Role of Consolidative Radiation Therapy After Autologous Hematopoietic Cell Transplantation for the Treatment of Relapsed or Refractory Hodgkin Lymphoma

Optimizing salvage therapy for Hodgkin lymphoma: progress and future challenges

INTRODUCTION

Despite clear advancements in the management of classical Hodgkin lymphoma (cHL) over the past decade including better risk stratification, the usage of 18F-flurodeoxyglucose positron emission tomography (FDG-PET)-guided approaches and incorporation of novel agents, approximately one-third of the patients will relapse. Important themes have been recently explored in the first salvage setting including the recognition of the positive prognostic value of a negative pre-autologous stem cell transplantation (ASCT) FDG-PET response and the incorporation of novel agents such as brentuximab vedotin (BV) and immune checkpoint inhibitors (CPIs) as salvage regimens to improve patient outcomes.

AREAS COVERED

The evolving treatment paradigm in optimizing salvage therapy in relapsed refractory cHL (RR-cHL) is discussed, including a vision to the future. The methodology included a literature search on PubMed using keywords. Selected articles were screened and evaluated by the authors of this review.

EXPERT OPINION

Achieving a complete remission by FDG-PET pre-ASCT is the most important prognostic factor in obtaining disease control and subsequent cure, and therefore should be a key goal of any salvage regimen. Although data from randomized controlled trials are currently lacking, retrospective evidence demonstrate superior event free survival with CPI-based regimens compared to conventional chemotherapy or BV-based therapy.

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.

Hodgkin lymphoma: Focus on evolving treatment paradigms

Hodgkin lymphoma (HL) is a highly curable B-cell malignancy of germinal center origin. Biologically it is a hematologic malignancy that is highly dependent on the immune microenvironment and utilizes immune escape through upregulation of the programmed-death ligands on the neoplastic cells. Despite being highly curable, consensus is lacking nationally and internationally about the optimal approach to management, particularly in limited-stage disease. The addition of brentuximab vedotin and checkpoint inhibitors for the management of HL has led to a rapidly changing treatment landscape. Further studies should be done to include these novel agents at all stages of disease to determine improvements in frontline cure rates and long-term toxicity.

Consolidative radiotherapy for residual fluorodeoxyglucose activity on day +30 post CAR T-cell therapy in non-Hodgkin lymphoma

Majority of non-Hodgkin lymphoma (NHL) patients who achieve partial response (PR) or stable disease (SD) to CAR T-cell therapy (CAR T) on day +30 progress and only 30% achieve spontaneous complete response (CR). This study is the first to evaluate the role of consolidative radiotherapy (cRT) for residual fluorodeoxyglucose (FDG) activity on day +30 post- CAR T in NHL. We retrospectively reviewed 61 patients with NHL who received CAR T and achieved PR or SD on day +30. Progression-free survival (PFS), overall survival (OS), and local relapse-free survival (LRFS) were assessed from CAR T infusion. cRT was defined as comprehensive - treated all FDG-avid sites - or focal. Following day +30 positron emission tomography scan, 45 patients were observed and 16 received cRT. Fifteen (33%) observed patients achieved spontaneous CR, and 27 (60%) progressed with all relapses involving initial sites of residual FDG activity. Ten (63%) cRT patients achieved CR, and four (25%) progressed with no relapses in the irradiated sites. The 2-year LRFS was 100% in the cRT sites and 31% in the observed sites (P<0.001). The 2-year PFS was 73% and 37% (P=0.025) and the 2-year OS was 78% and 43% (P=0.12) in the cRT and observation groups, respectively. Patients receiving comprehensive cRT (n=13) had superior 2- year PFS (83% vs. 37%; P=0.008) and 2-year OS (86% vs. 43%; P=0.047) compared to observed or focal cRT patients (n=48). NHL patients with residual FDG activity following CAR T are at high risk of local progression. cRT for residual FDG activity on day +30 post-CAR T appears to alter the pattern of relapse and improve LRFS and PFS.

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.

Nivolumab and brentuximab vedotin with or without bendamustine for R/R Hodgkin lymphoma in children, adolescents, and young adults

