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Background: Polatuzumab vedotin (Pola) is an antibody drug conjugate targeting CD79b that incorporates the microtubule disrupting monomethyl auristatin E payload. Pola was approved in 2023 for the upfront treatment of diffuse large B cell lymphoma (DLBCL) in combination with rituximab, cyclophosphamide, doxorubicin, and prednisone (polaRCHP) based on the POLARIX trial. However, the activity of pola appears to vary based on DLBCL cell of origin (COO) subtype, with greater efficacy in activated B cell (ABC) DLBCL compared to germinal center B cell (GCB) DLBCL (Russler-Germain Blood 2023). When outcomes in POLARIX are stratified by COO, polaRCHP demonstrated progression free survival (PFS) and overall survival (OS) benefits over RCHOP in patients with ABC but not GCB subtype DLBCL (PFS HR 0.34 ABC vs 1.03 GCB, OS HR 0.27 ABC vs 1.64 GCB; Morschhauser ASH 2023 and FDA data). Most prospective studies of pola used gene expression to assess COO, which is not readily clinically available. This study aims to examine if COO subtype by Hans algorithm (based on CD10, BCL6, and MUM1 expression by immunohistochemistry) is predictive of pola responses and outcomes in patients with large B cell lymphoma (LBCL). Methods: We conducted a retrospective, multicenter observational study of adults with LBCL who received pola (monotherapy or in combination) from 2015-2024 with Hans algorithm COO data and response assessment available. Patients were stratified by receipt of pola in the frontline vs relapsed/refractory (R/R) setting. The primary endpoint was overall response rate (ORR) to pola-based treatment in GCB vs non-GCB subtypes. Secondary endpoints included complete response rate (CRR), PFS, and OS. For time to event endpoints, patients responding to pola who received CAR T or stem cell transplantation prior to progression were censored at time of cellular therapy. Demographics were summarized by descriptive statistics. Comparative and survival analyses used Chi squared/Fischer exact tests and Kaplan Meier analysis. Data cutoff was July 1, 2024. Results: 718 patients were included. Median follow-up was 15 months (interquartile range [IQR] 8-32). Median age at LBCL diagnosis was 66 years (IQR 56-74); 62% were men; 69 (10%) had double hit lymphoma (DHL); 129 (18%) had underlying low grade lymphoma. Pola was used in the frontline setting in 293 (41%) patients, of whom 139 (47%) had GCB vs 154 (53%) non-GCB COO. Of the 426 patients receiving pola for R/R LBCL (including one patient receiving pola retreatment), 224 (53%) had GCB vs 202 (47%) non-GCB COO. Among patients receiving pola-based regimens in the R/R setting (GCB vs non-GCB: pola monotherapy = 7% vs 4%, pola + R = 26% vs 26%, pola + BR = 55% vs 61%, pola + other = 12% vs 9%; p = 0.44), the ORR in GCB vs non-GCB LBCL was 36% vs 61% (p < 0.001), while CRR in GCB vs non-GCB was 17% vs 36% (p < 0.001). COO remained a significant component of logistic multivariate regression models of ORR (p < 0.001) and CRR (p < 0.001) when incorporating IPI at original LBCL diagnosis, histology, DHL status, and refractory status to frontline therapy. Despite this, no significant PFS or OS differences by COO were seen, potentially due to approximately 1/4 patients being censored due to receiving subsequent cellular therapy (e.g. CAR T) prior to progression. In patients receiving frontline pola-based regimens (of which 275 [94%] included an anthracycline), ORR and CRR were similar in GCB vs non-GCB (ORR 89% vs 88% p > 0.5; CRR 76% vs 77% p > 0.5). While PFS and OS were similar between COO groups in the frontline cohort, follow-up and cohort size were limited. Conclusion: Based on this real-world evidence, COO classification by Hans algorithm is a strong predictor of the activity of pola-containing therapy in R/R LBCL, with significantly higher ORR and CRR in patients with non-GCB compared to GCB COO LBCL. This aligns with the cumulative existing evidence. ORR and CRR to pola-containing therapy in the frontline setting did not differ significantly by COO subtype, but longer follow-up of larger cohorts is needed to clarify the predictive role of COO by Hans algorithm in this setting, especially considering the PFS advantage with polaRCHP in POLARIX was not associated with significant differences in ORR or CRR. Overall, clinicians should consider factoring COO subtype into treatment decisions regarding pola-containing regimens, and studies of pola-based therapies should stratify patients and report outcomes by COO subtype.

