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Swinnen, Lode J.

Mayo Clinic

Johns Hopkins Kimmel Cancer Center

Citations 19

NCCN Guidelines® Insights: B-Cell Lymphomas 3.2025
Advani, Ranjana H. , Andreadis, B., Chang, Julie , Christian, Beth , deVos, Sven, Fayad, Luis , Hamid, Muhammad Saad , Hernandez‐Ilizaliturri, Francisco J. , Karimi, Yasmin , King, Rebecca L. , Krivacic, Susan, LaCasce, Ann S. , Messmer, Marcus , Rabinovitch, Rachel , Roberts, Kenneth B. , Saito, Naoyuki G. , Smith, Stephen D. , Swinnen, Lode J., Tuscano, Joseph M. , Dwyer, Mary A., Sundar, Hema, Advani, Ranjana H , Karimi, Yasmin H , Zelenetz, Andrew D. , Gordon, Leo I. , Abramson, Jeremy S. , Bartlett, Nancy L. , Budde, Lihua E. , Caimi, Paolo F. , Dholaria, Bhagirathbhai , Habermann, Thomas M. , Hu, Boyu , Kelsey, Chris R. , Kline, Justin Paul , Landsburg, Daniel J. , Lim, Megan S. , Ramakrishnan, Praveen , Reid, Erin G , Saeed, Hayder , Vose, Julie M.

Journal of the National Comprehensive Cancer Network | October 9, 2025 | Volume: 23 | Issue: 10 | Pages: No page available

10.6004/jnccn.2025.0048 Get It

The treatment landscape of B-cell lymphomas has significantly evolved in recent years with approval of novel targeted therapies. CD3 × CD20 bispecific antibodies and CD19-directed monoclonal antibodies and antibody–drug conjugates have demonstrated efficacy in relapsed/refractory follicular lymphoma (FL). Bruton tyrosine kinase (BTK) inhibitor–based regimens are emerging as effective treatment options for patients with TP53-mutated classical mantle cell lymphoma (MCL). Results from ongoing clinical trials suggest that the addition of CD3 × CD20 bispecific antibodies to chemoimmunotherapy improves outcomes in patients with relapsed/refractory diffuse large B-cell lymphoma (DLBCL). These NCCN Guideline Insights highlight significant updates to the NCCN Guidelines for B-Cell Lymphomas for the treatment of FL, MCL, and DLBCL.
Myeloablative vs nonmyeloablative consolidation for primary central nervous system lymphoma: results of Alliance 51101
Batchelor, Tracy T. , Giri, Sharmila, Ruppert, Amy S. , Geyer, Susan M. , Smith, Scott E. , Mohile, Nimish, Swinnen, Lode J., Friedberg, Jonathan W. , Kahl, Brad S. , Bartlett, Nancy L. , Cheson, Bruce D. , Wagner‐Johnston, Nina D. , Nayak, Lakshmi , Leonard, John P. , Rubenstein, James L. , Hsi, Eric D , Wagner-Johnston, Nina , Bartlett, Nancy L , Kahl, Brad S , Hsi, Eric D.

