The Role of Radiation Therapy in Patients With Relapsed or Refractory Hodgkin Lymphoma: Guidelines From the International Lymphoma Radiation Oncology Group

Successful treatment of paediatric refractory Hodgkin lymphoma with immunotherapy - A case report and literature review

AIM

To describe a rare case of primary refractory Hodgkin lymphoma nodular sclerosis syncytial variant in a child and review immunotherapy in relapsed/refractory Hodgkin lymphoma.

METHODS

We described the treatment course of a child with primary refractory classic Hodgkin lymphoma and discussed different options for salvage therapy, with an emphasis on immunotherapy. We searched PubMed for all published clinical trials investigating immunotherapy in classic Hodgkin lymphoma written in English until 31 June, 2023. The reference list of each identified paper was searched for additional publications.

RESULTS

Our patient was salvaged with anti-programmed cell death 1 (PD-1) antibody therapy followed by high-dose chemotherapy with autologous stem cell rescue. Radiotherapy was avoided. We identified five one-armed phase II trials investigating anti-PD-1 therapy in first relapse/refractory disease in a total of 254 patients aged 9-71 years, of which one included 31 children. The complete remission rate before high-dose chemotherapy was 59%-95% overall and 67%-89% among those with refractory disease.

CONCLUSION

Although it remains to be proven in randomised trials, anti-PD-1 therapy may provide higher complete response rates than traditional chemotherapy. Anti-PD-1 therapy has the potential to increase the chance of cure while decreasing the risk of late effects from chemotherapy and radiotherapy.

Contemporary radiation therapy use in Hodgkin lymphoma

Radiation therapy assumes a pivotal role in Hodgkin lymphoma management, especially within combined modality therapy. It serves as a cornerstone in early-stage disease and in mitigating high-risk instances of local relapse in advanced stages. Over recent decades, radiation therapy has undergone significant advancements, notably alongside diagnostic imaging improvements, facilitating the reduction of radiation field size and dosage. This progress has notably led to minimized toxicity while upholding treatment efficacy. This comprehensive review extensively evaluates the indications and advancements in radiation therapy for Hodgkin lymphoma, with a primary focus on enhancing treatment efficacy while minimizing radiation-related toxicities. The exploration encompasses a detailed examination of various radiation fields, techniques and delivery modalities employed in Hodgkin lymphoma treatment, including intensity-modulated radiation therapy (IMRT), volumetric modulated arc therapy (VMAT), and proton therapy. It delves into the intricacies of optimal dose selection and treatment planning strategies aimed at achieving maximal disease control while concurrently minimizing the risk of long-term side effects.

Future perspectives of radiation therapy for Hodgkin Lymphoma: Risk-adapted, response-adapted, and safer than before

Classical Hodgkin lymphoma is a lymphoproliferative disease with a good prognosis mainly seen in young people. Nevertheless secondary malignancy, cardiac disease and infertility may affect the long survivors with significant impact on quality of life, morbidity and overall survival. In the last decades several treatment strategies were evaluated to reduce the toxicity of first line treatment such as avoiding radiotherapy or its reduction in terms of dosage and extension. Many trials including interim Positron Emission Tomography evaluation fail to compare efficacy between combined modality treatment versus chemotherapy alone in particular in early stage disease. In this review we analyze which subset of patients could take advantage from proton therapy in terms of toxicity and cost effectiveness.

Patterns of progression after immune checkpoint inhibitors for Hodgkin lymphoma: implications for radiation therapy

ABSTRACT

Immune checkpoint inhibitors (ICIs) have demonstrated remarkable response rates in relapsed or refractory Hodgkin lymphoma (HL). Still, most patients eventually progress. Patterns of progression after ICIs are not well described and are essential to defining the role of local therapies in combination with ICIs. We identified patients who received ICIs for HL between 2013 and 2022. Fludeoxyglucose-18 positron emission tomography (FDG-PET) before initiating ICI and at progression on/after ICI were reviewed, and areas of active HL were recorded. An exploratory analysis of treatable progression included patients with ≤5 sites of disease on pre-ICI FDG-PET and progression only at pre-ICI sites. Ninety patients were identified; 69 had complete records, and of these, 32 (52%) had relapsed at ICI initiation, 17 (25%) were refractory, and 16 (23%) received ICI as first-line therapy. Forty-five of 69 patients had ≤5 sites of disease (limited) on pre-ICI FDG-PET. Patients with >5 sites of disease had a higher risk of progression, and every site of disease >5 sites conferred an additional 1.2x higher chance of progression. At a median follow-up of 4.0 years, 41 of 69 patients had progressed on/after ICIs (cumulative incidence 66.4%), and of these, 22 of 41 patients progressed only at pre-ICI sites (cumulative incidence 39.4%). In an exploratory analysis, the cumulative incidence of a treatable progression among 45 patients with limited disease was 34%. The cumulative incidence of any progression among this cohort was 58.9%. More than one-third of patients with limited disease before ICIs experienced progression only at pre-ICI sites of disease. These patients could be candidates for radiation during or after ICIs.

Involved-site Radiotherapy Delineation Dilemmas in the Treatment of Adult Hodgkin Lymphoma: Turkish Society for Radiation Oncology Hematological Oncology, Pediatric Oncology and TBI Study Group Case-based Questionnaire Review (TROD 03-005)

AIMS

The International Lymphoma Radiation Oncology Group (ILROG) defined involved-site radiotherapy (ISRT) guidelines. These rules offer a certain variability that allows for autonomous decision-making in diverse clinical settings. However, this flexibility also gives rise to conflicts about the selection of treatment fields in the daily decision-making process. The aim of this study was to show the extent of interobserver variability when ILROG-ISRT recommendations were used in different clinical scenarios.

MATERIALS AND METHODS

The 10-question survey used in our study consisted of two parts (part A and part B) and was prepared by four senior radiation oncologists experienced in the haemato-oncology field. The results were presented by stratifying according to clinical experience (<10 years, ≥10 years). Binomial tests (one-sided) were conducted to assess whether answers for each group and the whole group reached a consensus.