Background Mantle cell lymphoma (MCL) is more common in males, with a male to female ratio of approximately 3:1. However, it is unclear whether disease characteristics and survival outcomes differ by sex. Additionally, the impact of race and ethnicity in MCL is understudied due to underrepresentation of minorities in clinical studies and trials. In this study, we utilized the National Cancer Database (NCDB) to examine patient and disease characteristics and survival outcomes of MCL by sex, race and ethnicity. Methods Patients diagnosed with MCL in 2004-2020 were identified from NCDB. Patient and disease characteristics were compared between groups using Chi-squared tests. Overall survival (OS) analysis was performed using the Kaplan-Meier method and the Cox proportional hazards model. Results A total of 35,135 patients was included. The median follow-up was 83.0 months (95% CI 81.9-84.1). 24,980 (71.1%) patients were male and 10,155 (28.9%) were female. Females had more elderly (age ≥65: 65.9% vs 59.0%; p<0.001), lower Charlson-Deyo Score (CDS ≥2: 7.0% vs 8.6%; p<0.001) and fewer stage III-IV diagnoses (80.5% vs 82.6%; p<0.001). Females were less likely to receive upfront treatment (80.7% vs 85.3%; p<0.001), treatment at academic centers (36.8% vs 40.9%; p<0.001) or transplant (11.0% vs 13.7%; p<0.001). Compared to males, females were more likely to live in metropolitan areas (83.7% vs 81.6%; p<0.001), had similar incomes, had more Medicare (60.4% vs 53.1%) and fewer private insurance (33.2% vs 38.6%; p<0.001). Female patients had better OS, with a median OS of 76.0 (95% CI 72.4-79.6) vs 67.8 months (95% CI 65.9-69.6; p<0.001). In the multivariable Cox model adjusting for age, race, ethnicity, CDS, stage, upfront treatment (vs surveillance or no treatment), facility (academic vs nonacademic), transplant, residence (metropolitan vs urban or rural) and insurance, female sex remained associated with superior OS (HR 0.84, 95% CI 0.793-0.890; p<0.001). For race, 32,399 (92.2%) patients were White, 1,465 (4.2%) were Black, 942 (2.7%) were others and 329 (0.9%) were unknown. Compared to White patients, Black patients had fewer elderly (52.9% vs 61.7%; p<0.001), higher CDS (≥2: 11.4% vs 7.9%; p<0.001), similar stage III-IV (80.7% vs 82.1%; p=0.276) and upfront treatment (84.7% vs 84.0%; p=0.074), were more likely to be treated at academic centers (50.6% vs 38.9%; p<0.001), were less likely to receive transplant (11.1% vs 13.0%; p=0.042), were more likely to live in metropolitan areas (91.0% vs 81.5%; p<0.001), had lower income, had more uninsured (4.4% vs 2.0%) and Medicaid (9.8% vs 3.7%) and fewer Medicare (47.4% vs 56.0%; p<0.001). Black and White patients had similar OS, with a median of 67.9 (95% CI 57.5-78.2) vs 69.6 months (95% CI 67.8 vs 71.3; p=0.697). In the multivariable Cox model, Black vs White race was not associated with OS (HR 1.086, 95% CI 0.952-1.240; p=0.219). For ethnicity, 31,717 (90.3%) patients were non-Hispanic, 1,894 (5.4%) were Hispanic and 1,534 (4.3%) were unknown. Hispanics had fewer elderly (51.3% vs 61.5%; p<0.001), lower CDS (≥2: 6.4% vs 8.2%; p=0.018), similar stage III-IV (81.2% vs 82.1%; p=0.467), were more likely to receive upfront treatment (86.0% vs 83.9%; p<0.001), more likely to be treated at academic centers (49.9% vs 39.5%; p<0.001), equally likely to receive transplant (13.0% vs 13.1%; p=0.943), more likely to live in metropolitan areas (95.4% vs 81.6%; p<0.001), had lower income, had more uninsured (9.6% vs 1.8%) and Medicaid (15.2% vs 9.6%) and fewer Medicare (40.3% vs 55.9%; p<0.001). Hispanics had better OS, with a median OS of 84.4 (95% CI 71.7-97.1) vs 70.5 months (95% CI 68.7-72.2; p<0.001). However, in the multivariable Cox model, Hispanic ethnicity was not associated with OS (HR 0.952, 95% CI 0.839-1.080; p=0.448). Conclusion This study is the first of its scale to demonstrate that female MCL patients have superior survival outcomes compared to males. It also demonstrated that neither Black race nor Hispanic ethnicity appears to be associated with worse survival outcomes. Despite its size, the NCDB is limited in the treatment information and disease characteristics it provides, including MIPI score, Ki-67, blastoid/pleomorphic morphology, and TP53 status. Thus, additional real-world dataset studies are needed to gain a deeper understanding of potential differences in sex, race and ethnicity with regards to disease characteristics and survival outcomes.

