Impact on survival through consolidation radiotherapy for diffuse large B-cell lymphoma: a comprehensive meta-analysis

Clinical Outcomes in Patients With DLBCL Treated With R-CHOP According to Radiotherapy and Interim PET Response

Background/Aim

Interim positron emission tomography/computed tomography (PET/CT) scan is a valuable tool for assessing the early metabolic response to chemotherapy in diffuse large B-cell lymphoma (DLBCL). Although radiotherapy is an effective treatment for lymphoma, especially for local tumor control, the role of consolidative radiotherapy in diffuse large B-cell lymphoma (DLBCL) remains controversial. This study analyzed the clinical outcomes of patients with DLBCL treated with rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP), stratified by interim PET response and the administration of radiotherapy.

Patients and Methods

We conducted a retrospective review of 107 patients with DLBCL treated with R-CHOP chemotherapy between January 2012 and December 2016. Overall survival (OS), recurrence-free survival (RFS), and freedom from disease progression (FFDP) were calculated using the Kaplan-Meier method and compared using the log-rank test.

Results

Forty-six patients were included in this analysis, with a median follow-up time of 65.9 months (range=4.7-125.3 months). The metabolic CR (mCR) group exhibited superior OS, RFS, and FFDP compared with the metabolic PR (mPR) group (p=0.003, p=0.001, and p=0.008, respectively). The 1-, 2-, and 5-year FFDP were 92.97%, 89.3%, and 85.6%, respectively, in the mCR group and 78.6%, 61.9%, and 44.2%, respectively, in the mPR group. In subgroup analysis, the FFDP of the mPR group without radiotherapy was significantly lower than that of the other groups (mCR with/without radiotherapy and mPR with radiotherapy, p=0.001).

Conclusion

Consolidative radiation therapy using interim PET can benefit patients who do not achieve mCR. Further well-controlled prospective randomized trials are required.

Long-Term Results of IFRT vs. ISRT in Infradiaphragmal Fields in Aggressive Non-Hodgkins's Lymphoma Patients-A Single Centre Experience

(1) Background: This study aimed to examine the difference in efficacy and toxicity of involved-field (IFRT) and involved-site radiotherapy (ISRT) fields in infradiaphragmal aggressive non-Hodgkin lymphoma patients. (2) Methods: In total, 140 patients with infradiaphragmal lymphoma treated between 2003 and 2020 were retrospectively evaluated. There were 69 patients (49%) treated with IFRT, and 71 (51%) patients treated with ISRT. The median dose in the IFRT group was 36 Gy, (range 4-50.4 Gy), and in the ISRT group, it was 30 Gy (range 4-48 Gy). (3) Results: The median follow-up in the IFRT group was 133 months (95% CI 109-158), and in the ISRT group, it was 48 months (95% CI 39-57). In the IFRT group, locoregional control was 67%, and in the ISRT group, 73%. The 2- and 5-year overall survival (OS) in the IFRT and ISRT groups were 79% and 69% vs. 80% and 70%, respectively (p = 0.711). The 2- and 5-year event-free survival (EFS) in the IFRT and ISRT groups were 73% and 68% vs. 77% and 70%, respectively (p = 0.575). Acute side effects occurred in 43 (31%) patients, which is more frequent in the IFRT group, 34 (39%) patients, than in the ISRT group, 9 (13%) patients, p > 0.01. Late toxicities occurred more often in the IFRT group of patients, (10/53) 19%, than in the ISRT group of patients, (2/37) 5%, (p = 0.026). (4) Conclusions: By reducing the radiotherapy volume and the doses in the treatment of infradiaphragmatic fields, treatment with significantly fewer acute and long-term side effects is possible. At the same time, efficiency and local disease control are not compromised.

Definition of bulky disease in early stage diffuse large B-cell lymphoma in computed tomography on coronal and transverse planes

Background

In early stage diffuse large B-cell lymphoma (ESDLBL), tumor bulkiness is an important determinant of treatment and prognosis. Tumor bulk is usually measured on transverse computed tomography (CT) plane and variably defined from 5 to 10 cm.

Objectives

Our study aims to investigate the prognostic significance of bulky disease measured on CT coronal and transverse planes and to evaluate the outcome of patients with bulky disease.

Methods

Patients with ESDLBL and treated with rituximab, cyclophosphamide, doxorubicin, and prednisolone (RCHOP) with or without radiotherapy were included. Receiver Operating Characteristic (ROC) analysis was used to identify the optimal tumor dimension that correlated with progression, relapse, or death. Correlation between different variables and progression-free survival (PFS) and overall survival (OS) were analyzed using log-rank (Mantel-Cox) test and Cox proportional hazard models.