RESULTS

Twenty-six radiation oncologists, 13 of whom had less than 10 years of experience and 13 seniors, participated in the survey. Eighty per cent of respondents thought ILROG did not bring sufficient solutions for all clinical scenarios but offered solutions in some cases. In different case-based scenarios, the consensus among the respondents decreased down to 38%. Senior radiation oncologists were found to have more doubts about the adequacy of current guidelines.

CONCLUSIONS

ILROG guidelines allow for a high degree of variability in real-life clinical scenarios and different interpretation of the recommendations may lead to increased toxicity and recurrences. Therefore, there is a need for refinement in ISRT delineation strategies. On behalf of the Turkish Society for Radiation Oncology Hematological Oncology, Pediatric Oncology and TBI Study Group, we are planning to carry out further educational contouring sessions to detect the interobserver variability in real-life contouring cases.

The optimal management of relapsed and refractory Hodgkin lymphoma: post-brentuximab and checkpoint inhibitor failure

The treatment landscape of classical Hodgkin lymphoma has changed dramatically over the past decade. Relapsed and refractory mainstay therapeutics such as brentuximab vedotin (BV) and checkpoint inhibitors (CPIs) are being moved to earlier lines of therapy. However, the treatment of patients who progress after BV and CPI remains a challenge. Allogeneic stem cell transplantation still plays an important role in this patient population as the only current treatment approach with curative potential. Unfortunately, not all patients are transplant candidates, and many will still relapse afterward. Cytotoxic chemotherapy and radiation may be used for symptom palliation or as a bridge to transplant. Targeted therapies, including the antibody drug conjugate, camidanlumab tesirine, and transcriptional agents such mammalian target of rapamycin and histone deacetylase inhibitors have shown some potential in patients with refractory disease. In addition, combination therapies with CPIs and novel agents may help overcome resistance to therapy. Clinical trials with cellular therapies, including chimeric antigen receptor T cells targeting CD30 and allogeneic natural killer cells combined with AFM13, a CD30/CD16a-bispecific antibody, have shown promising results. The availability of more therapeutic options for this patient population is eagerly awaited.

Optimizing Treatment for Relapsed/Refractory Classic Hodgkin Lymphoma in the Era of Immunotherapy

Most patients with classic Hodgkin lymphoma (cHL) are cured with combination chemotherapy, but approximately 10-20% will relapse, and another 5-10% will have primary refractory disease. The treatment landscape of relapsed/refractory (R/R) cHL has evolved significantly over the past decade following the approval of brentuximab vedotin (BV), an anti-CD30 antibody-drug conjugate, and the PD-1 inhibitors nivolumab and pembrolizumab. These agents have significantly expanded options for salvage therapy prior to autologous hematopoietic cell transplantation (AHCT), post-transplant maintenance, and treatment of relapse after AHCT, which have led to improved survival in the modern era. In this review, we highlight our approach to the management of R/R cHL in 2023 with a focus on choosing first salvage therapy, post-transplant maintenance, and treatment of relapse after AHCT. We also discuss the management of older adults and transplant-ineligible patients, who require a separate approach. Finally, we review novel immunotherapy approaches in clinical trials, including combinations of PD-1 inhibitors with other immune-activating agents as well as novel antibody-drug conjugates, bispecific antibodies, and cellular immunotherapies. Ongoing studies assessing biomarkers of response to immunotherapy and dynamic biomarkers such as circulating tumor DNA may further inform treatment decisions and enable a more personalized approach in the future.

Sequencing novel agents in the treatment of classical Hodgkin lymphoma

INTRODUCTION

Classical Hodgkin lymphoma (cHL) is a curable disease, with durable remission achieved in about 80% of patients following first-line treatment. Three new drugs were introduced to the daily use in cHL: brentuximab vedotin (BV), nivolumab, and pembrolizumab. All three drugs were initially approved for the treatment of relapsed/refractory cHL (RRHL) and with their promising outcomes, they are now incorporated in different stages of the treatment.

AREAS COVERED

We performed a literature search using PubMed on all cHL studies investigating BV and CPIs within the past 10 years. We analyzed literature to presume the sequencing of these novel agents.

EXPERT OPINION

Addition of BV or nivolumab to AVD backbone in the frontline setting showed promising activity in advanced stage cHL. BV and CPIs combined with chemotherapy in the second-line treatment of cHL are evaluated in phase 2 studies and comparable results are reported. The results of BrECADD, with good efficacy and toxicity profile, should be followed. Pembrolizumab was shown to be more effective in RRHL compared to BV in patients who have relapsed post-ASCT or ineligible for ASCT. BV is used in post-ASCT maintenance in high-risk cases, although its role will be questioned as it is increasingly used in the frontline treatment.

Modern PET-Guided Radiotherapy Planning and Treatment for Malignant Lymphoma

Malignant lymphoma comprises a broad spectrum of diverse entities originating from different types of lymphocytes. In the last century, successive improvements of treatment possibilities have led to an continuous amelioration of patient prognosis from lethal outcome to high rates of disease control and long-term survivors. PET/CT-based imaging plays a key role in stratification of stage and treatment response. Especially for radiotherapy, an essential treatment modality for lymphoma patients, functional imaging and the reevaluation of disease activity after frontline chemotherapy has led to major improvements regarding size of treatment fields and toxicity. International expert groups like the International Lymphoma Radiation Oncology Group (ILROG) develop guidelines for the optimal use of imaging for treatment planning. The shift from uniform large-field treatment volumes to complex individual setups taking into account biological response-assessments based on functional imaging resulted in a further de-escalation of side effects and modernization of lymphoma treatment. This paper aims to summarize the use of FDG-PET-imaging for radiation therapy planning in malignant lymphoma in the context of historic and future developments, as well as associated limitations and challenges ahead. We will discuss the contemporary standard of care as recommended by international expert guidelines like the ILROG, the national comprehensive cancer network (NCCN), as well as the newly updated German S3-guidelines.