7080 Background: Primary mediastinal large B-cell lymphoma (PMBCL) is an uncommon type of aggressive B-cell non-Hodgkin lymphoma. PMBCL has distinct clinicopathologic features compared to diffuse large B-cell lymphoma but shares some clinical and biologic features with nodular sclerosis classic Hodgkin lymphoma (cHL). Central nervous system (CNS) relapse is exceedingly rare in cHL, therefore one may expect that CNS relapse in PMBCL is also uncommon. Herein, we examined the incidence of CNS relapse in patients with PMBCL. Methods: Patients with newly diagnosed PMBCL seen at Mayo Clinic between 1/2002 and 4/2023 were identified from the Mayo Clinic Lymphoma Database. Clinical features, treatment details and outcomes were abstracted from medical records. The CNS relapse rate was calculated using a competing risk model, with death considered as a competing risk. Results: A total of 154 PMBCL cases were identified. The median age at diagnosis was 38 years (range 18-77) and 60.4% were female. The distribution of CNS-IPI was low-risk in 80 (51.9%) patients, intermediate-risk in 43 (27.9%), and high-risk in 3 (1.9%), and data were missing for 28 patients (18.2%). 78 patients (50.6%) received R-CHOP and 76 patients (49.4%) received R-DA-EPOCH as frontline therapy. High-dose methotrexate (HD-MTX) for CNS prophylaxis was administered to 5 patients (all treated with R-CHOP). 20 patients received intrathecal (IT) chemotherapy (methotrexate and/or cytarabine) for CNS prophylaxis (4 with R-CHOP [1 received HD-MTX too],16 with R-DA-EPOCH). The median follow-up was 39 months (95% CI 28.2-49.8). Only 3 patients had CNS relapse, all associated with systemic relapse (1 concurrent, 1 had CNS relapse 8.8 months after systemic relapse, 1 had CNS relapse 2 months before systemic relapse). The cumulative incidence of CNS relapse for the entire cohort was 1.43% (95% CI 0.3%-4.6%) at 1 year and 2.21% (95% CI 0.6%-5.8%) at both 2 and 5 years. For those who did not receive CNS prophylaxis (n=130), the incidence was 0.86% (95% CI 0.1%-4.3%) at 1 year and 1.82% (95% CI 0.4%-5.8%) at both 2 and 5 years. All 3 patients who experienced CNS relapse had R-CHOP as frontline therapy; two patients did not receive any CNS prophylaxis, while 1 patient received IT CNS prophylaxis. Conclusions: The risk of isolated CNS relapse in PMBCL appears to be very low, even in patients who did not receive CNS prophylaxis. While some patients may experience CNS relapse associated with systemic relapse, the overall incidence was low (1.43% at 1 year and 2.21% at 2 and 5 years). The rarity of isolated CNS relapse in PMBCL suggests that routine CNS prophylaxis may not be necessary as part of initial therapy.

