The rationale and role of radiation therapy in the treatment of patients with diffuse large B-cell lymphoma in the Rituximab era

PET-guided treatment for personalised therapy of Hodgkin lymphoma and aggressive non-Hodgkin lymphoma

FDG-PET scanning has a central role in lymphoma staging and response assessment. There is a growing body of evidence that PET response assessment during and after initial systemic therapy can provide useful prognostic information, and PET response has an evolving role in guiding patient care. This review provides a perspective on the role of PET response assessment for individualised management of patients with the most common aggressive lymphomas, Hodgkin lymphoma and diffuse large B-cell lymphoma.

Long-term results of PET-guided radiation in patients with advanced-stage diffuse large B-cell lymphoma treated with R-CHOP

Consolidative radiation therapy (RT) for advanced-stage diffuse large B-cell lymphoma (DLBCL) remains controversial, with routine practice continuing to include RT in patients with initial bulky disease or residual masses. Positron emission tomography (PET)-computed tomography is a sensitive modality for detecting the presence of residual disease at the end of treatment (EOT). A PET-guided approach to selectively administering RT has been the policy in British Columbia since 2005. Patients with advanced-stage DLBCL diagnosed from 1 January 2005 to 1 March 2017 and treated with at least 6 cycles of R-CHOP (cyclophosphamide, doxorubicin, vincristine, and prednisolone plus rituximab), who underwent EOT PET, were included in this analysis. Those with complete metabolic response (PET-negative [PET-NEG]) were observed; those with PET-positive (PET-POS) scans were offered consolidative RT, when feasible. Of the patient records reviewed, 723 were identified, with median follow-up of 4.3 years: 517 (72%) were PET-NEG; 206 (28%) were PET-POS. Time to progression (TTP) and overall survival (OS) at 3 years were 83% vs 56% and 87% vs 64%, in patients with PET-NEG and PET-POS scans, respectively. PET-POS patients with nonprogressing disease treated with consolidative RT (109 and 206; 53%) had outcomes approaching those of PET-NEG patients, with 3-year estimates of 76% and 80% for TTP and OS. PET-NEG patients who had bulky disease (≥10 cm) at diagnosis had outcomes indistinguishable from those without bulk, despite the omission of RT. These data suggest that patients with advanced-stage DLBCL who are PET-NEG at EOT and receive no RT have excellent outcomes. 18F-fluorodeoxyglucose-PET can reliably guide selective administration of consolidative RT, even in patients with initially bulky disease.

Radiotherapy for early stage diffuse large B-cell lymphoma with or without double or triple hit genetic alterations

We investigated whether adding radiation (RT) to systemic therapy improved outcomes in early stage diffuse large B-cell lymphoma (DLBCL) patients with or without double- or triple-hit lymphoma (DHL/THL) biology. This analysis included 183 patients profiled with fluorescent in situ hybridization (FISH) for alterations in MYC, BLC2, and/or BCL6. A total of 146 (80%) were non-DHL/THL, 27 (15%) were DHL, and 10 (6%) were THL. Systemic therapy without RT resulted in inferior freedom from relapse (FFR) (HR: 2.28; 95% CI, 1.10-4.77; p = .02). The median FFR for non-DHL/THL was not reached and was 33 and 22.3 months for DHL and THL, respectively; p < .001. Low-risk (R-IPI <2) DHL/THL patients treated with rituximab-based therapy had 3-year FFR rates of 11% and 71% for systemic therapy without and with RT, respectively; p = .04. No differences in overall survival were observed between the treatment groups. Treatment intensification with RT may improve early stage DHL/THL outcomes.