Single or tandem autologous stem cell transplantation for treating Chinese patients with refractory/relapsed classical Hodgkin lymphoma

BACKGROUND

Autologous stem cell transplantation (ASCT) is the standard treatment strategy for refractory or relapsed classical Hodgkin lymphoma (R/R cHL). However, a single transplantation is insufficient to cure the disease because of unfavorable risk factors. Herein, we evaluated the outcomes of single or tandem ASCT in patients with R/R cHL, especially in high-risk patients.

METHODS

We retrospectively analyzed R/R cHL patients who underwent single or tandem ASCT between April 2000 and June 2021 at the Beijing Cancer Hospital and Peking University International Hospital.

RESULTS

A total of 134 patients were enrolled. Patients were allocated to a favorable-risk group (group A, n = 33), an unfavorable-risk group (group B, n = 81) that underwent single ASCT, and an unfavorable-risk group that underwent tandem ASCT (group C, n = 20). The median follow-up time was 99 months (range, 91-107 months), and no treatment-related deaths occurred after single or tandem ASCT. However, 27 patients (2 in group C) died during the follow-up period. The groups A, B, and C had 5-year progression-free survival (PFS) rates of 77.05%, 45%, and 74.67%, respectively (p = 0.0014), and 5-year overall survival (OS) rates of 89.85%, 76.06%, and 95%, respectively (p = 0.18). Neither the median PFS rates of groups A and C nor the OS rates of all groups were reached.

CONCLUSIONS

Our study discusses the advantages of tandem transplantation for high-risk patients with R/R cHL.

Efficacy and toxicity of infradiaphragmal radiotherapy fields in lymphoma patients: a single-centre experience

PURPOSE

Data on efficacy and toxicity of infradiaphragmal radiotherapy fields in lymphoma patients are scarce. We therefore performed this retrospective study to analyse our experience with radiotherapy exclusively to infradiaphragmal fields.

MATERIALS AND METHODS

we retrospectively evaluated 101 patients treated between 2003 and 2014. Median dose was 36 Gy, range 4 to 54 Gy. Medium dose per fraction was 2 Gy, range 1.5 to 7 Gy.

RESULTS

After a median follow-up of 66 months (range 1-211 months), we observed lymphoma recurrence in 38 patients (38%), five in the RT field and 33 out-of-field. Recurrences were significantly more frequent in the salvage group (17 out-of-field and 4 in-field in 31 patients) than in adjuvant group (16 out-of-field and 1 in-field in 70 patients; p < 0.001). The 2-, 5- and 10-year event-free survival (EFS) rates were 62%, 56% and 54%. The 2-, 5- and 10-year overall survival (OS) rates for the entire group of patients are 73%, 60% and 54%, respectively. Acute side effects occurred in 43 (43%) patients, most frequent gastrointestinal in 26 (26%) patients. Late side effects occurred in 12 (12%) of all patients, 6 of 23 (26%) followed up for more than 10 years. Six patients developed secondary cancers, four gastrointestinal disturbances, two diabetes mellitus and three renal failure.

CONCLUSION

Radiotherapy is an effective and safe treatment option for patients with infradiaphragmatic lymphoma providing excellent local disease control with minimal late toxicity. Infradiaphragmatic lymphoma localization should not be regarded as a contraindication for use of radiotherapy. However, patients should be monitored for a secondary malignancy.

Peritransplant Radiation Therapy in Patients With Refractory or Relapsed Hodgkin Lymphoma Undergoing Autologous Stem Cell Transplant: Long-Term Results of a Retrospective Study of the Fondazione Italiana Linfomi

PURPOSE

In this multicenter collaboration, we report real-world data in the largest published series of long-term outcomes for patients with relapsed/refractory (r/r) Hodgkin lymphoma (HL) treated with peritransplant radiation therapy (pt-RT) and high-dose chemotherapy with autologous stem cell transplant (ASCT).

METHODS AND MATERIALS

We conducted a retrospective analysis including data from 12 institutions. Eligibility required histologic diagnosis of HL, receipt of ASCT plus pt-RT between 2004 and 2014 for r/r HL, and age ≥18 years at the time of ASCT. All patients received salvage chemotherapy for maximum debulking before ASCT. Metabolic responses were scored according to the Lugano Classification. The primary endpoint was overall survival (OS). Univariate and multivariate Cox proportional hazards were calculated to estimate the effect of covariates on patients' outcome.

RESULTS

One hundred thirty-one patients were eligible: 68 were male (52%), and median age at ASCT was 32 years (range, 18-70). At the time of diagnosis with r/r HL, 92 patients (70%) had limited (stage I-II) disease, and 10 patients (8%) had bulky disease. Pt-RT was given pre-ASCT in 32 patients (24%) and post-ASCT in 99 (76%); median prescribed dose was 30.6 Gy (range, 20-44 Gy). With median follow-up of 60 months, 3- and 5-year OS were 84% and 77%, while 3- and 5-year progression-free survival were 75% and 72%, respectively. On univariate and multivariate analysis, advanced stage at relapse (hazard ratio [HR], 2.18; P = .04), irradiation of >3 sites (HR, 3.69; P = .01), and incomplete metabolic response after salvage chemotherapy (HR, 2.24; P = .01) had a negative effect on OS. The sequencing of pt-RT (pre- vs post-ASCT) did not affect outcomes.

CONCLUSIONS

Overall, the addition of pt-RT to ASCT for patients with r/r HL is associated with very good outcomes. Limited relapsed disease with ≤3 sites involved and achievement of complete metabolic response after salvage chemotherapy were predictive of more favorable prognosis.