Children, adolescents, and young adults (CAYA) with relapsed/refractory (R/R) classic Hodgkin lymphoma (cHL) without complete metabolic response (CMR) before autologous hematopoietic cell transplantation (auto-HCT) have poor survival outcomes. CheckMate 744, a phase 2 study for CAYA (aged 5-30 years) with R/R cHL, evaluated a risk-stratified, response-adapted approach with nivolumab plus brentuximab vedotin (BV) followed by BV plus bendamustine for patients with suboptimal response. Risk stratification was primarily based on time to relapse, prior treatment, and presence of B symptoms. We present the primary analysis of the standard-risk cohort. Data from the low-risk cohort are reported separately. Patients received 4 induction cycles with nivolumab plus BV; those without CMR (Deauville score >3, Lugano 2014) received BV plus bendamustine intensification. Patients with CMR after induction or intensification proceeded to consolidation (high-dose chemotherapy/auto-HCT per protocol). Primary end point was CMR any time before consolidation. Forty-four patients were treated. Median age was 16 years. At a minimum follow-up of 15.6 months, 43 patients received 4 induction cycles (1 discontinued), 11 of whom received intensification; 32 proceeded to consolidation. CMR rate was 59% after induction with nivolumab plus BV and 94% any time before consolidation (nivolumab plus BV ± BV plus bendamustine). One-year progression-free survival rate was 91%. During induction, 18% of patients experienced grade 3/4 treatment-related adverse events. This risk-stratified, response-adapted salvage strategy had high CMR rates with limited toxicities in CAYA with R/R cHL. Most patients did not require additional chemotherapy (bendamustine intensification). Additional follow-up is needed to confirm durability of disease control. This trial was registered at www.clinicaltrials.gov as #NCT02927769.

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.

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.

Impact of Radiation Therapy After High Dose Chemotherapy and Autologous Hematopoietic Stem Cell Transplantation in Patients With Relapsed/Refractory Lymphomas: A Single Center Experience

INTRODUCTION

After high dose chemotherapy (HDC) and autologous stem cell transplantation (auto-SCT), in patients with relapsed/refractory diffuse large B cell lymphoma (DLBCL) and Hodgkin lymphoma (HL), involved field radiation therapy (RT) for consolidation and residual/progressive disease (PD) eradication is a common practice.

MATERIALS AND METHODS

Retrospective single-institution cohort analysis to evaluate the impact of early RT after HDC auto-SCT.

RESULTS

Between 1996 and October 2019, 153 patients (43 DLBCL, 110 HL) underwent RT after HDC auto-SCT. Males 95 (62%), females 58 (38%), median age 24 years. Indications for RT was consolidation 65%: residual disease eradication 16%: and PD eradication 19%. For DLBCL, the median overall survival (OS) for the above indications was not reached (NR):NR:2 months and the KM 5-year OS was 72.6%:64.3%:12.5% respectively (P ≤ .000). Pair-wise analysis showed that consolidation versus residual disease eradication had no difference (P = .88) but both were superior to PD disease eradication (P ≤ 000 and P = .005 respectively). For HL, indication for RT was, 54%:23%:24% respectively. The median OS was NR:NR:28.8 months and KM 5-year OS was 82.3%:78%:30% respectively (P ≤ .000). Pair-wise analysis showed that consolidation versus residual disease eradication had no difference (P = .98) but both were superior to the PD eradication group (P ≤ 000). RT was well tolerated with no significant long-term toxicity.

CONCLUSION

Post HDC auto-SCT RT was well tolerated. DLBCL and HL patients with residual disease treated with the RT had similar long-term survival as those who received RT for consolidation. RT failed to improve the poor survival in patients with post-HDC auto-SCT PD.

Improving outcomes after autologous transplantation in relapsed/refractory Hodgkin lymphoma: a European expert perspective

Autologous stem cell transplantation (ASCT) is a well-established approach to treatment of patients with relapsed/refractory (R/R) Hodgkin lymphoma (HL) recommended by both the European Society for Medical Oncology and the National Comprehensive Cancer Network based on the results from randomized controlled studies. However, a considerable number of patients who receive ASCT will progress/relapse and display suboptimal post-transplant outcomes. Over recent years, a number of different strategies have been assessed to improve post-ASCT outcomes and augment HL cure rates. These include use of pre- and post-ASCT salvage therapies and post-ASCT consolidative therapy, with the greatest benefits demonstrated by targeted therapies, such as brentuximab vedotin. However, adoption of these new approaches has been inconsistent across different centers and regions. In this article, we provide a European perspective on the available treatment options and likely future developments in the salvage and consolidation settings, with the aim to improve management of patients with HL who have a high risk of post-ASCT failure. CONCLUSIONS: We conclude that early intervention with post-ASCT consolidation improves outcomes in patients with R/R HL who require ASCT. Future approvals of targeted agents are expected to further improve outcomes and provide additional treatment options in the coming age of personalized medicine.

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.

Risk of Pneumonitis and Outcomes After Mediastinal Proton Therapy for Relapsed/Refractory Lymphoma: A PTCOG and PCG Collaboration

PURPOSE

Despite high response rates, there has been reluctance to use radiation therapy for patients with relapsed/refractory (r/r) Hodgkin (HL) or aggressive non-Hodgkin lymphoma (NHL) given concerns for subacute and late toxicities. Symptomatic pneumonitis, a subacute toxicity, has an incidence of 17% to 24% (≥grade 2) even with intensity modulated radiation therapy. Proton therapy (PT), which has no exit radiation dose, is associated with a lower dose to lung compared with other radiation techniques. As risk of radiation pneumonitis is associated with lung dose, we evaluated whether pneumonitis rates are lower with PT.