Consolidation radiotherapy for advanced-stage aggressive B-cell non-Hodgkin lymphoma: A systematic review and meta-analysis

Patients with advanced aggressive B-cell non-Hodgkin lymphomas (NHL) are usually treated with rituximab in combination with chemotherapy. However, disease relapse rates are high. Radiotherapy (RT) has been shown to be efficacious in treating early-stage NHL but its role in advanced stage diseases is unclear. We performed a systematic review of randomized controlled trials (RCTs) comparing chemotherapy with RT to chemotherapy alone in patients with newly diagnosed advanced aggressive NHL. We searched online databases and pooled similar outcome estimates. For time-to-event outcomes, we estimated hazard ratios (HR) for overall survival (OS) and event-free survival (EFS) using the fixed-effect model. Two RCTs involving 254 patients met inclusion criteria. The trials were single-centre RCTs with follow-up period of five and ten years. Both trials were conducted in the pre-rituximab era. Patients treated with consolidation RT had better OS (HR for mortality 0.61; 95 % CI 0.38 to 0.97) and EFS (HR for mortality 0.67; 95 % CI 0.46 to 0.98) compared to those who received no RT. There was an apparent benefit of RT on local control (OR 0.09; 95 % CI 0.04 to 0.20); although this was estimated as a dichotomous rather than time-to-event outcome. Limited evidence shows benefits of consolidation RT in advanced aggressive NHL. However, we were not able to estimate the effect size with confidence due to small number of trials and sample size. We cannot recommend routine consolidation RT in advanced aggressive NHL. More RCTs with the inclusion of rituximab and PET-CT monitoring are needed.

Interobserver variability in clinical target volume delineation for primary mediastinal B-cell lymphoma

PURPOSE

The purpose of this study was to evaluate interobserver variability among radiation oncologists with experience in the field of lymphoma radiation therapy in the delineation of clinical target volume (CTV) in a challenging case of primary mediastinal B-cell lymphoma.

METHODS AND MATERIALS

Ten experienced radiation oncologists were invited to a 1-day contouring session. The case of a 56-year-old man with primary mediastinal B-cell lymphoma with complete metabolic response after chemotherapy was chosen as the sample for the study. A brief presentation of his clinical history was given, together with guidelines for contouring. The 10 CTVs obtained were then compared in terms of variation in total volume and in craniocaudal, laterolateral, and anteroposterior diameters. The CTV with the best Dice similarity coefficient (DSC) between the union of all 10 CTVs and the individual CTV was considered the reference CTV, and the DSC and the Hausdorff distance (HD) for each volume compared with the reference CTV were then calculated.

RESULTS

A significant variability was found in total volume (mean, 498.3 cm(3); range, 181.8-1003 cm(3)) and craniocaudal (median, 144.7 mm; range, 80.6-159 mm), laterolateral (median, 133.5 mm; range, 83.7-149.5 mm), and anteroposterior diameters (median, 136.2 mm; range, 84-150.5 mm). Analysis of the DSC and the HD showed a mean DSC of 0.53 (range, 0.31-0.74) and a mean HD of 6.4 cm (range, 1.8-14.8 cm).

CONCLUSIONS

Results of this study strongly indicate the need to develop and share appropriate contouring guidelines among experts and suggest the promotion of specific educational activities to improve radiation therapy quality in both clinical trials and routine clinical practice.

Treatment of diffuse large B-cell lymphoma in the elderly: regimens without anthracyclines are common and not futile

Anthracycline-containing regimens (ACRs) are recommended for patients with diffuse large B-cell lymphoma (DLBCL). However, over 40% of elderly patients do not receive ACRs, possibly due to expected toxicities. We characterized treatment choices and compared the 3-year overall survival (OS) rates of 8262 Medicare beneficiaries diagnosed with DLBCL in 2000-2006 identified from the Surveillance, Epidemiology, and End Results (SEER)-Medicare linked database. Of the cohort, 45% had ACR with rituximab (ACR-R), 13% had ACR without R, 6% had non-ACR with R (non-ACR-R), 4% had R monotherapy, 3% had non-ACR and 29% had no systemic therapy. Patients not receiving ACR were older and/or had more comorbidities. The unadjusted OS was highest in ACR-R (65%), followed by ACR without R (55%) and non-ACR-R (44%). After adjusting patient covariates, ACR-R showed the best survival (63%). However, OS was comparable between non-ACR-R (52%) and ACR without R (52%). Non-ACR-R could be considered for patients who are poor candidates for ACR.