The role of transplantation in Hodgkin lymphoma

Despite the success of frontline anthracycline-based chemotherapy for classical Hodgkin Lymphoma (cHL), approximately 15% of patients do not achieve an adequate response and require further therapy. For transplant-eligible patients, additional treatment followed by high-dose chemotherapy and autologous hematopoietic stem cell transplantation (autoHCT) provides a durable response in 50% of patients. The most refractory patients, including those requiring multiple lines of therapy to achieve a response or those relapsing after an autoHCT, may achieve long-term survival with allogeneic hematopoietic stem cell transplant (alloHCT). Contemporary salvage regimens used as a bridge to transplant have expanded to include not only non-cross resistant chemotherapy, but also brentuximab vedotin (BV) and checkpoint inhibitors (CPI). As the management of relapsed/refractory (R/R) cHL evolves with the introduction of novel agents, so too does the role of transplantation. The paradigm of chemosensitivity as a predictor for autoHCT efficacy is being challenged by favorable post- autoHCT outcomes in heavily pre-treated CPI-exposed patients. Contemporary supportive care measures, validated comorbidity assessments, and an increased donor pool with haploidentical donors have broadened the application of transplantation to an increasingly older and diverse patient population. Despite the introduction of increasingly effective treatment options for R/R cHL, transplantation continues to play an important role in the management of these patients. In this review, we explore the impact of salvage therapy on autoHCT, conditioning regimens, maintenance therapy and the diminishing role of alloHCT for patients with cHL.

Novel Salvage Therapy Options for Initial Treatment of Relapsed/Refractory Classical Hodgkin's Lymphoma: So Many Options, How to Choose?

The treatment landscape for relapsed/refractory classical Hodgkin's lymphoma (cHL) has evolved with the introduction of several novel agents. Historically, the standard of care for relapsed cHL was salvage chemotherapy followed by autologous stem cell transplant (ASCT). However, many patients are ineligible for ASCT or will have poor responses to salvage chemotherapy and ASCT. Brentuximab vedotin (BV) and checkpoint inhibitors (nivolumab/pembrolizumab) were initially approved in the post-ASCT setting. However, as a result of excellent responses and durable outcomes in this setting, they are now being studied and explored in earlier lines of therapy. Additionally, these agents are also being studied for post-transplant consolidation and maintenance with promising results in improving progression-free survival. We will review current salvage therapy options involving these novel agents and provide comparisons between regimens to aid the clinician in selecting the appropriate salvage regimen for patients who progress after first-line therapy.

Current salvage therapies in Hodgkin lymphoma

Hodgkin lymphoma is a B-cell malignancy with approximately 85-95% complete remission rate following frontline therapy; however, relapsed/refractory disease occurs in roughly 10-30% of patients after treatment. Salvage therapy conventionally relies upon cytotoxic chemotherapy followed by high-dose chemotherapy and autologous stem cell transplantation. A considerable number of patients experience relapse after transplantation, and further salvage management has included the use of allogeneic transplantation and radiotherapy. In the past decade, novel therapies including, brentuximab vedotin, PD-1 inhibitors, and the incorporation of PET-imaging into management have changed the paradigm of relapsed/refractory disease care. Novel therapies have been investigated in both single and combination regimens with other novel therapies and traditional chemotherapies. There is promising early work into the utility of CD30.CAR-T cell therapy, AFM13, camidanlumab tesirine, novel PD-1 inhibitors, and JAK1/JAK2 inhibition in management. Herein, we will review current salvage therapies in Hodgkin lymphoma and future directions in relapsed/refractory disease management.

Outcomes of adults with lymphoma treated with nonmyeloablative TLI-ATG and radiation boost to high risk or residual disease before allogeneic hematopoietic cell transplant

We evaluated the impact on survival of antithymocyte globulin conditioning (TLI-ATG) with radiation (RT) boost to high risk or residual disease before allogeneic hematopoietic cell transplant (allo-HCT) for adults with lymphoma (excluding mycosis fungoides and low-grade NHL other than SLL/CLL). Of 251 evaluable patients, 36 received an RT boost within 3 months of allo-HCT at our institution from 2001 to 2016. At the time of TLI-ATG, patients who received boost vs no boost had a lower rate of CR (11% vs 47%, p = 0.0003), higher rates of bulky disease (22% vs 4%, p < 0.0001), extranodal disease (39% vs 5%, p < 0.0001), and positive PET (75% vs 28%, p < 0.00001). In the boost group, the median (range) largest axial lesion diameter was 5.2 cm (1.8-22.3). Median follow-up was 50.2 months (range: 1-196). There was no significant difference in OS, time to recurrence, or time to graft failure with vs without boost. A trend toward higher percent donor CD3⁺ chimerism was seen with vs without boost (p = 0.0819). The worst boost-related toxicity was grade 2 dermatitis. RT boost may help successfully mitigate the risk of high risk or clinically evident residual disease in adults with lymphoma undergoing allo-HCT.

Radiotherapy of lymphomas

Radiotherapy for Hodgkin lymphomas has evolved a lot over time, but still plays an important role, almost always in addition to chemotherapy, for the management of the early stages. The major objective is to preserve the quality of life of patients who will be cured from this disease in the vast majority of cases. Also, the personalization of the indications for the purpose of de-escalating toxicity is very refined and is essentially based on the pre- and pertherapeutic assessment by FDG-PET. The indications for radiotherapy are more limited for non-Hodgkin lymphomas, but the same principles are found, regardless of the histological type. We present the update of the recommendations of the French society of oncological radiotherapy for radiotherapy of lymphomas, which remains a very evolving field in terms of therapeutic strategy and evaluation.

