Baidoun, Firas

Abstract Secondary central nervous system (CNS) large B-cell lymphoma (SCNSL) occurs in the de novo setting, as a CNS-isolated relapse, or synchronous (concomitant CNS and systemic) relapse. SCNSL is a devastating event without therapeutic consensus. Thus, we aimed to evaluate treatment outcomes in an international cohort. Progression-free survival (PFS), overall survival (OS), and cumulative incidence of relapse (CIR, estimated using competing-risk models) were reported. Prognostic factors were identified in a 6-month landmark multivariate analysis. Outcomes after thiotepa autologous stem cell transplant (ASCT) and chimeric antigen receptor (CAR) T-cell therapy (CAR-T) delivered at relapse were compared after propensity score matching (PSM). A total of 1139 patients were included in the analysis (de novo: 537; relapsed SCNSL: 602). Two-year PFS estimates were 40.4%, 43.9%, and 16.2% for de novo SCNSL, CNS-isolated relapse, and synchronous relapse, respectively. Patients with CNS-isolated relapse demonstrated low rates of systemic recurrence (24-month CIR, 6%). Thiotepa-ASCT correlated with longer survival in de novo SCNSL (PFS: hazard ratio [HR], 0.57; P = .005; and OS: HR, 0.62; P = .023) and CNS-isolated relapses (PFS: HR, 0.55; P = .002; and OS: HR, 0.39; P< .0001). ASCT (thiotepa or no thiotepa) also associated with improved survival in synchronous relapses (PFS: HR, 0.57; P = .023; and OS: HR, 0.48; P = .019). Higher survival with thiotepa-ASCT than CAR-T was observed after PSM (PFS: HR, 0.45; P = .005 and OS: HR, 0.41; P = .014). These data support thiotepa-ASCT in eligible patients, particularly de novo disease and CNS-isolated relapses. CNS-isolated relapse was infrequently associated with systemic recurrence, supporting treatment regimens adopted from primary CNS lymphoma.

Abstract The benefit of rituximab maintenance after first-line (1L) bendamustine-rituximab (BR) in patients with mantle cell lymphoma (MCL) remains uncertain, with inconsistent results from the phase 2 MAINTAIN trial and several retrospective studies. We conducted a large retrospective study at 27 US and Canadian academic centers to examine the benefit of rituximab maintenance after BR. A total of 911 patients received 1L BR between 2010 and 2020, and 703 had an objective response and no evidence of disease progression at the 3-month post-BR landmark. Among those, 394 (56%) received rituximab maintenance and 309 (44%) did not, with largely similar baseline patient and disease characteristics. In the landmark analysis, rituximab maintenance was associated with improved event-free survival (EFS; median, 49.9 vs 29.7 months; P< .001) as well as overall survival (OS; median, 109.5 vs 74.2 months; P< .001). The EFS and OS benefits were observed across most of the subgroups. EFS and OS differences were statistically significant in those who achieved a complete response to 1L BR (n = 590; median EFS, 62.7 vs 31.1 months [P< .001]; median OS, 136.1 vs 75.3 months [P< .001]), but the analysis among those who achieved a partial response to 1L BR was limited by the small sample size. These results provide additional evidence for the survival benefit of rituximab maintenance after BR in MCL and support its use in clinical trial design and routine practice.