Blood Advances | April 10, 2024 | Volume: 8 | Issue: 12 | Pages: 3189-3199

10.1182/bloodadvances.2023011657 Get It

Abstract Although it is evident that standard-dose whole-brain radiotherapy as consolidation is associated with significant neurotoxicity, the optimal consolidative strategy for primary central nervous system lymphoma (PCNSL) is not defined. We performed a randomized phase 2 clinical trial via the US Alliance cancer cooperative group to compare myeloablative consolidation supported by autologous stem cell transplantation with nonmyeloablative consolidation after induction therapy for PCNSL. To our knowledge, this is the first randomized trial to be initiated that eliminates whole-brain radiotherapy as a consolidative approach in newly diagnosed PCNSL. Patients aged 18 to 75 years were randomly assigned in a 1:1 manner to induction therapy (methotrexate, temozolomide, rituximab, and cytarabine) followed by consolidation with either thiotepa plus carmustine and autologous stem cell rescue vs induction followed by nonmyeloablative, infusional etoposide plus cytarabine. The primary end point was progression-free survival (PFS). A total of 113 patients were randomized, and 108 (54 in each arm) were evaluable. More patients in the nonmyeloablative arm experienced progressive disease or death during induction (28% vs 11%; P = .05). Thirty-six patients received autologous stem cell transplant, and 34 received nonmyeloablative consolidation. The estimated 2-year PFS was higher in the myeloablative vs nonmyeloablative arm (73% vs 51%; P = .02). However, a planned secondary analysis, landmarked at start of the consolidation, revealed that the estimated 2-year PFS in those who completed consolidation therapy was not significantly different between the arms (86% vs 71%; P = .21). Both consolidative strategies yielded encouraging efficacy and similar toxicity profiles. This trial was registered at www.clininicals.gov as #NCT01511562.
Long-Term Follow-Up of the RESORT Study (E4402): A Randomized Phase III Comparison of Two Different Rituximab Dosing Strategies for Low–Tumor Burden Follicular Lymphoma
Kahl, Brad S. , Jegede, Opeyemi A. , Peterson, Christopher G., Swinnen, Lode J., Weiss, Matthias , Fishkin, Paul A. S., Fenske, Timothy S. , Williams, Michael E. , Weiss, Matthias , Fenske, Timothy S , Williams, Michael E , Jagede, Opeyemi A. , Kahl, Brad S , Peterson, Christopher, Habermann, Thomas M. , Schuster, Stephen J.

Journal of Clinical Oncology | January 9, 2024 | Volume: 42 | Issue: 7 | Pages: 774-778

10.1200/jco.23.01912 Get It

Clinical trials frequently include multiple end points that mature at different times. The initial report, typically based on the primary end point, may be published when key planned co-primary or secondary analyses are not yet available. Clinical trial updates provide an opportunity to disseminate additional results from studies, published in JCO or elsewhere, for which the primary end point has already been reported. In 2003, the Eastern Cooperative Oncology Group initiated a randomized phase III clinical trial (E4402) comparing two different rituximab dosing strategies for patients with previously untreated low–tumor burden follicular lymphoma. Rituximab-responsive patients (n = 299) were randomly assigned to either a retreatment rituximab (RR) strategy or a maintenance rituximab (MR) strategy. Each dosing strategy was continued until treatment failure. The primary end point of the study was time to treatment failure (TTF). In the original report, there was no difference in TTF between the two dosing strategies. Here, we report on the long-term outcomes for secondary end points of time to first cytotoxic therapy, duration of response, and overall survival (OS). At 7 years, 83% of MR patients had not required first chemotherapy compared with 63% of RR patients (hazard ratio, 2.37 [95% CI, 1.5 to 3.76]). At 7 years, 71% of MR remained in their first remission compared with 37% of RR patients. Despite the improved first remission length with MR, there was no difference in OS at 10 years (83% v 84%). With mature long-term data, we confirm that prolonged maintenance rituximab does not confer an OS advantage in low–tumor burden follicular lymphoma.
NCCN Guidelines® Insights: B-Cell Lymphomas, Version 6.2023
Advani, Ranjana H. , Andreadis, B., Chang, Julie , Christian, Beth , deVos, Sven, Fayad, Luis , Hamid, Muhammad Saad , Hernandez‐Ilizaliturri, Francisco J. , Kaminski, Mark , Karimi, Yasmin , King, Rebecca L. , Krivacic, Susan, LaCasce, Ann S. , Messmer, Marcus , Narkhede, Mayur , Rabinovitch, Rachel , Roberts, Kenneth B. , Smith, Stephen D. , Svoboda, Jakub , Swinnen, Lode J., Tuscano, Joseph M. , Dwyer, Mary A., Sundar, Hema, Advani, Ranjana H , Karimi, Yasmin H , Zelenetz, Andrew D. , Gordon, Leo I. , Abramson, Jeremy S. , Bartlett, Nancy L. , Budde, Lihua E. , Caimi, Paolo F. , Dholaria, Bhagirathbhai , Habermann, Thomas M. , Hu, Boyu , Kelsey, Chris R. , Lim, Megan S. , Ramakrishnan, Praveen , Reid, Erin G , Saeed, Hayder , Vose, Julie M.