Background Primary mediastinal large B-cell lymphoma (PMBCL) is an uncommon type of non-Hodgkin lymphoma. Clinicopathologic features are distinct from diffuse large B cell lymphoma, but it shares some clinical and biologic features with Nodular sclerosis classic Hodgkin lymphoma. Central nervous system (CNS) relapse appears to be rare in patients with PMBCL, with limited literature reporting a rate of approximately 1.5% to 4%. We examined the incidence of CNS relapse, treatment approaches and survival outcomes in patients with PMBCL. Methods Patients with newly diagnosed PMBCL seen at Mayo Clinic between 2002 and 2022 were identified using the prospective Mayo Clinic Lymphoma Database. Clinical features, treatment details and outcomes were abstracted from the medical record. Cumulative incidence of CNS relapse was analyzed with death as a competing risk. The association of CNS-IPI, systemic treatment, and CNS prophylaxis approach with CNS relapse rate was analyzed using competing risk models and descriptively. Event-free survival (EFS) for the cohort was defined as time from PMBCL diagnosis to first recorded CNS and/or systemic relapse or death from any cause. Overall survival (OS) was defined as time from PMBCL diagnosis (or CNS relapse) to death from any cause. Survival analysis was performed using the Kaplan-Meier method. Results A total of 124 PMBCL cases were identified. The median age at diagnosis was 37 years and 61% were female. The distribution of CNS-IPI was low-risk in 67 (61%), intermediate-risk in 41 (37%), and high-risk in 2 (2%). 64 patients (52%) received R-CHOP and 54 patients (44%) received R-DA-EPOCH as frontline therapy. High-dose methotrexate (HD-MTX) for CNS prophylaxis was administered to 6 patients (5%), 5 with R-CHOP and 1 with R-DA-EPOCH. 16 patients received intrathecal (IT) chemotherapy (methotrexate and/or cytarabine) for CNS prophylaxis, 3 with R-CHOP and 13 with R-DA-EPOCH. The median follow-up was 56.0 months. The 5-year EFS rate was 75.1% and the 5-year OS rate was 90.7% for the entire cohort. 20 patients had systemic relapse only and 3 had CNS relapse. The cumulative incidence of CNS relapse was 1.84% (95% CI 0.46%-7.17%) at 2 years and 2.92% (95% CI 0.50%-8.84%) at 5 years (Figure 1). No statistically significant association of CNS-IPI, systemic therapy or CNS prophylaxis regimen with CNS relapse rate was found in competing risk models; however, this analysis was limited by a small event number (n=3). Among the 3 patients with CNS relapse, 1 had high-risk CNS-IPI and 2 had intermediate risk. All 3 patients were treated initially with R-CHOP. Two patients did not receive any CNS prophylaxis and 1 patient received IT CNS prophylaxis. All three patients who had CNS relapse were female. Patient #1 was diagnosed at age 48 and had simultaneous CNS and systemic relapse 6 months later. The patient was treated with HD-MTX, temozolomide and rituximab for CNS relapse, and subsequently received multiple therapies for systemic disease including R-DHAP, R-ICE, and died 17 months after CNS relapse. Patient #2 was diagnosed at age 22 and had CNS relapse after 8.7 months, followed by systemic relapse 2 months later. The patient received HD-MTX, temozolomide and rituximab for CNS relapse, followed by systemic and whole-brain radiation therapy (RT) for both systemic and CNS relapse. Subsequently the patient received salvage chemotherapy, autologous and allogeneic stem cell transplant for systemic relapse. The patient died 26.8 months after CNS relapse. Patient #3 was diagnosed at age 24 and had systemic relapse after 20.7 months, followed by CNS relapse 5.4 months later. The patient received methotrexate and whole-brain RT following CNS relapse and died 1.2 months after CNS relapse. Besides these 3 patients, we identified 6 PMBCL patients with CNS relapse who were diagnosed at other medical centers and subsequently referred to our institution for management of refractory disease. The survival after CNS relapse was poor, with a median OS of 10.4 months (95% CI 5.6-15.2). Conclusion Our study showed that the CNS relapse rate (1.84% at 2 years and 2.92% at 5 years) was overall low in patients with PMBCL, consistent with previous reports. CNS relapse was associated with poor survival despite aggressive treatment approaches. Novel approaches utilizing biological risk factors for CNS relapse, such as circulating tumor DNA, are needed to identify patients with CNS relapse.