How to choose first salvage therapy in Hodgkin lymphoma: traditional chemotherapy vs novel agents

Approximately 10% to 30% of patients with classical Hodgkin lymphoma (cHL) develop relapsed or refractory (R/R) disease. Of those patients, 50% to 60% show long-term progression-free survival after standard salvage chemotherapy followed by high-dose chemotherapy (HDCT) and autologous stem cell transplant (ASCT). In the past decade, novel therapies have been developed, such as the CD30-directed antibody-drug conjugate brentuximab vedotin and immune checkpoint inhibitors, which have greatly extended the treatment possibilities for patients with R/R cHL. Several phase 1/2 clinical trials have shown promising results of these new drugs as monotherapy or in combination with chemotherapy, but unfortunately, very few randomized phase 3 trials have been performed in this setting, making it difficult to give evidence-based recommendations for optimal treatment sequencing. Two important goals for the improvement in the treatment of R/R cHL can be identified: (1) increasing long-term progression-free and overall survival by optimizing risk-adapted treatment and (2) decreasing toxicity in patients with a low risk of relapse of disease by evaluating the need for HDCT/ASCT in these patients. In this review, we discuss treatment options for patients with R/R cHL in different settings: patients with a first relapse, primary refractory disease, and in patients who are ineligible or unfit for ASCT. Results of clinical trials investigating novel therapies or strategies published over the past 5 years are summarized.

'Le Roi est mort, vive le Roi': New Roles of Radiotherapy in the Treatment of Lymphomas in Combination With Immunotherapy

BACKGROUND

immunotherapy (IT), including checkpoint inhibitors (CIs) and Chimeric Antigen Receptor T cell therapy (CAR-T) revolutionized the treatment of relapsing or refractory (r/r) lymphoma. Several preliminary experiences evaluated concomitant administration of radiotherapy and IT.

METHODS

we performed a systematic review of current literature as of March 30, 2020. A total of 1090 records was retrieved, 42 articles were selected on the basis of title and abstract and, after the removal of analyses with no original data or insufficient clinical information, 28 papers were included in the review.

RESULTS

previous studies were mostly represented by case reports/series or small cohorts. Nonetheless, combination of radiotherapy and CIs or CAR-T led to promising outcomes, resulting in extremely high rates of complete response and improving progression free and overall survival compared with data from recent clinical trials. Combination of RT and CIs had a fair toxicity profile with no reports of severe side effects. Within the limits of the small cohorts retrieved, RT seems a superior option compared with systemic treatment as a 'bridge' to CAR-T and could as well reduce severe complications rates. Radiotherapy could elicit immune response against lymphoma, as demonstrated by multiple cases of abscopal effect and its inclusion in anti-neoplastic vaccines protocols.

CONCLUSION

The results of this review warrant the evaluation of combination of RT and immunotherapy in larger and preferably prospective and randomized cohorts to confirm these preliminary impressive outcomes. The optimal dose, fractionation and timing of RT still have to be clarified.

Total tumor burden in lymphoma - an evolving strong prognostic parameter

Total metabolic tumor volume (TMTV), a new parameter extracted from baseline FDG-PET/CT, has been recently proposed by several groups as a prognosticator in lymphomas before first-line treatment. TMTV, the sum of the metabolic volume of each lesion, is an index of the metabolically most active part of the tumor and highly correlates with the total tumor burden. TMTV measurement is obtained from PET images processed with different software and techniques, many being now freely available. In the various lymphoma subtypes where it has been measured, such as diffuse large B-cell lymphoma, Hodgkin lymphoma, Follicular Lymphoma, and Peripheral T-cell lymphoma, TMTV has been reported as a strong predictor of outcome (progression-free survival and overall survival) often outperforming the clinical scores, molecular predictors, and results of interim PET. Combined with these scores, TMTV improves the stratification of the populations into risk groups with different outcomes. TMTV cut-off separating the high-risk from the low-risk population impacts the outcome whatever the technique used for its measurement and an international harmonization is ongoing. TMTV is a unique and easy tool that could replace the surrogate of tumor burden included in the prognostic indexes used in lymphoma and help tailor therapy. Other parameters extracted from the baseline PET may give an information on the dissemination of this total tumor volume such as the maximum distance between the lesions. Trials based on TMTV would probably demonstrate its predictive value.

Immune checkpoint inhibitors in combination with radiotherapy as salvage treatment for relapsed/refractory classical Hodgkin lymphoma: A retrospective analysis in 12 patients

The rate of complete remission (CR) with the anti-PD1 immune checkpoint inhibitors (ICI) nivolumab (N) and pembrolizumab (P) in patients with relapsed/refractory (R/R) classical Hodgkin lymphoma (cHL) is low (20-30%), and the majority of patients eventually relapse. One strategy to improve their outcome is to combine ICI with radiotherapy (ICI-RT), taking advantage of a supposed synergistic effect. We retrospectively collected data of 12 adult patients with R/R cHL treated with ICI-RT delivered during or within 8 weeks from the start or after the end of ICI. Median age at ICI-RT was 37 years, 50% had previously received an autologous stem cell transplantation (SCT) and 92% brentuximab vedotin. RT was given concurrently, before or after ICI in 4, 1 and 7 patients. Median RT dose was 30Gy, for a median duration of 22 days. Median number of ICI administrations was 15. Overall response and CR rate were 100% and 58%. Nine patients received subsequent SCT consolidation (7 allogeneic and 2 autologous). After a median follow-up of 18 months, 92% of patients were in CR. No major concerns about safety were reported. ICI-RT combination appears to be a feasible and highly active bridge treatment to transplant consolidation.

Residual Site Radiotherapy After Immunochemotherapy in Primary Mediastinal B-Cell Lymphoma: A Monoinstitutional Retrospective Study

AIM

To evaluate the efficacy of residual site radiation therapy (RSRT) on local control (LC), progression-free (PFS) and overall (OS) survival in patients with primary mediastinal lymphoma (PMBCL), following rituximab and chemotherapy treatment (ICHT).

PATIENTS AND METHODS

The study included 34 patients with PMBCL treated between 2006 and 2014 with ICHT with/without autologous stem cell transplantation and RSRT. Between the end of ICHT/stem cell transplantation and RSRT, patients were evaluated with ¹⁸F-fluorodeoxyglucose positron-emission tomography. The gross tumor volume included morphological mediastinal residual disease after ICHT/SCT. The percentage of LC, PFS and OS were assessed.