Reduction of the treated volume to involved node radiation therapy as part of combined modality treatment for early stage aggressive non-Hodgkin's lymphoma

BACKGROUND AND PURPOSE

This retrospective study investigated whether focused involved node radiation therapy (INRT) can safely replace involved field RT (IFRT) in patients with early stage aggressive NHL.

PATIENTS AND METHODS

We included 258 patients with stage I/II aggressive NHL who received combined modality treatment (87%) or primary RT alone (13%). RT consisted of a total dose of 30-40 Gy in 15-20 fractions IFRT or INRT. We compared survival, relapse pattern, radiation-related toxicity and quality of life for both RT techniques.

RESULTS

Type of RT was not related to the outcome in either the uni- or multivariate survival analysis. Relapses developed in 59 of 252 patients (23%) of which 47 (80%) were documented as distant recurrence only. Failure of the INRT technique was noted in one patient. There was no significant difference in acute radiation-related toxicity between RT-groups but IFRT showed a significantly higher incidence of higher grade toxicities. Patients treated with INRT had a significantly better physical functioning and global quality of life compared to the IFRT group.

CONCLUSIONS

Given the retrospective nature of this study, no solid conclusions can be drawn. However, in view of the equivalent efficacy and more favorable toxicity profile, the replacement of IFRT by INRT in combination with chemo-(immuno)-therapy looks very attractive for patients with early stage aggressive NHL.

Radiation therapy in primary mediastinal B-cell lymphoma with positron emission tomography positivity after rituximab chemotherapy

PURPOSE

To investigate the role of radiation therapy (RT) in patients affected with primary mediastinal B-cell lymphoma (PMBCL) with residual (18)fluorodeoxyglucose positron emission tomography ((18)FDG-PET)-positive disease after rituximab chemotherapy (R-CT).

METHODS AND MATERIALS

Thirty-seven patients treated with R-CT and RT, all with (18)FDG-PET scan at diagnosis and before RT, were included. All (18)FDG-PET scans were reviewed, and responses were classified according to the Deauville 5-point scoring system. Outcomes measures were overall survival (OS) and progression-free survival (PFS), estimated for the whole cohort and for subgroups according to (18)FDG-PET score after R-CT.

RESULTS

The median follow-up time was 40.9 months. Three patients were assigned to Deauville score 1 (8.1%), 9 to score 2 (24.3%), 7 to score 3 (19%), 14 to score 4 (37.8%), and 4 to score 5 (10.8%). After RT, all patients with score 3-4 experienced a complete response (CR). Among patients with score 5, 1 was in CR (25%), 2 had persistent positivity (50%), and 1 showed progressive disease (25%). A total of 4 patients experienced progression or relapse: 1 of 33 (3%) with scores 1-4, and 3 of 4 (75%) with score 5. The 3-year OS and PFS of the whole cohort were 89.8% and 88.7%, respectively. OS was significantly different between scores 1-3 and scores 4-5 (100% vs 77% at 3 years, P<.05). Patients with a score of 5 had a significantly worse outcome than did all other patients (OS at 2 years, 33.3% vs 100%).

CONCLUSIONS

Approximately 50% of PMBCL patients show residual disease at (18)FDG-PET scan after R-CT. RT is able to convert to CR approximately 85% of these patients, but those with a Deauville score of 5 (10%) appear at high risk of progression and death, and they might be candidates for intensified programs.

Is there a role for consolidative radiotherapy in the treatment of aggressive and localized non-Hodgkin lymphoma? A systematic review with meta-analysis

BACKGROUND

Chemotherapy is the mainstay of non-Hodgkin lymphoma (NHL) treatment. Based on expert opinion, the use of radiotherapy (RT) is currently preferred in some institutions as consolidative treatment for patients with localized disease. The lack of conclusive data coming from conflicting studies about the impact of treatment demands a systematic review, which could provide the most reliable assessment for clinical decision-making. We evaluate the addition of RT post-CT, for aggressive and localized NHL (ALNHL).

METHODS

Randomized controlled trials (RCT) that evaluated chemotherapy alone versus chemotherapy plus RT were searched in databases. The outcomes were overall survival (OS), progression-free survival (PFS), overall response rate (ORR) and toxicity. Risk ratio (RR) and hazard ratio (HR) with their respective 95% confidence intervals (CI) were calculated using a fized-effect model.