Background The therapeutic landscape of mantle cell lymphoma (MCL) has evolved significantly since the early 2000s. We previously reported that a shift in frontline immunochemotherapy choices from 2002−2009 to 2010−2015 was associated with improved event-free survival and overall survival (OS) in both younger (age ≤65) and older (age >65) patients in a prospective Mayo Clinic/University of Iowa cohort (Castellino, Blood Advances, 2022). In addition, we recently reported that changes in treatment for relapsed/refractory (R/R) disease over the last two decades were associated with steady improvements in OS for R/R MCL (Tawfiq, ASH, 2022). In this study, we utilized data from the National Cancer Database (NCDB) to investigate the impact of therapy in the modern era on survival outcomes of patients with MCL in the US since 2004. Methods The NCDB is an outcomes database of more than 1,500 hospital-based cancer registries covering approximately 70% of newly diagnosed cancers in the US. The latest version of NCDB was used to identify patients with newly diagnosed MCL from 2004 to 2020. Three treatment eras were defined as Era 1 (2004−2009), Era 2 (2010−2014), and Era 3 (2015−2020), based on immunochemotherapy changes (from Era 1 to Era 2) and increased access to novel agents such as Bruton's tyrosine kinase (BTK) inhibitors (from Era 2 to Era 3). Overall survival between different eras was stratified and analyzed based on 3 age groups: <65, 65−79, and ≥80 years. Survival analysis was performed using the Kaplan-Meier method and all Cox proportional hazards models were adjusted for age and sex. Results A total of 32,746 patients with newly diagnosed MCL was identified, 12,847 (39.2%) patients were age <65, 14,297 (43.7%) age 65−79, and 5,602 (17.1%) age ≥80. For every age group, the distributions in sex, stage, Charlson-Deyo score, and treatment facility type (academic vs non-academic) were largely similar between eras. As expected, the median OS was significantly worse for patients age ≥80 years (19.8 months) compared to patients age 65-79 years (60.9 months) and patients age <65 years (143.9 months; p <0.001). In patients age <65 years, OS in Era 2 was improved when compared to Era 1, with a 5-year OS rate of 72.1% vs 67.6% (logrank p<0.001) (Figure 1) and an age- and sex-adjusted hazard ratio (HR) of 0.83 (95% CI 0.78−0.89, p<0.001). OS in Era 3 was similar to that in Era 2, with a 5-year OS rate of 72.2% vs 72.1% (logrank p=0.61) and an age- and sex-adjusted HR of 0.97 (95% CI 0.89−1.06, p=0.51). In patients age 65-79 years, similar trends in OS changes between eras were observed. The 5-year OS rate in Era 1, Era 2, and Era 3 was 43.3%, 52.8%, and 54.9%, respectively (p<0.001 comparing Era 2 vs Era 1, and p=0.05 comparing Era 3 vs Era 2). Age- and sex-adjusted HR was 0.83 (95% CI 0.78−0.87, p<0.001) comparing Era 2 vs Era 1 and 0.95 (95% CI 0.89−1.01, p=0.07) comparing Era 3 vs Era 2. In patients age ≥80 years, the improvement in OS from Era 1 to Era 2 was less prominent than other age groups. The 5-year OS rate was 22.9% vs 19.5% (p=0.03), and age- and sex-adjusted HR was 0.88 (95% CI 0.81−0.94, p<0.001). OS in Era 3 vs Era 2 was similar, with a 5-year OS rate of 23.1% vs 22.9% (logrank p=0.79) and an age- and sex-adjusted HR of 0.98 (95% CI 0.91−1.06, p=0.67). Conclusions This large NCDB study demonstrated that survival of patients with newly diagnosed MCL has improved over the last two decades. The results are consistent with our Mayo Clinic/University of Iowa prospective cohort study and confirm an improved OS after 2010, which was most likely driven by both frontline immunochemotherapy changes and better access to novel agents for R/R disease. The 5-year OS in patients diagnosed in 2015−2020 did not appear to be superior to those in 2010−2014, despite presumably having better access to novel agents such as BTK inhibitors in the R/R setting. This lack of a difference in OS may be partially due to short follow-up, but may also suggest that further improvement in frontline therapies by incorporating novel agents may be required to improve OS. The OS of patients age ≥80 years is limited and has only minimally improved after 2010, highlighting a significant unmet need for therapies with improved tolerability and efficacy in this age group.