RESULTS

All patients received RSRT with a median dose of 30 Gy. Median follow-up was 82 months. One patient out of 34 (3%) showed progressive disease 9 months from diagnosis. The 10-year PFS and OS were 97% and 97% respectively.

CONCLUSION

RSRT in patients with PMBCL treated with ICHT did not impact unfavorably on LC and patient survival.

Favorable Outcome After Adjuvant Involved-Field Radiotherapy After Autologous Hematopoietic Stem-Cell Transplantation in Patients With High-Risk Relapsed/Refractory Lymphoma: A Single-Center Experience

BACKGROUND

Patients with refractory or relapsed lymphoma diagnosed with bulky disease at relapse or with residual disease after salvage treatment are considered to have a dismal outcome, even after autologous hematopoietic stem-cell transplantation, as a result of disease recurrence. To minimize the risk of relapse after receipt of a transplant, involved-field radiotherapy (IFRT) to sites of either bulky or localized residual disease has been utilized; however, the ideal timing for irradiation remains controversial. The aim of this study was to assess the safety and efficacy of IFRT in the early period after transplantation.

PATIENTS AND METHODS

We retrospectively evaluated the outcome of 24 autografted patients with relapsed/refractory lymphoma who presented with bulky disease at relapse or who had a persistent localized residual mass after salvage treatment and consolidated with IFRT within 4 months after autografting.

RESULTS

No significant toxicity was noticed during the early postradiotherapy period, while graft function was not impaired. After a median follow-up of 3 years for survivors, 21 patients were alive, 19 of whom were event free, while 2 patients died of disease recurrence and 1 died of treatment-related myelodysplastic syndrome. The 3-year overall, lymphoma relapse-free, and event-free survival rates were 86%, 86%, and 82%, respectively.

CONCLUSION

Taking into consideration the poor-risk features of the study cohort, IFRT provided early after autologous hematopoietic stem-cell transplantation showed a safe and well-tolerated toxicity profile and demonstrated long-term effective tumor control, as reflected in the promising survival rates.

Relapsed, Refractory, or Advanced Hodgkin Lymphoma: A Single-Center Experience

PURPOSE

To assess the treatment and outcomes of patients with relapsed, refractory, or advanced Hodgkin lymphoma treated with consolidation or salvage radiotherapy.

PATIENTS AND METHODS

We studied all patients diagnosed with this profile treated by radiotherapy in our center between 2006 and 2019.

RESULTS

A total of 33 patients who received external-beam radiotherapy for advanced (21%), relapsed (52%), or refractory (24%) Hodgkin lymphoma were studied. Median [interquartile range] age was 25 [22-38] years, with 11 women (33%). The follow-up after first-line treatment was 28 [10-53] months. Number of chemotherapy lines received before radiotherapy was 3 [1-4]. Fourteen patients (42%) had undergone autologous stem-cell transplantation before radiotherapy, and 2 patients were treated by radiotherapy alone. Nine patients (27%) were treated by involved-field radiotherapy, 17 (52%) by involved-site radiotherapy, 5 (17%) by involved-node radiotherapy, and 2 by other volumes. The acute toxicity profile was favorable, with grade 1 radiodermatitis (33%) or dysphagia (30%). Overall, 21 patients (64%) experienced prolonged complete response and 12 experienced relapse (36%) after radiotherapy. Median disease-free survival was 68.8 months.

CONCLUSIONS

External-beam radiotherapy should be considered an effective treatment modality for advanced, relapsed, or refractory Hodgkin lymphoma as part of a multimodal approach.

Hodgkin lymphoma

Hodgkin lymphoma (HL) is a B cell lymphoma characterized by few malignant cells and numerous immune effector cells in the tumour microenvironment. The incidence of HL is highest in adolescents and young adults, although HL can affect elderly individuals. Diagnosis is based on histological and immunohistochemical analyses of tissue from a lymph node biopsy; the tissue morphology and antigen expression profile enable classification into one of the four types of classic HL (nodular sclerosis, mixed cellularity, lymphocyte-depleted or lymphocyte-rich HL), which account for the majority of cases, or nodular lymphocyte-predominant HL. Although uncommon, HL remains a crucial test case for progress in cancer treatment. HL was among the first systemic neoplasms shown to be curable with radiation therapy and multiagent chemotherapy. The goal of multimodality therapy is to minimize lifelong residual treatment-associated toxicity while maintaining high levels of effectiveness. Recurrent or refractory disease can be effectively treated or cured with high-dose chemotherapy followed by autologous haematopoietic stem cell transplantation, and prospective trials have demonstrated the potency of immunotherapeutic approaches with antibody-drug conjugates and immune checkpoint inhibitors. This Primer explores the wealth of information that has been assembled to understand HL; these updated observations verify that HL investigation and treatment remain at the leading edge of oncological research.

Radiation Therapy for Advanced-Stage Hodgkin Lymphoma

The backbone of treatment for patients with advanced-stage Hodgkin lymphoma is systemic therapy. The use of radiation therapy as a component of combined-modality treatment in this setting is controversial. In this review, we describe the data in support of and against the use of radiation therapy for stage III and IV Hodgkin lymphoma. Specifically, we review the data for the use of radiation therapy in the consolidation and partial-response settings, including for patients with initial bulky disease. We also discuss the use of radiation therapy in the era of more modern systemic therapies, including checkpoint inhibitors and brentuximab vedotin.

Hodgkin Lymphoma, Version 2.2020, NCCN Clinical Practice Guidelines in Oncology

The NCCN Clinical Practice Guidelines in Oncology for Hodgkin Lymphoma (HL) provide recommendations for the management of adult patients with HL. The NCCN panel meets at least annually to review comments from reviewers within their institutions, examine relevant data, and reevaluate and update their recommendations. Current management of classic HL involves initial treatment with chemotherapy alone or combined modality therapy followed by restaging with PET/CT to assess treatment response. Overall, the introduction of less toxic and more effective regimens has significantly advanced HL cure rates. This portion of the NCCN Guidelines focuses on the management of classic HL.