Abstract Introduction Peripheral T-cell lymphoma not otherwise specified (PTCL-NOS) is the most common subtype of peripheral T-cell lymphoma. It is characterized by aggressive clinical behavior and poor prognosis and treatment often includes chemotherapy, but the benefit of hematopoietic stem cell transplantation (HSCT) remains an area of ongoing investigation. Using the National Cancer Database, we analyzed the impact of HSCT on survival in a large cohort of patients with PTCL-NOS. Materials and Methods We queried the National Cancer Database (NCDB) for patients aged 18 or older diagnosed with PTCL-NOS between 2004 and 2019. Patients who lost to follow-up were excluded. We analyzed the impact of HSCT on overall survival (OS) using Kaplan-Meier estimates and multivariate Cox regression to identify factors associated with OS. Results A total of 14,301 patients with PTCL-NOS were included in this analysis. Among them, 60.1% were male, 65.7% were Caucasian, 17.1% were black and 7.4% were Hispanic. Early-stage disease (stage I or II) was present in 24.1%, while 49.3% patients had advanced-stage disease (stage III or IV). The median age at diagnosis was 65 years (range 18-90, 23.6% were above age 75), and the median overall survival (mOS) was 15.3 months (95%CI 14.6-16), with a median follow-up of 82.8 months (95%CI 80.4-85.2). Regarding first-line treatment, 11.7% received radiation therapy, 68.9% received chemotherapy, and 6.6% underwent HSCT. The percentage of patients receiving HSCT increased from 3.3% in 2004 to 9.9% in 2019, tripling over the 16-year period. Transplant utilization varied by race/ethnicity: 7.3% of white patients underwent HSCT, compared to 6.4% of Hispanic and 4.3% of Black patients (P < 0.001). Socioeconomic disparities were also observed: patients with insurance were more likely to receive HSCT (6.8%) compared to those without insurance (2.1%); HSCT rates increased with income, from 3.9% in the lowest quartile to 8.1% in the highest; and patients from areas with higher education levels had nearly double the HSCT rate (8.4%) compared to those from the lowest-education areas (4.5%) with P<0.001 for all. In patients with advanced-stage disease, the mOS was 10.5 months (95%CI 9.8-11.1). Patients who received HSCT had significantly improved survival compared to those who did not (mOS 110.9 vs. 11.1 months; P < 0.001). Among those who underwent HSCT, there was no significant difference in survival between auto (N=207) and allo (N=47) mOS 118.9 vs. 95.7 months; P = 0.128. A similar trend of improved survival with HSCT and no significant difference between autologous and allogeneic HSCT was observed across all racial/ethnic groups: in Hispanic patients mOS in HSCT (N=31) vs. no HSCT (N=456) 106.2 vs. 8.8 months; P < 0.001. comparison between auto and allo was not performed due to the low number of allogeneic transplants (N=2). In Black patients mOS inHSCT (N=47) vs. no HSCT (N=1,215) 69.7 vs. 8.8 months; P < 0.001 and mOS in auto vs. allo NR in both groups; P = 0.764. InCaucasian patients mOS in HSCT (N=419) vs. no HSCT (N=4,111) 111.8 vs. 8.8 months; P < 0.001 and mOS in Auto vs. allo 118.9 vs. 99.4 months; P = 0.263. On multivariate analysis, older age, male gender, black race, presence of B-symptoms at diagnosis, HIV positive status, higher comorbidity score and receiving allogeneic (vs. autologous) HSCT were associated with worse survival. In contrast, having medical insurance, receiving radiation therapy, chemotherapy, and undergoing HSCT (vs. no HSCT) were associated with improved survival. Conclusion HSCT was associated with significantly improved overall survival in patients with PTCL-NOS, especially in those with advanced-stage disease. This survival benefit was consistently observed across racial and ethnic groups. These findings might be related to transplant eligibility. However, allogeneic HSCT was linked to worse outcomes compared to autologous HSCT, likely due to higher transplant-related mortality or selection bias of more aggressive diseases to undergo allogeneic transplant. Even though the trend reflects a growing adoption of HSCT as part of treatment strategies in advanced-stage PTCL-NOS over time, transplant utilization varied significantly by sociodemographic factors (insurance, education and income level), highlighting potential disparities in access to this potentially life-prolonging therapy. Further prospective studies are needed to refine transplant strategies and improve patient selection.