Journal of the National Comprehensive Cancer Network | November 7, 2023 | Volume: 21 | Issue: 11 | Pages: 1118-1131

10.6004/jnccn.2023.0057 Get It

Novel targeted therapies (small molecule inhibitors, antibody–drug conjugates, and CD19-directed therapies) have changed the treatment landscape of relapsed/refractory B-cell lymphomas. Bruton’s tyrosine kinase (BTK) inhibitors continue to evolve in the management of mantle cell lymphoma (MCL), in both the relapsed/refractory and the frontline setting. Anti-CD19 CAR T-cell therapies are now effective and approved treatment options for relapsed/refractory follicular lymphoma (FL), diffuse large B-cell lymphoma (DLBCL), and MCL. Bispecific T-cell engagers represent a novel immunotherapeutic approach for relapsed FL and DLBCL after multiple lines of therapies, including prior CAR T-cell therapy. These NCCN Guideline Insights highlight the significant updates to the NCCN Guidelines for B-Cell Lymphomas for the treatment of FL, DLBCL, and MCL.
NCCN Guidelines® Insights: Central Nervous System Cancers, Version 2.2022
Baehring, Joachim M. , Butowski, Nicholas , Cannon, Donald M. , Chao, Samuel T. , Chheda, Milan G. , Fabiano, Andrew J. , Gigilio, Pierre, Hattangadi‐Gluth, Jona A. , Holdhoff, Matthias , Junck, Larry , Merrell, Ryan , Mrugała, Maciej M. , Nagpal, Seema , Nedzi, Lucien , Nevel, Kathryn , Patel, Toral , Peters, Katherine B. , Rockhill, Jason K., Rusthoven, Chad G. , Shonka, Nicole , Swinnen, Lode J., Weiss, Stephanie E. , Wen, Patrick Y. , Willmarth, Nicole E. , Bergman, Mary Anne, Darlow, Susan, Peters, Katherine B , Nagpal, Seema , Patel, Toral R , Horbinski, Craig , Nabors, Burt , Portnow, Jana , Bhatia, Ankush , Bloch, Orin G. , Brem, Steven , Forsyth, Peter A , Kaley, Thomas , Nghiemphu, Phioanh L. , Parney, Ian F. , Puduvalli, Vinay K. , Wen, Patrick Yung

Journal of the National Comprehensive Cancer Network | January 11, 2023 | Volume: 21 | Issue: 1 | Pages: 12-20

10.6004/jnccn.2023.0002 Get It

The NCCN Guidelines for Central Nervous System (CNS) Cancers focus on management of the following adult CNS cancers: glioma (WHO grade 1, WHO grade 2–3 oligodendroglioma [1p19q codeleted, IDH- mutant], WHO grade 2–4 IDH- mutant astrocytoma, WHO grade 4 glioblastoma), intracranial and spinal ependymomas, medulloblastoma, limited and extensive brain metastases, leptomeningeal metastases, non–AIDS-related primary CNS lymphomas, metastatic spine tumors, meningiomas, and primary spinal cord tumors. The information contained in the algorithms and principles of management sections in the NCCN Guidelines for CNS Cancers are designed to help clinicians navigate through the complex management of patients with CNS tumors. Several important principles guide surgical management and treatment with radiotherapy and systemic therapy for adults with brain tumors. The NCCN CNS Cancers Panel meets at least annually to review comments from reviewers within their institutions, examine relevant new data from publications and abstracts, and reevaluate and update their recommendations. These NCCN Guidelines Insights summarize the panel’s most recent recommendations regarding molecular profiling of gliomas.
Long Term Follow up of the Resort Study (E4402): A Randomized Phase III Study Comparing Two Different Rituximab Dosing Strategies for Low Tumor Burden Follicular Lymphoma
Peterson, Christopher G., Swinnen, Lode J., Weiss, Matthias , Fishkin, Paul A. S., Ehmann, W. Christopher, Fenske, Timothy S. , Williams, Michael E., Kahl, Brad S. , Hong, Fangxin , Peterson, Christopher, Habermann, Thomas M. , Schuster, Stephen J.