ILROG emergency guidelines for radiation therapy of hematological malignancies during the COVID-19 pandemic

The International Lymphoma Radiation Oncology Group (ILROG) guidelines for using radiation therapy (RT) in hematological malignancies are widely used in many countries. The emergency situation created by the COVID-19 pandemic may result in limitations of treatment resources. Furthermore, in recognition of the need to also reduce the exposure of patients and staff to potential infection with COVID-19, the ILROG task force has made recommendations for alternative radiation treatment schemes. The emphasis is on maintaining clinical efficacy and safety by increasing the dose per fraction while reducing the number of daily treatments. The guidance is informed by adhering to acceptable radiobiological parameters and clinical tolerability. The options for delaying or omitting RT in some hematological categories are also discussed.

Treatment of Hodgkin Lymphoma Relapsed after Autologous Stem Cell Transplantation

Although autologous stem cell transplantation (auto-HCT) is the standard of care for patients with refractory/relapsed (R/R) classical Hodgkin’s lymphoma (cHL), there is still a significant proportion of patients that relapse after the procedure. This review contemplates different treatment strategies for patients with cHL that relapse or progress after auto-HCT. Allogeneic stem cell transplantation (allo-HCT) has, for many years, been the only curative option for this group of patients. Although the advent of haploidentical donors has allowed for the possibility to allograft almost all patients that are in need of it and to eventually improve historical results, allo-HCT is still associated with substantial morbidity and mortality. Brentuximab vedotin (BV) is an antibody drug conjugate that binds to CD30 antigen; BV is able to give up to 34% metabolic complete remissions (mCR) in HL patients that fail auto-HCT. Unleashing the immune system with PD-1 inhibitors has resulted in remarkable responses in a number of malignancies, including HL. Nivolumab and pembrolizumab offer a 20%–25% mCR and 40%–50% partial remissions, with an acceptable safety profile. R/R cHL do have several options nowadays that, without any doubt, have significantly improved the long-term outcome of this hard-to-treat population.

Risk and Response Adapted Treatment Guidelines for Managing First Relapsed and Refractory Classical Hodgkin Lymphoma in Children and Young People. Recommendations from the EuroNet Pediatric Hodgkin Lymphoma Group

The objective of this guideline is to aid clinicians in making individual salvage treatment plans for pediatric and adolescent patients with first relapse or refractory (R/R) classical Hodgkin lymphoma (cHL). While salvage with standard dose chemotherapy followed by high dose chemotherapy and autologous stem cell transplant is often considered the standard of care in adult practice, pediatric practice adopts a more individualized risk stratified and response adapted approach to salvage treatment with greater use of non-transplant salvage. Here, we present on behalf of the EuroNet Pediatric Hodgkin Lymphoma group, evidence and consensus-based guidelines for standardized diagnostic, prognostic and response procedures to allocate children and adolescents with R/R cHL to stratified salvage treatments.

Advances in Therapy for Relapsed or Refractory Hodgkin Lymphoma

PURPOSE OF REVIEW

The landscape of relapsed or refractory (R/R) Hodgkin lymphoma (HL) treatment has changed significantly since the FDA approval of brentuximab vedotin in 2011. In this review, we summarize the recent advances in the therapy for R/R classical Hodgkin lymphoma (cHL).

RECENT FINDINGS

Immunotherapies with pembrolizumab, nivolumab, and ipilimumab, and chimeric antigen receptor (CAR) T cell therapies have shown promising results in early phase trials. Other novel agents under investigation include targeted therapies with histone deacetylase inhibitors, Janus kinase 2 inhibitors, and immunomodulators. While further studies with larger populations and longer follow-up times are needed to determine the safe and effective combinations, these novel approaches represent a growing list of treatment options that are on the horizon to improve the cure rate and increase duration of remission for R/R HL patients.

Outcome predictors of autologous hematopoietic stem cell transplantation in children with relapsed and refractory Hodgkin lymphoma: Single-center experience in a lower-middle-income country

BACKGROUND

Children and adolescents with HL have excellent long-term survival exceeding 95% after combined modality treatment. However, about 20% will either relapse or have PRF. Salvage HDCT followed by AHSCT is considered to be the preferential treatment.

OBJECTIVE

To describe the outcome (OS and EFS) and prognostic factors in pediatric patients with relapsed or refractory HL (r/rHL) who underwent AHSCT.

METHODS

We retrospectively included 43 pediatric patients with r/rHL who underwent AHSCT from July 1, 2007, till December 31, 2016, at the Children's Cancer Hospital of Egypt. MAC regimen given was CMV.

RESULTS

Of the whole cohort, 88.4% of patients achieved CR, while 11.6% had a positive PET scan prior to transplantation. The 3-year OS and EFS were 85% and 70.6%, respectively. The 3-year OS for patients > 10 years was 94% versus 65.5% for patients 10 years of age or younger (P = 0.046). There is strong tendency toward better 3-year OS for patients with negative PET scan as compared to those with positive PET scan before AHSCT, 89.4% vs 60%, respectively (P = 0.059). This tendency is also applicable when looking at the 3-year EFS for the two groups, 78.3% vs 40%, respectively (P = 0.069).

CONCLUSION

Poor predictors of OS were younger age and positive PET scan before AHSCT. The latter, along with single modality treatment before AHSCT, were poor predictors of EFS.