Abstract Introduction Biliary-tract cancers, including intra- and extra-hepatic cholangiocarcinoma and gallbladder carcinoma, are uncommon but highly lethal. They represent roughly 2–3 % of new cancer diagnoses yet contribute about 5 % of cancer-related deaths. Complete surgical resection remains the foundation of curative treatment, whereas the value of peri-operative chemotherapy continues to be debated. Materials and Methods The National Cancer Database (NCDB) was queried for patients diagnosed with non- metastatic biliary tract cancer at age 18 or older between 2004 and 2019. After excluding patients with unknown timing of surgery and chemotherapy, patients who died within 90 days of the most definitive primary site surgery, and patients lost to follow-up, we split the cohort into three groups according to the clinical stage (stage I-III). Then, we evaluated the overall survival (OS) between the different treatment modalities (surgery only, chemotherapy only, adjuvant chemotherapy following surgery, and neoadjuvant chemotherapy followed by surgery) in each group. We studied the OS using Kaplan-Meier estimates and multivariate Cox regression analyses to evaluate factors associated with OS. Results A total of 35,260 patients with non-metastatic biliary tract cancers were included in the analysis, of which 50.4% were females, 83% Caucasians, and 9.5% African Americans. The median age at diagnosis was 70 (range 18-90). 14,757 (41.9%) were stage I, 12,472 (35.4%) stage II, and 8,031 (22.8%) stage III. 7,286 (20.7%) had surgical resection only, 8,144 (23.1%) had chemotherapy only, 6,964 (19.7%) had surgical resection with perioperative chemotherapy, and 12,866 (36.5%) did not receive any treatment. We compared survival between different treatment modalities based on clinical stage. In stage I, patients treated with surgery alone exhibited superior median OS compared with those receiving adjuvant chemotherapy (65.7 vs 50.4 months, P < 0.001). Median OS after neoadjuvant chemotherapy was numerically higher than surgery alone (79.8 vs 65.7 months); however, this difference was not statistically significant (P = 0.63). Whereas in stage II, patients who were treated with adjuvant and neoadjuvant chemotherapy had better mOS compared to those treated with surgery only (33.9 and 40.3 vs 29.9 months with P<0.001 and P=0.005, respectively). The same trend was seen in stage III, patients who were treated with adjuvant and those treated with neoadjuvant chemotherapy had better mOS compared to surgery only (22.6 and 41.5 vs 19.5 months, respectively, with P<0.001 for all). In multivariate analysis, adjuvant and neoadjuvant chemotherapy did not affect the OS in all stages, except in stage III, where neoadjuvant chemotherapy was associated with better OS (HR 0.646, 95% CI 0.530-0.786; P<0.001). Conclusion Adjuvant and neoadjuvant chemotherapy do not seem to have a survival benefit in early-stage (stage I and II) biliary tract cancers, whereas neoadjuvant chemotherapy tends to improve OS in stage III.

Objectives: Anaplastic thyroid cancer (ATC) is a rare and aggressive type of thyroid malignancy with a very poor prognosis and outcome despite therapy. The rarity of this disease and the poor functional status of ATC patients limit the ability to conduct clinical trials, thus there is a lack of large, controlled trials to guide treatment and evaluate the benefit of combined modality therapy. Methods: The National Cancer Database (NCDB) was queried for patients diagnosed with ATC at age 18 or older between 2004 and 2018. After excluding patients with unknown number of treatment modalities, Charlson-Deyo score—a weighted summary of 17 chronic disease categories where higher scores denote greater baseline comorbidity burden—of 3 or more and patients lost for follow-up, we split the cohort into 3 groups according to the number of treatment modalities they received. Treatment modalities included surgery, radiation, and systemic therapy. Then, we evaluated the overall survival (OS) between the 3 groups. We studied the OS using Kaplan-Meier estimates and multivariate Cox regression analyses to evaluate factors associated with OS. In addition, propensity score matching (accounting for age, sex, race, Charlson-Deyo score, and clinical M stage) was used for more robust results. Results: A total of 3460 patients with ATC were included in the analysis, of which 1472 (42.5%) either received one type of therapy or did not receive any therapy (group 1), 1092 (31.6%) received bimodal therapy (group 2), and 896 (25.9%) received trimodal therapy (group 3). We found that group 3 had better OS compared with group 1 and group 2 (median OS 9.1 vs. 1.7 and 4.9 mo, respectively, with P <0.001 for all comparisons). Propensity score matching yielded 896 patients in each group. We found that group 3 had better OS compared