Blood | November 23, 2021 | Volume: 138 | Issue: Supplement 1 | Pages: 815-815

10.1182/blood-2021-152976 Get It

Abstract BACKGROUND: E4402 was a randomized phase III study comparing two different rituximab dosing strategies for patients with previously untreated, low tumor burden follicular lymphoma (FL). The primary endpoint was time to treatment failure. The initial publication (Kahl, JCO 2014) demonstrated that a retreatment strategy utilized less drug and produced comparable time to treatment failure compared to a maintenance strategy. Here we provide long term follow up results, focusing on response duration, time to first cytotoxic therapy, overall survival, and risk of histologic transformation. METHODS: Eligible patients had untreated, low tumor burden (GELF criteria) FL. Patients received R 375 mg/m 2 weekly x 4 and responders were randomized to maintenance rituximab (MR) (single dose R q 3 months) or retreatment rituximab (RR) (R weekly x 4 doses at disease progression). Each strategy was continued until treatment failure. The primary endpoint, time to treatment failure, was defined as progression within 6 months of last R, no response to R retreatment, initiation of alternative therapy, or inability to complete protocol therapy. Secondary endpoints included time to first cytotoxic therapy, quality of life and safety. The ECOG Data Monitoring Committee recommended release of study results at a planned interim analysis in September 2011 and patients and providers were notified of results. Time to treatment failure data collection halted with release of the results but limited data collection on time to first cytotoxic therapy, response duration, and risk of histologic transformation continued. INITITIAL RESULTS: From 11/03 to 9/08, 384 patients with FL were enrolled. Complete or partial response was achieved in 289 patients (71%), who were then randomized to MR (n=146) or RR (n=143). Demographic features were similar in the two arms: median age 59 years; ECOG PS 0-1 in all patients, and FLIPI low-risk (14.9 vs. 16.4%), intermediate-risk (46.3 vs. 42.9%) and high-risk (38.8 vs. 40.7%) for MR vs. RR, respectively. At initial publication, with a median follow-up of 3.8 years, the time to treatment failure was 3.9 years for MR vs. 3.6 years for RR (p=NS). LONG TERM FOLLOW UP RESULTS: Immunoglobulin levels and risks for serious infections/late complications in MR patients will be updated at the annual meeting. For the endpoint of time to first cytotoxic therapy, the median follow up is 8.7 years. At 7 years, 83% of MR and 63% of RR remained free from first cytotoxic therapy (HR 2.37; 95% CI 1.50 - 3.76) [Figure 1]. For the endpoint of response duration, the median follow up is 12.1 years. At 10 years, 66% of the MR patients remained in their 1 st remission compared to 30% of the RR patients who remained in their 1 st remission [Figure 2]. The median response duration for RR patients receiving a single 4-week course of rituximab was 3.25 years. There was no difference in the overall survival at 10 years, 84% for MR vs. 83% for RR. There was a trend towards a lower risk of histologic transformation for patients receiving MR (n = 4) compared to RR (n = 11) (p = 0.11). CONCLUSIONS: With long term follow up, the RESORT data indicates that in previously