Background: Primary mediastinal large B-cell lymphoma (PMBCL) is a distinct and aggressive subtype of large B-cell lymphoma that arises from thymic B-cells. (Blood PMID: 21700770). It primarily affects adolescents and young adults, with a notable female predominance, and typically presents as a bulky anterior mediastinal mass that can cause compressive symptoms. (Blood PMID: 32603413). Although PMBCL exhibits aggressive clinical behavior, it is highly responsive to modern chemoimmunotherapy regimens, with five-year overall survival rates ranging from 80% to 90%, particularly in the era of dose-adjusted EPOCH-R and PET-adapted strategies. (Sci Rep PMID: 35732790). Unlike other subtypes of aggressive B-cell lymphoma, PMBCL is biologically and clinically unique, sharing features with both classical Hodgkin lymphoma and diffuse large B-cell lymphoma, yet it remains underrepresented in clinical trials due to its rarity. While prior studies have demonstrated that disparities in care delivery - based on facility type, race/ethnicity, and socioeconomic status - can significantly influence cancer outcomes, these disparities have not been systematically examined in PMBCL. To our knowledge, this study represents the largest national analysis to date evaluating how demographic, socioeconomic, treatment, and survival differences in PMBCL may vary by treatment setting, comparing outcomes for patients treated at Academic Cancer Programs (ACPs) versus Community Cancer Programs (CCPs).Methods: We conducted a retrospective analysis of patients diagnosed with PMBCL in the United States between 2004 and 2022 using the National Cancer Database. Demographic, clinical, and survival data were compared between patients treated at ACPs and CCPs. ACPs included academic and research programs, including NCI-designated comprehensive cancer centers. CCPs comprised community, comprehensive community, and integrated network cancer programs. Kaplan-Meier and Cox proportional hazards models were used to compare overall survival (OS), adjusting for age, race/ethnicity, insurance status, comorbidity score (Charlson-Deyo), and distance from treating facility.Results: Of 3,533 patients identified, 1,378 (39%) had documented facility type and were included in this analysis: 864 (63%) were treated at ACPs and 514 (37%) at CCPs. Patients treated at ACPs were slightly younger (median age 50 vs. 51 years; p < 0.001) and included a higher proportion of Black (9.1% vs. 7.0%) and Hispanic (7.5% vs. 4.3%) patients (p < 0.001). ACPs cared for more patients from neighborhoods with low educational attainment (10% vs. 8%) and higher rates of Medicaid (8.4% vs. 6.0%) and uninsured status (2.2% vs. 1.6%). Median distance to care was shorter for ACP-treated patients (6.3 vs. 7.5 miles; p = 0.012). Stage II disease was the most common at diagnosis in both groups. Charlson–Deyo score ≥2 was observed in 5% of patients in both settings. Radiation therapy was more frequently used in CCPs (42% vs. 38%, p = 0.028), while time to chemotherapy initiation was similar (median 17 vs. 17.5 days). Two- and five-year OS were excellent across both cohorts: 90% and 87% for ACPs, versus 88% and 84% for CCPs (p = 0.21). Median OS was not reached in either group. In adjusted Cox models, treatment facility type was not independently associated with OS (HR 1.08, 95% CI 0.84–1.38; p = 0.56). Conclusions: In this national cohort, Academic Cancer Programs cared for a higher proportion of socioeconomically disadvantaged and racially diverse patients with PMBCL while achieving survival outcomes comparable to those of Community Cancer Programs. These findings support the role of academic centers as critical access points for vulnerable populations and demonstrate that excellent outcomes can also be achieved in community settings when care is timely and standardized. Further research is needed to understand which specific structural, clinical, or supportive care practices contribute to this parity, and to ensure all patients—regardless of geography or socioeconomic status—have equitable access to optimal lymphoma care.

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2025
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