METHODS AND MATERIALS

Within an international, multi-institutional cohort, we retrospectively evaluated the incidence and grade of radiation pneumonitis (National Cancer Institute Common Terminology Criteria for Adverse Events v4) among patients with r/r HL or NHL treated with PT.

RESULTS

A total of 85 patients with r/r lymphoma (66% HL, 34% NHL; 46% primary chemorefractory) received thoracic PT from 2009 to 2017 in the consolidation (45%) or salvage (54%) setting. Median dose was 36 Gy(RBE). Before PT, patients underwent a median of 1 salvage systemic therapy (range, 0-4); 40% received PT within 4 months of transplant. With a median follow-up of 26.3 months among living patients, 11 patients developed symptomatic (grade 2) pneumonitis (12.8%). No grade 3 or higher pneumonitis was observed. Dose to lung, including mean lung dose, lung V5, and V20, significantly predicted risk of symptomatic pneumonitis, but not receipt of brentuximab, history of bleomycin toxicity, sex, or peritransplant radiation.

CONCLUSIONS

PT for relapsed/refractory lymphoma was associated with favorable rates of pneumonitis compared with historical controls. We confirm that among patients treated with PT, pneumonitis risk is associated with mean lung and lung V20 dose. These findings highlight how advancements in radiation delivery may improve the therapeutic ratio for patients with relapsed/refractory lymphoma. PT may be considered as a treatment modality for patients with relapsed/refractory lymphoma in the consolidation or salvage setting.

Relapsing/refractory HL after autotransplantation: which treatment?

For advanced-stage Hodgkin lymphoma (HL), front-line chemotherapy, alone or in combination with radiotherapy, leads to 5-year progression-free survival (PFS) rates and freedom-from-treatment failure (FFTF) rates of 70-85%, regardless of the chemotherapy regimen applied. Patients with HL experiencing disease progression during or within 3 months of front-line therapy (primary refractory) and patients whose disease relapses after a complete response have a second chance of treatment. The standard of care for relapsed or refractory HL is second-line chemotherapy followed by autologous stem cell transplantation (ASCT), which can induce long-term remission in approximately 40-50% of patients. However, HL recurrence occurs in about 50% of patients after ASCT, usually within the first year, and represents a significant therapeutic challenge. Allogeneic transplantation from HLA-matched donors represents the standard of care for patients with HL relapsing after- or refractory to ASCT.

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.

Treatment patterns and disease outcomes for pediatric patients with refractory or recurrent Hodgkin lymphoma treated with curative-intent salvage radiotherapy

BACKGROUND AND PURPOSE

The use of radiotherapy (RT) for pediatric patients with Hodgkin lymphoma (HL) experiencing disease progression or recurrence (15%) is controversial. We report treatment patterns and outcomes for pediatric patients with refractory/recurrent HL (rrHL) treated with curative-intent RT.

MATERIALS AND METHODS

Forty-six patients with rrHL treated with salvage RT at our institution were identified. All received risk-adapted, response-based frontline therapy and were retrieved with cytoreductive regimens followed by RT to failure sites, with or without autologous hematopoietic cell transplantation (AHCT). Cumulative incidence (CIN) of local failure (LF) and survival were estimated after salvage RT and regression models determined predictors of LF after salvage RT.

RESULTS

RT was administered as part of frontline therapy in 70% of patients, omitted for early response assessment in 13%, or deferred for primary progression in 17%. AHCT was omitted in 20% of patients. Median initial and salvage dose/site were 25.5 Gy and 30.6 Gy, respectively. Eight patients experienced progression. Two died without progression (median follow-up from salvage RT = 3.8 years). The 5-year CIN of LF after salvage RT was 17.7% (95% confidence interval [CI], 8.2-30.2%). The 5-year freedom from subsequent treatment failure and overall survival (OS) was 80.1% (95% CI, 69.2-92.6%) and 88.5% (95% CI, 79.5-98.6%), respectively. Inadequate response to salvage systemic therapy (p = 0.048) and male sex (p = 0.049) were significantly associated with LF after salvage RT.

CONCLUSION

rrHL is responsive to salvage RT, with low LF rates after moderate doses. OS is excellent, despite refractory disease. Initial salvage therapy response predicts subsequent LF.

Should all patients with HL who relapse after ASCT be considered for allogeneic SCT? A consult, yes; a transplant, not necessarily

This article has a companion Point by Peggs.

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.