with group 1 and group 2 (median OS 9.1 vs. 1.9 and 5.2 mo, respectively, with P <0.001 for all comparisons). Same trend was found in subgroup analysis when we split the cohort according to the metastatic status; in M0 group (median OS was 10.4 vs. 1.9 and 6.1 mo, respectively, with P <0.001 for all), in M1 group (median OS was 5.9 vs. 1.4 and 3.7 mo, respectively, with P <0.001 for all). Modality-specific analyses further demonstrated that surgery, radiation, and systemic therapy each independently prolonged OS in both M0 and M1 cohorts (all P <0.001). These individual benefits explain the additive advantage of trimodal therapy and underscore that offering at least one evidence-based modality is preferable when comprehensive treatment is infeasible. On multivariate analysis, group 1 and group 2 were associated with worse OS compared with trimodal treatment (HR: 2.721; 95% CI: 2.466-3.002 and HR: 1.434; 95% CI: 1.299-1.582, P <0.001 for all). Conclusions: Patients with ATC who were treated with intensive trimodal therapy had statistically significant improvement in OS compared with patients who received less intense therapy. This survival benefit was observed in both metastatic and nonmetastatic groups. Although we acknowledge the limitations of this retrospective analysis, our results showed the critical role of an intensive therapy approach in this aggressive malignancy.

Objectives: Hepatocellular carcinoma (HCC) is the most common type of liver malignancy and the third leading cause of cancer-related death in the world. Liver transplant is a cornerstone in treating nonmetastatic disease, but a significant portion of patients miss the opportunity of upfront liver transplant given the long waiting time for donor organs. Herein, we compare the survival outcomes between upfront liver transplant, liver transplant with bridge systemic therapy, and systemic therapy only. Methods: The National Cancer Database was queried for patients diagnosed with non-metastatic hepatocellular carcinoma (HCC) between 2004 and 2017. After including only patients with clinical N0 stage who received either systemic therapy alone, liver transplant alone or liver transplant with bridge systemic therapy, we split the cohort into 3 groups: systemic therapy only (including intra-arterial chemotherapy eg, TACE) group, upfront liver transplant group and liver transplant with bridge systemic therapy group. We evaluated overall survival (OS) among the three groups. We studied the OS using Kaplan-Meier estimates and multivariate Cox regression analyses to evaluate factors associated with overall survival (OS). Results: A total of 29,691 patients with nonmetastatic HCC were included for analysis, of which 25,122 (84.6%) were treated with systemic therapy only, 2513 (8.5%) were treated with bridge systemic therapy followed by liver transplant, and 2056 (6.9%) were treated with upfront liver transplant without systemic therapy bridge. We found that patients who were treated with bridge systemic therapy followed by liver transplant and patients who were treated with upfront liver transplant had a statistically significantly better OS compared to patients who were treated with systemic therapy only (mean OS was 101.9 mo and 98.2 vs. 39.4 mo, respectively, with P <0.001 for all). Whereas there was no significant difference in OS between patients who were treated with bridge systemic therapy followed by liver transplant and patients who were treated with upfront liver transplant (mean OS was 101.9 vs. 98.2 months, P =0.187). On multivariate analysis, factors associated with worse OS were older age (HR: 1.011; 95% CI: 1.010-1.013; P <0.001), Male sex (HR: 1.048; 95% CI: 1.014-1.084; P =0.006), White compared with African American race (HR: 1.055; 95% CI: 1.012-1.099; P =0.011), no insurance status (HR: 1.155; 95% CI: 1.079-1.237; P <0.001), clinical T4 stage compared with T0 stage (HR: 1.366; 95% CI: 1.257-1.483, P <0.001), and systemic therapy alone compared with upfront liver transplant and liver transplant with bridge systemic therapy (HR for upfront liver transplant and transplant with bridge systemic therapy vs. systemic therapy was 0.202; 95% CI: 0.184-0.223, and HR: 0.194, 95% CI: 0.178-0.212, respectively, with P <0.001 for all). Conclusions: Patients with nonmetastatic HCC who were treated with upfront liver transplant or liver transplant with bridge systemic therapy had statistically significant improvement in OS compared with patients who were treated with systemic therapy only. While our study confirms the survival benefit of liver transplant among patients with nonmetastatic HCC, these results raise the importance of proceeding with liver transplant after intra-arterial and/or systemic treatments in patients who are not initially eligible for or missed the opportunity of upfront liver transplant.