Radiotherapy in combination with nivolumab for relapsed/refractory classical Hodgkin lymphoma: About two cases

Hodgkin lymphoma is a highly curable malignancy involving lymph nodes and the lymphatic system. Even at late stage disease, about 70% of patients will be cured with standard first line therapy. For patients who experience relapse or refractory classical Hodgkin lymphoma, the standard treatment option is high-dose chemotherapy followed by autologous stem cell rescue or transplant. However about 50% of patients will have recurrence after high-dose chemotherapy followed by autologous stem cell rescue or transplantation and have worse prognosis with median overall survival of 32% at 5 years. The anti-PD1 checkpoints inhibitors pembrolizumab and nivolumab have remarkably improved outcomes of patients with relapse of refractory classical Hodgkin lymphoma after high-dose chemotherapy followed by autologous stem cell rescue or transplantation. On the other hand, radiotherapy is an entire component of salvage therapy and its efficacy is now well established in term of local disease control in sites of relapsed or refractory Hodkin lymphoma. Defining the optimal modality and timing of radiotherapy as these new agents arrive is a challenge. An interesting approach is the combination of radiotherapy with checkpoint inhibitor and the possibility of stopping the treatment when complete response is achieved. We add to the literature two new cases of combination of radiotherapy with immunotherapy in patients who relapsed after high-dose chemotherapy followed by autologous stem cell rescue or transplantation and consolidation with brentuximab vedotin, resulting in excellent outcomes.

Relapsed and Refractory Classical Hodgkin Lymphoma: Keeping Pace With Novel Agents and New Options for Salvage Therapy

The management of relapsed and refractory classic Hodgkin lymphoma (HL) has changed substantially since the approval of brentuximab vedotin (BV) and the checkpoint inhibitors nivolumab and pembrolizumab. For patients progressing after frontline treatment, second-line therapy followed by consolidation with autologous stem cell transplant (ASCT) remains the standard of care; however, although traditional combination chemotherapy regimens previously represented the only options for salvage, BV is now routinely incorporated into second-line therapy, and studies are evaluating checkpoint inhibitors in this setting as well. After ASCT, BV maintenance improves progression-free survival for patients at higher-risk, and studies are evaluating the role of post-ASCT maintenance with checkpoint inhibitors. Management of HL that progresses after ASCT remains a challenge. Although many patients achieve prolonged disease control with checkpoint inhibitors, the majority eventually progress and require additional therapy. Newer approaches, including CD30-directed chimeric antigen receptor-T-cell therapy, appear promising. Furthermore, allogeneic stem cell transplant remains an important consideration. Altogether, BV and checkpoint inhibitors have improved survival for patients with relapsed and refractory HL. However, the ideal place for these drugs in the treatment course of HL is still under investigation. Ongoing studies testing novel combinations and assessing for prognostic and predictive markers will ultimately define the optimal setting for these drugs in the treatment of relapsed and refractory HL.

Patterns of Relapse After Salvage Autologous Stem Cell Transplant for Hodgkin's Lymphoma: Should Sites of Relapse Relative to Initially Involved Sites Be Used to Guide Indications for Peri-Transplant Radiation Therapy

PURPOSE

We aimed to assess patterns of relapse in patients undergoing salvage autologous stem cell transplant (ASCT) for relapsed Hodgkin lymphoma in the modern era with the hypothesis that patients who suffer a relapse at initially involved sites are at increased risks of relapse post-ASCT that may help guide the application of peri-transplant radiation therapy.

METHODS AND MATERIALS

A retrospective review was conducted of 38 patients undergoing ASCT between 2002 and 2017 for relapsed or refractory Hodgkin lymphoma. The site of relapse at the time of ASCT and subsequent relapses were compared with sites of the initial involvement at the time of diagnosis using follow-up imaging (most commonly positron emission computed tomography). Relapse and overall survival rates were calculated from the date of ASCT using the Kaplan-Meier method with a multivariate analysis, completed using a Cox multivariate analysis.

RESULTS

The median follow-up time was 38 months (interquartile range, 18-66 months). Twenty-two patients (58%) suffered a relapse after ASCT at a median time to relapse of 9.1 months (interquartile range, 2.9-12.3 months) with a 5-year risk of relapse of 58% (95% confidence interval [CI], 41%-75%). On univariate analysis, relapse at an initially involved site was significant for higher rates of relapse at 71% at 5-years (95% CI, 52%-90%) compared with relapse at initially uninvolved sites at 30% (95% CI, 2%-58%; P = .05). The relapse rate was also significantly higher in patients age <30 years at the time of diagnosis at 80% (95% CI, 59%-100%) compared with 40% (95% CI, 18%-62%) at 5 years in patients aged >30 years (P < .01). On multivariate analysis, relapse at initially involved sites was significant for higher rates of relapse (hazard ratio: 8.3; 95% CI, 1.2-57.4; P = .03).

CONCLUSIONS

Relapses at initially involved sites may potentially increase the risk of relapse after ASCT. Additional studies are needed to clarify whether this should be used as an additional factor to guide recommendations for peri-transplant radiation therapy.

Controversies in the Treatment of Classical Hodgkin Lymphoma

Hodgkin lymphoma (HL) is a B-cell-derived malignancy that mostly affects young adults. Pathologically, HL is divided into classical HL (cHL) and the rare entity of nodular lymphocyte-predominant HL. Classical HL is characterized by few malignant cells termed Hodgkin and Reed–Sternberg cells embedded in an inflammatory background. The treatment of cHL has consistently improved over the last decades so that current standard approaches result in long-term remission rates in excess of 80%. However, potentially lethal therapy-related late complications affect an increasing number of survivors. For this reason, issues regarding the optimal treatment of cHL patients are still fiercely debated. Questions under discussion include how treatment can be guided by interim positron emission tomography, the best initial treatment for advanced-stage disease and the use of targeted drugs such as the antibody–drug conjugate brentuximab vedotin and the anti-PD-1 antibodies nivolumab and pembrolizumab. The identification of patients who should undergo allogeneic stem cell transplantation is another unsolved issue. The present article highlights the most relevant clinical trials and addresses controversial open questions in the treatment of cHL.