Radiation Therapy for Diffuse Large B-Cell Lymphoma: Indications, Outcomes, and Controversies

Patient Survival With and Without Radiation Therapy for Early-Stage Diffuse Large B-Cell Lymphoma in the Era of PET and Rituximab

Purpose

The benefit of radiation therapy (RT) becomes uncertain in the treatment of early stage diffuse large B-cell lymphoma (DLBCL) in the era of rituximab, positron emission topography (PET), and computed tomography (CT). We sought to retrospectively review modern patients with early stage I-II DLBCL treated with rituximab and staged by PET-CT to better define which patients benefit from consolidative RT.

Methods and Materials

Patients with early stage I-II DLBCL from 1998 to 2017 were reviewed coinciding with our institutional utilization of rituximab with the standard regimen of cyclophosphamide, doxorubicin, vincristine, and prednisone and PET-CT. Relevant clinical information was used to calculate National Comprehensive Cancer Network international prognostic index (IPI) scores. Kaplan-Meier survival analysis and a Cox proportional hazards model were used for overall survival (OS).

Results

Seventy-seven patients received chemoimmunotherapy alone, and 41 received chemoimmunotherapy plus RT. Median follow-up time was 9.5 years. On univariate analysis, extranodal disease (P = .04) and National Comprehensive Cancer Network IPI (P < .001) were significantly correlated with OS. Five-year OS was 87% versus 67%, and 10-year OS was 67% versus 58%, numerically higher favoring RT (P = .16). On multivariate Cox regression analysis of OS controlling for IPI and extranodal disease, the addition of RT was associated with improved OS (hazard ratio of 0.4, P = .01).

Conclusions

The current analysis supports the use of consolidative RT in early stage DLBCL given an OS benefit on multivariate analysis. Further prospective randomized data are needed to confirm these findings.

Efficacy of Palliative Radiation Therapy (RT) for Chemotherapy Relapsed or Refractory Diffuse Large B-Cell Lymphoma: A Population-Based Retrospective Review

PURPOSE

The study objective was to investigate the effectiveness of palliative radiation therapy (RT) for patients with diffuse large B-cell lymphoma (DLBCL) and to identify factors, such as chemotherapy relapsed/refractory (R/R) disease, that may influence RT outcomes.

METHODS AND MATERIALS

Patients with DLBCL who received palliative RT from 2001 to 2015 in British Columbia were reviewed for patient characteristics, treatment details, and outcomes. Univariable and multivariable analyses for response and local progression were performed.

RESULTS

Three-hundred and seventy courses of palliative RT in 217 patients were identified. Median equivalent dose in 2 Gy fractions was 19 Gy (range, 2-42 Gy). Clinical and/or radiologic response occurred in 230 (83%) of the 276 courses with response data available. Local control following palliative RT at 6 months was 66.7%. On univariable analysis, R/R disease was not associated with lower clinical response rates but had higher risk of progression (hazard ratio [HR], 0.5; P = .040). On multivariable analyses, patients with R/R disease who did not require concurrent steroids had greater response compared with those who received upfront palliative RT (odds ratio, 3.5; P = .011). Response to first-line chemotherapy and smaller lesion size were associated with improved local progression rates (HR, 0.2; P < .001 and HR, 0.5; P = .020, respectively). RT dose fractionation factors were not significant on any analyses.

CONCLUSIONS

Palliative RT for DLBCL is effective for symptom improvement, including in the chemotherapy R/R setting. Not requiring concurrent steroids, response to first-line chemotherapy, and smaller lesion size predicted better RT outcomes. There was no association between dose fractionation and response rates or local control to suggest that higher RT doses are more effective for palliation.

Hitting a Moving Target: Successful Management of Diffuse Large B-cell Lymphoma Involving the Mesentery With Volumetric Image-guided Intensity Modulated Radiation Therapy

INTRODUCTION

We report successful treatment of mesenteric diffuse large B-cell lymphoma (DLBCL) using localized involved site radiation therapy (ISRT), intensity modulated radiation therapy (IMRT), and daily computed tomography (CT)-image guidance.

PATIENTS AND METHODS

Patients with mesenteric DLBCL treated with RT between 2011 and 2017 were reviewed. Clinical and treatment characteristics were analyzed for an association with local control, progression-free survival (PFS), and overall survival.

RESULTS

Twenty-three patients were eligible. At diagnosis, the median age was 52 years (range, 38-76 years), and 57% (n = 13) had stage I/II DLBCL. All patients received frontline chemotherapy (ChT) (R-CHOP [rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone], n = 19; dose-adjusted R-EPOCH [rituximab, etoposide, prednisone, vincristine, cyclophosphamide, and doxorubicin], n = 4) with median 6 cycles. Prior to RT, salvage ChT for refractory DLBCL was given to 43% (n = 10) and autologous stem cell transplantation was administered in 13% (n = 3). At the time of RT, positron emission tomography-CT revealed 5-point scale of 1 to 3 (48%; n = 11), 4 (9%; n = 2), and 5 (44%; n = 10). All patients received IMRT, daily CT imaging, and ISRT. The median RT dose was 40 Gy (range, 16.2-49.4 Gy). Relapse or progression occurred in 22% (n = 5). At a median follow-up of 37 months, the 3-year local control, PFS, and overall survival rates were 80%, 75%, and 96%, respectively. Among patients treated with RT after complete metabolic response to frontline ChT (n = 8), the 3-year PFS was 100%, compared with 61% for patients with a history of chemorefractory DLBCL (n = 15; P = .055). Four of the 5 relapses occurred in patients with 5-point scale of 5 prior to RT (P = .127).

CONCLUSION

Mesenteric involvement of DLBCL can be successfully targeted with localized ISRT fields using IMRT and daily CT-image guidance.

Diffuse large B-cell lymphoma in very elderly patients over 80 years old: Incorporating consolidative radiation therapy into management decisions

Purpose

The population of patients aged 80 years or older who are diagnosed with diffuse large B-cell lymphoma (DLBCL) continues to increase, but an optimal treatment strategy has not been established. We sought to examine the influence of consolidative radiation therapy (RT) on outcome and toxicity among the very elderly diagnosed with stage I-IV DLBCL.

Methods and materials

We evaluated 131 patients treated at a single institution between 2002 and 2014 who were eligible for RT after successful treatment with chemotherapy.

Results

The median age was 83 years (range, 80-96). Advanced-stage disease was present in 61.8% of patients. Rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone was administered to 80% of patients (n = 108), and 23.7% of patients received consolidative RT. Among early-stage (ES) patients treated with 3 to 4 cycles of chemotherapy and RT (n = 12) versus 6 to 8 cycles of chemotherapy alone (n = 17), there were no statistically significant differences in 3-year disease-free, progression-free, or overall survival rates. The 3 year disease-free survival was 91.7% versus 88.2% among patients treated with combined modality therapy versus chemotherapy alone (P = .78). The 3-year overall survival was 82.5% versus 87.5% among patients treated with combined modality therapy compared with chemotherapy alone (P = .852). Anemia and neuropathy occurred more frequently among ES patients who received 6 to 8 cycles of chemotherapy alone. Among advanced-stage patients with bulky disease (n = 35), consolidative RT to sites of bulky disease may have improved local control (3-year local control, 100% vs 60.3%, P = .160).

Conclusions

Among patients aged 80 years or older who have with ES DLBCL, 3 to 4 cycles of chemotherapy followed by RT is at least equivalent in efficacy to chemotherapy alone and is associated with lower levels of toxicity, which suggests that it may be a better choice for therapy when trying to balance treatment efficacy and tolerability.