9029 Background: Addressing guideline concordant FP and TPP with cancer is challenging, especially for OT. SIM, a well-known education tool, has not been traditionally used to teach these topics. As part of the hematology/oncology fellowship curriculum, we designed a SIM applying LSP to bridge this educational gap. Methods: Applying LSP of contrasting cases, elaboration, feedback, generation and just-in-time telling, chief OTs and faculty designed a SIM with 3 clinical scenarios (CS) and 3 standardized pts (SP): FP for a female pt hospitalized for acute lymphoblastic leukemia tx, FP for a male pt in clinic for germ cell tumor tx, and breast cancer tx for a pregnant pt in 2 nd trimester. OT received written educational materials (WEM) and attended a lecture 1 week and 1 day pre SIM, respectively. OT were split into 2 groups; 1 started in the FP CS and 1 in the TPP CS, and then they switched. To reduce cognitive overload, each OT participated in 1 of 2 FP CS: half in the female FP CS and half in the male. Faculty and chiefs led debriefing sessions after all CS. The FP debrief ended with a special “learner as a teacher” part, where OT who attended the female CS taught those from the male CS about their topic and vice versa. The SIM concluded with "take-home" points. Pre (after having WEM) and post SIM anonymous surveys and verbal feedback assessed OT comfort, perceptions, and knowledge. Results: A 3 hour SIM with 14 OT and 5 faculty was completed successfully. SIM ended with all OT verbally sharing a learning point and positive feedback. All OT filled pre and post SIM surveys. Pre SIM, 17% reported having prior FP education, and 42% had prior TPP education. However, only 8% and 25% felt adequately prepared for FP and TPP discussions, respectively. Post SIM survey showed major improvement in comfort and knowledge about FP and TPP (see table 1). 75% of OT favored a combination of SIM and learning by teaching over other SIM formats. 83% supported having a TPP lecture before SIM. 100% reported satisfaction with FP and TPP SIM’s quality and wanted similar activities in the future. 92% were satisfied with the learner as a teacher tool. 100% felt education about FP and TPP with cancer should be part of fellowship training. Moral/cultural concerns were discussed as possible challenges in FP education. Conclusions: The application of LSP through SIM significantly increased OTs’ comfort discussing FP and TPP with cancer, and objectively enhanced their knowledge on these topics compared to after reading WEM. The SIM was largely perceived as a successful activity to educate about challenging topics and should become part of fellowship curriculum. Pre SIM % Post SIM % Comfortable addressing FP 17 92 Comfortable addressing TPP 8 100 Correct answers about female FP 63 83 Correct answers about male FP 67 94 Correct answers about TPP with cancer 68 98