Background Limited stage (stage I−II) disease is an uncommon presentation of mantle cell lymphoma (MCL), and its optimal management remains controversial. A British Columbia study (Leitch, Ann Oncol, 2003) and a Surveillance, Epidemiology and End Results (SEER) study (Murthy, Clin Lymphoma Myeloma Leuk, 2014) suggested the importance of radiotherapy (RT). A National Cancer Database (NCDB) study in the pre-BTK inhibitor (BTKi) era showed that chemotherapy (Chemo) plus RT (Chemo+RT) improved overall survival (OS) compared to Chemo or RT alone (Gill, Int J Radiat Oncol Biol Phys, 2015). However, a retrospective International Lymphoma Radiation Oncology Group study (Dabaja, Ann Oncol, 2017) reported comparable OS with Chemo+RT vs Chemo or RT alone. The potential differences in OS with different frontline therapy modalities may be modified by subsequent therapies for relapsed or refractory (R/R) disease. In this study, we used the NCDB data to analyze frontline treatment patterns and outcomes of limited stage MCL in the pre-BTKi vs BTKi eras. Methods The NCDB was queried to identify patients with stage I−II MCL diagnosed in 2004−2020. Because the first BTKi ibrutinib was approved by the FDA for R/R MCL in November 2013, we defined 2004−2013 as pre-BTKi era and 2014−2020 as BTKi era. Frontline treatment modalities were categorized to RT alone, Chemo alone, or Chemo+RT. Survival analysis was performed using the Kaplan-Meier method and the Cox proportional hazards model. Results Among 32,746 patients with newly diagnosed MCL in 2004−2020, 3,836 (11.7%) presented with stage I−II disease, with 2,428 having treatment information available. For patients diagnosed in the pre-BTKi era (n = 2005), 195 (9.7%) received RT alone, 1472 (73.4%) received Chemo alone, and 338 (16.9%) received Chemo+RT. For patients diagnosed in the BTKi era (n = 423), 45 (10.6%) received RT alone, 320 (75.7%) received Chemo alone, and 58 (13.7%) received Chemo+RT. Patients in the RT alone group were older (P <0.001) and had more females (P <0.001), but there were no statistically significant differences in Charlson-Deyo score, international prognostic index, or treating facility type (academic vs non-academic). For patients with stage I disease, in the pre-BTKi era, patients treated with Chemo+RT (n = 182) had improved OS compared to those treated with RT alone (n = 141) or Chemo alone (n = 647), with a 5-year OS of 75.4% vs 71.8% vs 61.4% (P <0.001). Similar results were observed in the BTKi-era, with a 5-year OS of 83.6% vs 69.5% vs 62.9% (P <0.001) for patients treated with Chemo+RT (n = 31), RT alone (n = 30), or Chemo alone (n = 130), respectively. After adjusting for age and sex, Chemo+RT was associated with improved OS compared to Chemo alone (pre-BTKi era, HR = 0.59, 95% CI = 0.46−0.75, P <0.001; BTKi era, HR = 0.34, 95% CI = 0.14−0.79, P = 0.013), but not compared to RT alone (pre-BTKi era, HR = 0.62, 95% CI = 0.23−1.68, P = 0.343; BTKi era, HR = 0.77, 95% CI = 0.56−1.05, P = 0.10) (Figure 1A). For patients with stage II disease, in the pre-BTKi era, patients treated with Chemo+RT (n = 156) had improved OS compared to those treated with RT alone (n = 54) or Chemo alone (n = 825), with a 5-year OS of 70.0% vs 47.3% vs 58.4% (P <0.001). In the BTKi-era, patients treated with Chemo+RT (n = 27) or RT alone (n = 15) both had improved OS compared to those treated with Chemo alone (n = 190), with a 5-year OS of 77.2% vs 78.8% vs 61.9% (P = 0.004) . After adjusting for age and sex, Chemo+RT was associated with improved OS compared to Chemo alone in BTKi era only (pre-BTKi era, HR = 0.85, 95% CI = 0.67−1.07, P = 0.165; BTKi era, HR = 0.49, 95% CI = 0.25−0.95, P = 0.034), but not compared to RT alone (pre-BTKi era, HR = 0.78, 95% CI = 0.53−1.13, P = 0.185; BTKi era, HR = 0.97, 95% CI = 0.35−2.67, P = 0.952) (Figure 1B). Conclusions Treatment pattern for limited stage MCL has not changed significantly from the pre-BTKi era to the BTKi era, with approximately 15% of patients receiving Chemo+RT, 10% RT alone and 75% Chemo alone. In the BTKi era, Chemo+RT appeared to be associated with better OS compared to Chemo alone but not compared to RT alone. Interpretation of the results requires caution because (1) patient numbers are small in Chemo+RT and RT alone groups, (2) longer follow-up may be needed, and (3) selection of therapy was not random, eg, patients receiving Chemo alone may have had higher disease burden such as bulky disease and/or non-contiguous stage II involvement but these details are not available in NCDB.