Results

A total of 127 patients with a median age of 47 (range: 18-90) years were included. Eighty-two (64.6%) patients treated with combined modality treatment (CMT) [RCHOP + radiotherapy]. After a median follow-up of 40 (range: 2-114) months, 3-year PFS and OS were 83.9% (95% CI: 76.759%-89.981%), and 80.6% (95% CI: 72.499%-87.531%), respectively. Tumor dimension of >7.5 cm measured on either CT plane was the optimal cutoff point to define bulky disease. Three-year PFS and OS were inferior in the group of patients with no bulky disease on transvers plane (n = 84) but had bulky disease on coronal plane (n = 9,10.7%); (94.2% vs. 75%, p = 0.017 and 90.5% vs. 56.3%, p = 0.002), as well as in patients with no bulky disease on coronal plane (n = 89), but had bulky disease on transverse plane (n = 14, 15.7%); (94.1% vs. 62.3%, p < 0.001, and 90.4% vs. 63.5%, p = 0.002). Compared to RCHOP alone, 3-year PFS and OS were better in patients with bulky disease treated with CMT (78% vs. 52.5%, p = 0.018 and 81.8% vs. 38.7%, p = 0.003) but not in patients with non-bulky disease (96.2% vs. 93%, p = 0.691 and 87.6% vs. 91.5%, p = 0.477).

Conclusion

In ESDLBL, measurement of tumor mass on transverse and coronal CT planes may help in better identification of patients with bulky disease. The use of CMT was associated with better survival outcomes in patients with bulky disease.

PET/CT in Non-Hodgkin Lymphoma: An Update

Non-Hodgkin lymphomas represents a heterogeneous group of lymphoproliferative disorders characterized by different clinical courses, varying from indolent to highly aggressive. ¹⁸F-FDG-PET/CT is the current state-of-the-art diagnostic imaging, for the staging, restaging and evaluation of response to treatment in lymphomas with avidity for ¹⁸F-FDG, despite it is not routinely recommended for surveillance. PET-based response criteria (using five-point Deauville Score) are nowadays uniformly applied in FDG-avid lymphomas. In this review, a comprehensive overview of the role of ¹⁸F-FDG-PET in Non-Hodgkin lymphomas is provided, at each relevant point of patient management, particularly focusing on recent advances on diffuse large B-cell lymphoma and follicular lymphoma, with brief updates also on other histotypes (such as marginal zone, mantle cell, primary mediastinal- B cell lymphoma and T cell lymphoma). PET-derived semiquantitative factors useful for patient stratification and prognostication and emerging radiomics research are also presented.

Radiotherapy update: current role of radiotherapy in the treatment of lymphomas

Radiotherapy (RT) remains an important modality in the modern treatment of lymphomas. In Hodgkin lymphoma (HL), its role is stage-dependent. In early stage favorable HL, RT is an essential component of combined treatment. In early unfavorable and advanced stage HL, RT can be omitted if patients are positron emission tomography-computed tomography (PET-CT) negative after chemotherapy. In non-Hodgkin lymphomas (NHL), RT can be used as definitive treatment of indolent lymphoma. In aggressive NHL, the role of RT is limited to consolidation therapy of bulky disease, extranodal involvement and in elderly patients. Overall, technology evolved from extended fields to involved-node (INRT) and involved-site radiotherapy (ISRT), with concurrent reduction in doses. This short review summarizes current evidence and provides a future outlook with regard to the role of RT in the treatment of lymphomas.

DLBCL 1L—What to Expect beyond R-CHOP?

Simple Summary

Diffuse large B-cell lymphoma (DLBCL) is the most common aggressive non-Hodgkin’s lymphoma. About two-thirds of patients are cured by the first-line (1L) standard of care (SOC), the R-CHOP (Rituximab, Cyclophosphamide, Doxorubicin, Vincristine and Prednisolone) immunochemotherapy protocol. The profound molecular heterogeneity of DLBCL is the underlying reason why many patients, despite improved next-line options, eventually succumb to the disease. Hence, enhancing the efficacy of 1L treatment is critical for improving long-term outcomes in DLBCL. A plethora of novel treatment options with potential in later lines is currently under evaluation in 1L settings. We summarize here the established and emerging strategies for newly diagnosed DLBCL and emphasize the need for individualized treatment decisions.

Abstract

The R-CHOP immunochemotherapy protocol has been the first-line (1L) standard of care (SOC) for diffuse large B-cell lymphoma (DLBCL) patients for decades and is curative in approximately two-thirds of patients. Numerous randomized phase III trials, most of them in an “R-CHOP ± X” design, failed to further improve outcomes. This was mainly due to increased toxicity, the large proportion of patients not in need of more than R-CHOP, and the extensive molecular heterogeneity of the disease, raising the bar for “one-size-fits-all” concepts. Recently, an R-CHP regimen extended by the anti-CD79b antibody–drug conjugate (ADC) Polatuzumab Vedotin proved superior to R-CHOP in terms of progression-free survival (PFS) in the POLARIX phase III trial. Moreover, a number of targeted agents, especially the Bruton’s tyrosine kinase (BTK) inhibitor Ibrutinib, seem to have activity in certain patient subsets in 1L and are currently being tested in front-line regimens. Chimeric antigen receptor (CAR) T-cells, achieving remarkable results in ≥3L scenarios, are being exploited in earlier lines of therapy, while T-cell-engaging bispecific antibodies emerge as conceptual competitors of CAR T-cells. Hence, we present here the findings and lessons learnt from phase III 1L trials and piloting phase II studies in relapsed/refractory (R/R) and 1L settings, and survey chemotherapy-free regimens with respect to their efficacy and future potential in 1L. Novel agents and their mode of action will be discussed in light of the molecular landscape of DLBCL and personalized 1L perspectives for the challenging patient population not cured by the SOC.