deyo Score. The survival probabilities at 2, 5, and 10 years for HI vs NH were (40% vs 40%), (34% vs 289%), and (34% vs 24%), respectively. The median survival time (MS) was 0.8 years for HI and 0.9 years for NH. There was no overall survival (OS) difference (p-value=0.51). On multivariate analysis, there were no independent variables associated with better or worse OS. The propensity-matched analysis showed no MS difference between HI and NH (0.80 vs 0.71 years). Conclusion: This hospital-based analysis confirmed low survival rates and revealed no statistical differences in MS or OS among HI and NH individuals with PEL. Interestingly, the disease was more prevalent in high-income subjects in both cohorts, despite HI individuals having lower insurance rates. A better understanding of intrinsic disease characteristics and biological variables can offer valuable insights into how to unveil potential targets of better and hopefully meaningful therapies that could improve survival outcomes. Citation Format: Sergio A. Vallejo Avila, Joel Michalek, Qianquian Liu, Adolfo E. Diaz Duque. Contemporary hospital-based study examining demographics, treatment patterns and survival outcomes of primary effusion lymphoma in the United States, with a specific emphasis on Hispanics [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 4857.

Abstract 813: Primary cutaneous gamma-delta T-Cell lymphoma in the United States: A nationwide analysis of demographics and survival outcomes among the Hispanic population

Abstract BACKGROUND: Primary Cutaneous Gamma-Delta T-Cell Lymphoma (PCGDTCL) is a rare subtype of cutaneous T-cell lymphoma (CTCL) that, despite comprising <1% of cutaneous lymphomas, has gained recognition in recent years as an entity separate from other rare CTCLs. (LeukemiaPMID 35732829) A 5 year survival of 11% demonstrates a low response to current available therapies. (BloodPMID 30635287, Clin Hematol Int.PMID 35950208) Due to lack of consistency in behavior between CTCLs, there exists a need for studies of demographic, clinical, and survival disparities, including between Hispanics (HI) vs. non-Hispanics (NH). METHODS: Data were analyzed on PCGDTCL patients in the United States reported to the National Cancer Database (NCDB) between 2004-2019. Demographic and treatment characteristics were compared between ethnic groups. Kaplan-Meier and Cox regression analyses were used to compare OS between populations. Multivariate analysis and propensity score matching was performed with adjustment for age, stage, co-morbidity score, and insurance status, type of facility and great circle distance. RESULTS: Among 132 PCGDTCL patients studied (5% HI, 92% NH), the HI group was younger at diagnosis than NH (49.5y vs. 60y) (p=0.384); The majority of HI (50%) was diagnosed between 2010-2012 vs 2017-2019 for NH (45%) (p=0.673). Most of HI and NH were white (67% vs 79%). Private insurance was the most prevalent type in HI (67%) vs government sponsored for NH (49%). The most non-Insured group was NH (3%) vs HI (0%). The most prevalent bracket for Census Median Income (2008-2012) was $63,000+ for both HI (50%) and NH (31%). 17% HI vs 13%. NH had median income <$38,000. For Charlson-Deyo Score (comorbidities score), HI had 0% =/> 2 score, vs NH 6%. NCI-designated comprehensive cancer centers were the most prevalent type of facility providing care for HI (100%) and NH (56%) Survival probability (OS) at 2, 5 and 10y (HI vs NH) were (80% vs 48%), (80% vs 44%), and (80% vs 26%), respectively. Median survival time (MS) was not reached for HI vs 1.9 years for NH. Overall survival (OS) difference favored HI (p=0.13) On multivariate analysis, there was no independent variable associated with better or worse OS. Interestingly, the propensity matched analysis demonstrated significant MS difference between HI vs NH (median not reached vs. 1.35 years). CONCLUSION: There was no significant difference in OS between groups; however, the weighed MS favored the HI cohort, likely in part due to the difference in numbers between cohorts. The drastically low survival in all demographics is consistent with prior studies. These results demonstrate an unmet need for more comprehensive studies with the potential inclusion of correlatives looking at intrinsic biologic characteristics that may offer insight into druggable targets, aiming for improvement in survival outcomes for this rare lymphoma. Citation Format: Katherine Thiel, Rosa White, Qianqian Liu, Joel Michalek, Adolfo Enrique Diaz Duque. Primary cutaneous gamma-delta T-Cell lymphoma in the United States: A nationwide analysis of demographics and survival outcomes among the Hispanic population [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 813.

Abstract 6468: Nodular lymphocyte predominant hodgkin lymphoma: A national cancer database analysis with focus on hispanics

Abstract Background:Nodular lymphocyte-predominant Hodgkin lymphoma (NLPHL) is a rare and distinct subtype of Hodgkin Lymphoma.(PMID 26149294) 80% manifest at early stages, with a male and black race predilection.(PMID 26149195) Previous analysis have shown similar survival of Hispanics (HI) compared to Non-Hispanics (NH).(J Clin Oncol 10.1200/JCO.2023.41.16_suppl.e19512) This National Cancer Database (NCDB) analysis aims to clarify how sociodemographic factors affect presentation and survival in HI vs NH patients with NLPHL. Methods:Data were analyzed on NLPHL patients in the United States reported to the NCDB 2004-2019. Demographic and treatment characteristics were compared between ethnic groups. Kaplan-Meier and Cox regression analyses were used to compare overall survival (OS) between HI and NH populations. Multivariate analysis and propensity score matching was performed. Results:Of 5517 of NLPHL patients, 379 were HI, and 4904 NH. Male gender and white race predominated for both. HI were diagnosed at a younger median age of 44 years (y) vs 48 y for NH, p=0.001. Most patients were diagnosed between years 2016-2019. Stage I predominated for both, p<0.001. As to Charlson-Deyo score ≥2, both HI and NH had 4%. Private insurance as primary payer was the most prevalent type for HI (53%) and NH (65%). HI had a higher percentage of unknown/uninsured, 12% vs 6% for NH, p<0.001. In relation to census median income (2008-2012), the most prevalent bracket for HI (27%) was $48,000-$62,000, and for NH (35%) was >$63,000. Regarding median income of <$38,000, HI were 29% vs 16% for NH, p<0.001. For median distance in miles (mi) between the patient’s residence and the hospital that reported the case (great circle distance), HI lived at a median of 6.3mi, vs NH at median of 9.5mi. Majority of HI (56%) were treated at Academic/Research programs; while most of NH (39%) were treated at Comprehensive Community Cancer programs, p<0.001. On survival analysis, the survival probability at 2, 5 and 10 y for HI was 96%, 92%, 86%, vs for NH was 96%, 92%, 84%, respectively. The median survival time wasn’t reached for both HI and NH, and no statically significant difference was seen, p=0.57. On multivariate analysis, HI was not associated with worse OS (HR 0.76, CI 0.44-1.31, p=0,33). The propensity matched analysis confirmed not reached OS on both cohorts. Conclusion:NLPHL is a disease that affects young males, at early stages, for both HI and NH. Unlike previous studies, in this analysis white race predominates; which could be explained by the increase in reported cases over years. Despite HI having more uninsured population with lower median income quartiles, this wasn’t a barrier to access care at academic/research programs. Although no difference in OS was seen among ethnicities, there is a tendency that might favor HI. More studies are needed to determine if specific demographic factors truly influence survival in NLPHL. Citation Format: Esteban Toro Velez, Daniel Rosas, Carolina Velez-Mejia, Qianqian Liu, Joel Michalek, Adolfo Enrique Diaz Duque. Nodular lymphocyte predominant hodgkin lymphoma: A national cancer database analysis with focus on hispanics [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 6468.