Treatment-Resistant Hodgkin Lymphoma: Defining the Role of Autologous Transplantation

Autologous hematopoietic stem cell transplant (AHCT) remains the current standard of care for patients with relapsed or refractory Hodgkin lymphoma (HL) after frontline chemotherapy. However, treatment paradigms for HL are rapidly changing with positron emission tomography-adapted therapy, as well as the incorporation of brentuximab vedotin and checkpoint inhibitors into frontline, salvage, and maintenance therapy for HL. Patients who relapse or are refractory to these novel agents are likely to have different responses and outcomes with AHCT than the 3-year event-free survivals of 50% historically reported with AHCT for patients failing conventional combination chemotherapy. This article reviews the current data on the efficacy of AHCT, pretransplant prognostic markers, pretransplant salvage regimens, peritransplant radiation therapy, and posttransplant maintenance therapy in classic HL. Future research should reexamine the efficacy, timing, risk factors, pretransplant salvage regimens, and maintenance approaches posttransplant in the era of brentuximab vedotin and checkpoint inhibitors for HL.

Fertility preservation in Hodgkin's lymphoma patients that undergo targeted molecular therapies: an important step forward from the chemotherapy era

In total, 80%-90% of Hodgkin's lymphoma (HL) patients are curable with combination chemoradiotherapy. Due to improvements in therapeutic strategies, 50% of all relapsed/refractory patients may undergo complete clinical responses and have long-term survival. Treatment options for HL are effective, but may have a negative impact on post-chemotherapy fertility. Thus, cryopreservation of semen prior to treatment is recommended for male patients. For female patients, assisted reproductive techniques (ART) consult and fertility preservation should be offered as a therapeutical option. In the last years, new targeted molecules have been available for HL treatment. These new drugs showed a high rate of overall responses in the setting of heavily pretreated patients, most of them in relapse after autologous stem cell transplantation, a group previously considered very poor risk. Up to 50% of patients have a complete response and an improved overall survival. Future studies will address the usefulness of novel molecules as a frontline therapy. Considering the high response and survival rates with monoclonal antibody-based therapeutics, fertility has become a concerning issue for long-term HL survivors. As progress has been made regarding ART, with the rigorous steps planned for HL patients, more survivors will become parents.

Transplant strategies in relapsed/refractory Hodgkin lymphoma

The majority of patients with Hodgkin lymphoma (HL) are cured with initial therapy. However, high-dose therapy with autologous hematopoietic cell transplant (AHCT) allows for the cure of an additional portion of patients with relapsed or primary refractory disease. Positron emission tomography-negative complete remission before AHCT is critical for long-term disease control. Several salvage options are available with comparable response rates, and the choice can be dependent of comorbidities and logistics. Radiation therapy can also improve the remission rate and is an important therapeutic option for selected patients. Brentuximab vedotin (BV) maintenance after AHCT is beneficial in patients at high risk for relapse, especially those with more than 1 risk factor, but can have the possibility of significant side effects, primarily neuropathy. Newer agents with novel mechanisms of action are under investigation to improve response rates for patients with subsequent relapse, although are not curative alone. BV and the checkpoint inhibitors nivolumab and pembrolizumab are very effective with limited side effects and can bridge patients to curative allogeneic transplants (allo-HCT). Consideration for immune-mediated toxicities, timing of allogeneic hematopoietic cell transplant based on response, and the potential for increased graft-versus-host disease remain important. Overall, prospective investigations continue to improve outcomes and minimize toxicity for relapsed or primary refractory HL patients.

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

Relapsed and refractory Hodgkin lymphoma (HL) challenges clinicians to devise treatment strategies that are effective and safe. This problem is particularly prominent in an era when de-escalation trials are designed to minimize therapeutic toxicities in both early- and advanced-stage disease. Radiation therapy is the single most effective treatment modality for HL, and its integration into salvage regimens, or its independent use in select patients, must be understood to maximize our success in treating these patients. The complexity of treating relapsed or refractory HL derives from the spectrum of primary treatment approaches currently in use that creates heterogeneity in both treatment exposure and the potential toxicities of salvage therapy. Patients can have relapsed or refractory disease after limited or aggressive primary therapy (with or without radiation therapy), at early or delayed time points, with limited or extensive disease volumes, and with varying degrees of residual morbidity from primary therapy. Their response to salvage systemic therapy can be partial or complete, and the use of consolidative stem cell transplantation is variably applied. New biologics and immunotherapeutic approaches have broadened but also complicated salvage treatment approaches. Through all of this, radiation therapy remains an integral component of treatment for many patients, but it must be used effectively and judiciously. The purpose of this review is to describe the different treatment scenarios and provide guidance for radiation dose, volume, and timing in patients with relapsed or refractory HL.