Introduction: Myeloma therapeutics have tremendously improved in recent times, leading to unprecedented outcomes. Timely initiation of effective treatment is vital to improving survival and quality of life. Patient refusal to receive treatment is infrequent but certainly leads to increased morbidity/mortality. We studied factors associated with treatment refusal. Methods: The National Cancer Database (NCDB) was queried for adult patients diagnosed with MM between 2004-2021. Those who refused treatment for initial management despite physician's recommendation were identified. Patients with multiple primary malignancies or unknown treatment status were excluded. Patients' demographics and socioeconomic factors were collected. Kaplan-Meier and multivariate Cox regression were used to evaluate the likelihood of treatment refusal in the whole cohort and in each racial/ethnic group. Results: Out of 86,350 eligible patients with MM who were recommended to initiate therapy, 2,508 (2.9%) did not receive any treatment due to refusal. Of these, 52.6% were females, 64% were non-Hispanic White (NHW), 21.3% were non-Hispanic African American (NHAA), and 5.2% were Hispanic. On multivariate analysis, patients who were treated at comprehensive and integrated facilities were more likely to refuse treatment as compared to those at academic facilities (OR=1.36; 95% CI: 1.22-1.52, p&lt;0.001 and OR=1.22; 95% CI: 1.07-1.4, p=0.004, respectively). Patients on Medicare (OR=1.42; 95% CI: 1.16-1.73, p&lt;0.001), and presence of higher Charlson Comorbidity Index (CCI) also had a higher likelihood of refusing treatment. Lower refusal rates were seen for male gender (OR=0.83; 95% CI: 0.76-0.91, p&lt;0.001), NHW racial/ethnic group (as against NHAA; OR=0.34; 95% CI: 0.16-0.71, p=0.004), being insured (OR=0.69; 95% CI: 0.52-0.93, p=0.015), having private insurance (compared to Medicaid; OR=0.47; 95% CI: 0.38-0.59, p&lt;0.001) and having a higher income level (OR=0.82; 95% CI: 0.70-0.96, p=0.013). Among NHAA patients, 2.8% refused treatment and were more likely to have Medicare (OR=1.4; 95% CI: 1.03-1.9, p=0.032). Having private insurance (compared to Medicaid; OR=0.61; 95% CI: 0.43-0.88, p=0.008) had a lower likelihood of refusing treatment. Among NHW, 2.9% refused treatment and they were more likely to be treated at community, comprehensive and integrated facilities compared to academic facilities (OR=1.39; 95% CI: 1.12-1.73, p=0.003, OR=1.54; 95% CI: 1.33-1.77, p&lt;0.001 and OR=1.38; 95% CI: 1.16-1.64, p&lt;0.001, respectively), be from rural areas (OR=1.43; 95% CI: 1.05-1.96, p=0.025), and have a higher CCI. On the other hand, male gender (OR=0.79; 95% CI: 0.72-0.89, p&lt;0.001), private insurance (compared to Medicaid; OR=0.42; 95% CI: 0.30-0.59, p&lt;0.001) and higher income level (OR=0.80; 95% CI: 0.66-0.98, p=0.029) had a lower likelihood of refusing treatment. Among Hispanic patients, 2.3% refused treatment and were more likely to have Medicare (OR=1.96; 95% CI: 1.13-3.4, p=0.016), while those with private insurance (compared to Medicaid; OR=0.32; 95% CI: 0.14-0.73, p=0.007) had a lower likelihood of refusing treatment. Conclusions: This large real-world analysis highlights the intricate sociodemographic and economic factors that affect the decision of a MM to not proceed with the recommendation for treatment. (1) NHW are less likely to refuse treatment as compared to NHAA. (2) Insurance status is an important driver of refusal and transcends race/ethnicity. Furthermore, in this study, we highlight characteristics that are specific to different racial/ethnic groups like CCI which affect only certain racial/ethnic groups. This provides an opportunity to develop targeted interventions such that the benefit of therapeutic advancements can be realized by all.