untreated, low tumor burden, follicular lymphoma, MR was superior to RR for delaying time to first cytotoxic therapy and for response duration, with a trend towards reducing the risk of histologic transformation. MR did not improve the overall survival. The original publication concluded that the time to treatment failure is similar between the two dosing strategies. Due to study design, time to treatment failure could not be analyzed in this long term follow up analysis. Compared to the historical benchmark of 3 years median time to first cytotoxic therapy when watch and wait is utilized, single agent rituximab, administered by either dosing strategy, was highly effective at delaying the time to first cytotoxic therapy. Figure 1 Figure 1. Disclosures Kahl: AbbVie, Adaptive, ADCT, AstraZeneca, Bayer, BeiGene, Bristol-Myers Squibb, Celgene, Genentech, Incyte, Janssen, Karyopharm, Kite, MEI, Pharmacyclics, Roche, TG Therapeutics, and Teva: Consultancy; AbbVie, Acerta, ADCT, AstraZeneca, BeiGene, Genentech: Research Funding. Habermann: Incyte: Other: Scientific Advisory Board; Tess Therapeutics: Other: Data Monitoring Committee; Seagen: Other: Data Monitoring Committee; Morphosys: Other: Scientific Advisory Board; Loxo Oncology: Other: Scientific Advisory Board; Eli Lilly & Co.,: Other: Scientific Advisor. Schuster: Abbvie: Consultancy, Research Funding; Acerta Pharma: Consultancy; AstraZeneca: Consultancy; Adaptive Biotechnologies: Research Funding; BeiGene: Consultancy; Celgene: Consultancy, Honoraria, Research Funding; DTRM: Research Funding; Genetech: Consultancy, Research Funding; Roche: Consultancy, Research Funding; Incyte: Research Funding; Juno Theraputics: Consultancy, Research Funding; Loxo Oncology: Consultancy; Merck: Research Funding; Nordic Nanovector: Consultancy; Novartis: Consultancy, Honoraria, Patents & Royalties, Research Funding; Pharmaclcyclics: Research Funding; Tessa Theraputics: Consultancy; TG Theraputics: Research Funding. Fenske: TG Therapeutics: Consultancy, Speakers Bureau; Servier Pharmaceuticals: Consultancy; Seattle Genetics: Speakers Bureau; Sanofi: Speakers Bureau; Pharmacyclics: Consultancy; MorphoSys: Consultancy; Kite (Gilead): Speakers Bureau; KaryoPharm: Consultancy; CSL Therapeutics: Consultancy; Bristol-Myers Squibb: Speakers Bureau; Biogen: Consultancy; Beigene: Consultancy; AstraZeneca: Speakers Bureau; ADC Therapeutics: Consultancy; Adaptive Biotechnologies: Consultancy; AbbVie: Consultancy.
NCCN Guidelines® Insights: B-Cell Lymphomas, Version 5.2021
Chang, Julie , Christian, Beth , Advani, Ranjana H. , Bartlett, Nancy L. , Vos, Sven de , Dholaria, Bhagirathbhai , Fakhri, Bita , Fayad, Luis , Glenn, Martha, Hernandez‐Ilizaliturri, Francisco J. , Kaminski, Mark , Krivacic, Susan, LaCasce, Ann S. , Narkhede, Mayur , Rabinovitch, Rachel , Roberts, Kenneth B. , Smith, Stephen D. , Svoboda, Jakub , Swinnen, Lode J., Tuscano, Joseph M. , Dwyer, Mary A., Sundar, Hema, Dholaria, Bhagirathbhai R , Bartlett, Nancy L , Advani, Ranjana H , Fakhri, Bita , Zelenetz, Andrew D. , Gordon, Leo I. , Abramson, Jeremy S. , Budde, Lihua E. , Caimi, Paolo F. , Habermann, Thomas M. , Hsi, Eric D. , Hu, Boyu , Kelsey, Chris R. , Khan, Nadia , Lim, Megan S. , Ramakrishnan, Praveen , Reid, Erin G , Saeed, Hayder , Vose, Julie M.