RESULTS

Four trials (1,796 patients) met the inclusion criteria. All trials tested the use of RT after systemic therapy comprising anthracycline-based chemotherapy. This systematic review showed that RT enhances PFS after chemotherapy (hazard ratio [HR] 0.81; 95% CI 0.67-0.98; p = 0.03), with no impact on ORR and OS. Some heterogeneity between trials could limit the conclusions about OS. Toxicity data could not be pooled due to differences in reporting adverse events.

CONCLUSIONS

This systematic review with meta-analysis shows no improvement in survival when adding RT to systemic therapy for ALNHL. Our conclusions are limited by the available data. Further evaluations of new RT technologies and its association with biologic agents are needed.

Radiotherapy and "new" drugs-new side effects?

BACKGROUND AND PURPOSE

Targeted drugs have augmented the cancer treatment armamentarium. Based on the molecular specificity, it was initially believed that these drugs had significantly less side effects. However, currently it is accepted that all of these agents have their specific side effects. Based on the given multimodal approach, special emphasis has to be placed on putative interactions of conventional cytostatic drugs, targeted agents and other modalities. The interaction of targeted drugs with radiation harbours special risks, since the awareness for interactions and even synergistic toxicities is lacking. At present, only limited is data available regarding combinations of targeted drugs and radiotherapy. This review gives an overview on the current knowledge on such combined treatments.

MATERIALS AND METHODS

Using the following MESH headings and combinations of these terms pubmed database was searched: Radiotherapy AND cetuximab/trastuzumab/panitumumab/nimotuzumab, bevacizumab, sunitinib/sorafenib/lapatinib/gefitinib/erlotinib/sirolimus, thalidomide/lenalidomide as well as erythropoietin. For citation crosscheck the ISI web of science database was used employing the same search terms.

RESULTS

Several classes of targeted substances may be distinguished: Small molecules including kinase inhibitors and specific inhibitors, antibodies, and anti-angiogenic agents. Combination of these agents with radiotherapy may lead to specific toxicities or negatively influence the efficacy of RT. Though there is only little information on the interaction of molecular targeted radiation and radiotherapy in clinical settings, several critical incidents are reported.

CONCLUSIONS

The addition of molecular targeted drugs to conventional radiotherapy outside of approved regimens or clinical trials warrants a careful consideration especially when used in conjunction in hypo-fractionated regimens. Clinical trials are urgently needed in order to address the open question in regard to efficacy, early and late toxicity.

Randomized clinical trial to assess the efficacy of radiotherapy in primary mediastinal large B-lymphoma

PURPOSE

We developed a controlled clinical trial to assess the efficacy and toxicity of adjuvant-involved field radiotherapy (IFRT) in patients with primary mediastinal B-cell lymphoma that achieved complete response after the patients were treated with cyclophosphamide, doxorubicin, vincristine, prednisone, and rituximab (R-CHOP-14).

METHODS AND MATERIALS

Between January 2001 and June 2004, 124 consecutive patients who were in complete remission after dose dense chemotherapy and rituximab administration (R-CHOP14) were randomly assigned to received IFRT (30 Gy). Sixty-three patients received IFR, and 61 patients did not (control group).

RESULTS

The study aimed to include 182 patients in each arm but was closed prematurely because in a security analysis (June 2004), progression and early relapse were more frequent in patients that did not received IFRT. Patients were followed until March 2009, at which point actuarial curves at 10 years showed that progression free-survival was 72% in patients who received IFR and 20% in the control group (p < 0.001), overall survival was 72% and 31%, respectively (p < 0.001). Acute toxicity was mild and well tolerated.

DISCUSSION

Adjuvant radiotherapy to sites of bulky disease was the only difference to have an improvement in outcome in our patients; the use of rituximab during induction did not improve complete response rates and did affect overall survival; patients who received rituximab but not IFRT had a worse prognosis.

CONCLUSIONS

The use of IFRT in patients with primary mediastinal B-cell lymphoma who achieved complete response remain as the best treatment available, even in patients that received rituximab during induction.