Introduction: Mantle cell lymphoma (MCL) is an uncommon B-cell non-Hodgkin lymphoma (NHL) Prognosis is highly variable due to underlying biological and molecular heterogeneity. The first-line (1L) treatment paradigm for MCL continues to evolve with increasing use of bruton tyrosine kinase inhibitors (BTKi) and decreasing use of autologous stem cell transplant (ASCT). TP53 alterations are associated with inferior outcomes in MCL. The aim of this retrospective study is to determine treatment strategies and clinical outcomes in MCL patients based on TP53 gene mutation status. Methods: Retrospective data were collected from 19 institutions in the United States from 1/1993 to 1/2024. We examined treatment patterns and outcomes among MCL patients &gt;18 years of age with known TP53 mutation status by sequencing. Patients who did not receive treatment were excluded. The analysis was stratified based on presence of TP53 mutations. Systemic therapies were categorized as chemo-immunotherapy (CIT), non-chemotherapy (including monoclonal antibodies, lenalidomide, venetoclax, and novel agents on clinical trial), and regimens containing BTKi. The primary outcome was overall survival (OS) and secondary outcomes were progression free survival (PFS) and time to next treatment (TTNT). OS and PFS were estimated with the Kaplan-Meier method and log-rank tests were used to compare groups. Results: 645 patients were included in the study, with 468 men (72.6%) and median age was 64 years (range 30-89). 230/645 patients (35.7%) had a TP53 mutation, of which 182 (79%) were identified prior to 1L. While the male/female distribution was the same between the mutated and unmutated groups, median age at diagnosis and MIPI risk score was higher in the TP53 mutated group (age 65.9 vs 63.1 yrs, p= 0.015; MIPI 6.4 vs 6.1, p&lt;0.001). TP53 unmutated patients had a median of 1 line of therapy vs. 2 for the mutated group (p&lt;0.001, range 1-8). Blastoid histology and higher ki67 were also associated with the TP53 mutated group (p=0.045, 0.01 respectively) The median OS was 14.2 years for TP53 unmutated and 8.3 years for TP53 mutated patients (p&lt;0.0001). PFS in 1L was 0.95 years in TP53 mutated compared to 2.02 years in TP53 unmutated group (p&lt;0.0001). Selection of 1L therapeutic strategy was not associated with presence of TP53 mutation (Χ2 p= 0.21) although more patients in the TP53 unmutated group underwent ASCT (119/415 vs 38/230; Χ2 p=0.0006) TP53 mutation was associated with inferior survival compared to TP53 unmutated patients for CIT in 1L but the difference did not reach statistical significance when non-chemotherapy regimens and regimens containing BTKi were used. For CIT in 1L, 5 year OS was 78% [71-84%] for unmutated compared to 58% [48-67%] for the mutated group (p=0.0001 ). For non-chemotherapy regimens, 5 year OS for unmutated patients was 73% [52- 86%] compared to 52% [25-73%] for the mutated group (p=0.09). For regimens containing BTKi, 5 year OS for unmutated was 93% [81-97%] compared to 57% [28-78%] for mutated (p=0.07). Within the TP53 mutated group, there were no differences in any clinical outcomes between those receiving CIT, non-chemotherapy, or BTKi in 1L. While median OS appeared numerically longer in the BTKi group (14.4 yrs vs 8.8 yrs for CIT and 6.8 yrs for non-chemotherapy), the difference did not reach statistical significance (p=0.58). In contrast,TP53 unmutated patients who received CIT in 1L had better TTNT (p=0.0039) compared to those in non-chemotherapy and BTKi groups. There was no improvement in PFS (p=0.79) or OS (p=0.47). Conclusions To our knowledge this is the largest retrospective real world dataset of MCL treatment outcomes stratified by TP53 mutation. As in prior studies, TP53 mutation portends a worse prognosis in MCL compared to TP53 unmutated patients, but outcomes are better than historically reported. CIT in 1L was not associated with improved OS in either group. Irrespective of TP53 mutation status, incorporation of BTKi in first line was not associated with improved clinical outcomes. The gap in OS between TP53 mutated and unmutated MCL may be narrowing as treatment paradigms shift away from intensive induction chemotherapy and ASCT, and due to an increasing number of effective therapies for relapsed patients. Clinical trials of novel agents are needed to further improve the OS of TP53 mutated MCL patients.