Journal of the National Comprehensive Cancer Network | November 15, 2021 | Volume: 19 | Issue: 11 | Pages: 1218-1230

10.6004/jnccn.2021.0054 Get It

In the last decade, a better understanding of the molecular pathogenesis of B-cell non-Hodgkin lymphomas has resulted in the development of novel targeted therapies, such as small molecule inhibitors of select kinases in the B-cell receptor pathway, antibody–drug conjugates, and small molecules that target a variety of proteins (eg, CD-19, EZH2, and XPO-1–mediated nuclear export). Anti-CD19 CAR T-cell therapy, first approved for relapsed/refractory (R/R) diffuse large B-cell lymphoma, has also emerged as a novel treatment option for R/R follicular lymphoma and mantle cell lymphoma. These NCCN Guideline Insights highlight the new targeted therapy options included in the NCCN Guidelines for B-Cell Lymphomas for the treatment of R/R disease.
Challenges in the Treatment of Newly Diagnosed and Recurrent Primary Central Nervous System Lymphoma
Holdhoff, Matthias , Mrugała, Maciej M. , Swinnen, Lode J., Perez-Heydrich, Carlos A. , Nayak, Lakshmi , Grommes, Christian , Kaley, Thomas

Journal of the National Comprehensive Cancer Network | November 5, 2020 | Volume: 18 | Issue: 11 | Pages: 1571-1578

10.6004/jnccn.2020.7667 Get It

Primary central nervous system lymphomas (PCNSLs) are rare cancers of the central nervous system (CNS) and are predominantly diffuse large B-cell lymphomas of the activated B-cell (ABC) subtype. They typically present in the sixth and seventh decade of life, with the highest incidence among patients aged >75 years. Although many different regimens have demonstrated efficacy in newly diagnosed and relapsed or refractory PCNSL, there have been few randomized prospective trials, and most recommendations and treatment decisions are based on single-arm phase II trials or even retrospective studies. High-dose methotrexate (HD-MTX; 3–8 g/m2) is the backbone of preferred standard induction regimens. Various effective regimens with different toxicity profiles can be considered that combine other chemotherapies and/or rituximab with HD-MTX, but there is currently no consensus for a single preferred regimen. There is controversy about the role of various consolidation therapies for patients who respond to HD-MTX–based induction therapy. For patients with relapsed or refractory PCNSL who previously experienced response to HD-MTX, repeat treatment with HD-MTX–based therapy can be considered depending on the timing of recurrence. Other more novel and less toxic regimens have been developed that show efficacy in recurrent disease, including ibrutinib, or lenalidomide ± rituximab. There is uniform agreement to delay or avoid whole-brain radiation therapy due to concerns for significant neurotoxicity if a reasonable systemic treatment option exists. This article aims to provide a clinically practical approach to PCNSL, including special considerations for older patients and those with impaired renal function. The benefits and risks of HD-MTX or high-dose chemotherapy with autologous stem cell transplantation versus other, better tolerated strategies are also discussed. In all settings, the preferred treatment is always enrollment in a clinical trial if one is available.
Central Nervous System Cancers, Version 3.2020, NCCN Clinical Practice Guidelines in Oncology
Ahluwalia, Manmeet S. , Baehring, Joachim M. , Brem, Henry , Butowski, Nicholas , Campian, Jian , Clark, Stephen W. , Fabiano, Andrew J. , Hattangadi‐Gluth, Jona A. , Holdhoff, Matthias , Junck, Larry , Kumthekar, Priya , Loeffler, Jay S., Mrugała, Maciej M. , Nagpal, Seema , Pandey, Manjari , Peters, Katherine B. , Robins, Ian, Rockhill, Jason K., Rusthoven, Chad G. , Shonka, Nicole , Shrieve, Dennis C. , Swinnen, Lode J., Weiss, Stephanie E. , Wen, Patrick Y. , Willmarth, Nicole E. , Bergman, Mary Anne, Darlow, Susan, Peters, Katherine B , Ahluwalia, Manmeet S , Nagpal, Seema , Nabors, Burt , Portnow, Jana , Brem, Steven , Forsyth, Peter A , Horbinski, Craig , Kaley, Thomas , Parney, Ian F. , Puduvalli, Vinay K. , Wen, Patrick Yung

Journal of the National Comprehensive Cancer Network | November 5, 2020 | Volume: 18 | Issue: 11 | Pages: 1537-1570

10.6004/jnccn.2020.0052 Get It

The NCCN Guidelines for Central Nervous System (CNS) Cancers focus on management of adult CNS cancers ranging from noninvasive and surgically curable pilocytic astrocytomas to metastatic brain disease. The involvement of an interdisciplinary team, including neurosurgeons, radiation therapists, oncologists, neurologists, and neuroradiologists, is a key factor in the appropriate management of CNS cancers. Integrated histopathologic and molecular characterization of brain tumors such as gliomas should be standard practice. This article describes NCCN Guidelines recommendations for WHO grade I, II, III, and IV gliomas. Treatment of brain metastases, the most common intracranial tumors in adults, is also described.
Positron Emission Tomography–Directed Therapy for Patients With Limited-Stage Diffuse Large B-Cell Lymphoma: Results of Intergroup National Clinical Trials Network Study S1001
Persky, Daniel O. , Li, Hongli , Stephens, Deborah M. , Park, Steven I., Bartlett, Nancy L. , Swinnen, Lode J., Winegarden, Jerome D., FitzGerald, Thomas J. , Leonard, John P. , Song, Joo Y. , Fisher, Richard I., Smith, Sonali M. , Miller, Thomas P. , Friedberg, Jonathan W. , Park, Steven , Song, Joo Y , Bartlett, Nancy L , FitzGerald, Thomas J , Park, Steven I , Stephens, Deborah M , Barr, Paul M. , Constine, Louis S , Kahl, Brad S. , LeBlanc, Michael , Rimsza, Lisa M.

Journal of Clinical Oncology | July 13, 2020 | Volume: 38 | Issue: 26 | Pages: 3003-3011

10.1200/jco.20.00999 Get It

PURPOSEDiffuse large B-cell lymphoma (DLBCL) presents as a limited-stage disease in 25% to 30% of patients, with better overall survival (OS) than that for advanced-stage disease but with continuous relapse regardless of treatment approach. The preferred treatment is abbreviated rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP) and radiation therapy. On the basis of promising results of positron emission tomography (PET)–directed treatment approaches, we designed a National Clinical Trials Network (NCTN) study to improve outcomes and decrease toxicity.METHODSPatients with nonbulky (< 10 cm) stage I/II untreated DLBCL received 3 cycles of standard R-CHOP therapy and underwent a centrally reviewed interim PET/computed tomography scan (iPET). Those with a negative iPET proceeded with 1 additional cycle of R-CHOP, whereas those with a positive iPET received involved field radiation therapy followed by ibritumomab tiuxetan radioimmunotherapy.RESULTSOf 158 patients enrolled, 132 were eligible and 128 underwent iPET, which was positive in 14 (11%) of the patients. With a median follow-up of 4.92 years (range, 1.1-7.7 years), only 6 patients progressed and 3 died as a result of lymphoma. Eleven patients died as a result of nonlymphoma causes at a median age of 80 years. The 5-year progression-free survival estimate was 87% (95% CI, 79% to 92%) and the OS estimate was 89% (95% CI, 82% to 94%), with iPET-positive and iPET-negative patients having similar outcomes.CONCLUSIONTo our knowledge, S1001 is the largest prospective study in the United States of limited-stage DLBCL in the rituximab era, with the best NCTN results in this disease subset. With PET-directed therapy, 89% of the patients with a negative iPET received R-CHOP × 4, and only 11% had a positive iPET and required radiation, with both groups having excellent outcomes. The trial establishes R-CHOP × 4 alone as the new standard approach to limited-stage disease for the absolute majority of patients.