PET-guided omission of radiotherapy in early-stage unfavourable Hodgkin lymphoma (GHSG HD17): a multicentre, open-label, randomised, phase 3 trial

[Current Standards in the Treatment of Hodgkin Lymphoma]

This review discusses current trends in the treatment of Hodgkin lymphoma, focusing on optimizing therapy outcomes while minimizing toxicity. We summarize advances made by the incorporation of Brentuximab Vedotin into first line therapy for advanced stage Hodgkin lymphoma. Similarly, the incorporation of checkpoint-inhibition into first-line therapy holds great promise and early results suggest superior efficacy with reduced toxicity. In relapsed or refractory Hodgkin lymphoma, salvage chemotherapy followed by high-dose chemotherapy and autologous stem cell transplantation remains the standard approach. However, the remarkable efficacy of checkpoint inhibition in this setting has the potential to redefine treatment paradigms and obviate the need for HD-ASCT in select patients. Finally, we discuss the evolving landscape of nodular lymphocyte predominant Hodgkin lymphoma and reclassification to nodular lymphocyte predominant B-cell lymphoma, with increasing recognition of its distinct characteristics and treatment strategies.

Involved-site Radiation Therapy is Equally Effective and Less Toxic Than Involved-field Radiation Therapy in Patients Receiving Combined Modality Treatment for Early-stage Unfavorable Hodgkin Lymphoma-An Analysis of the Randomized Phase 3 HD17 Trial of the German Hodgkin Study Group

PURPOSE

Combined modality treatment with chemotherapy followed by consolidation radiation therapy (RT) provides excellent outcomes for patients with early-stage Hodgkin lymphoma. The international standard of care for consolidation RT, involved-site/involved-node radiation therapy (ISRT/INRT), has never been evaluated in a randomized phase 3 trial against the former standard involved-field radiation therapy (IFRT).

METHODS AND MATERIALS

In the multicenter phase 3 GHSG (German Hodgkin Study Group) HD17 trial, patients with early-stage unfavorable Hodgkin lymphoma were randomized between the standard Combined modality treatment group and a positron-emission tomography (PET)-guided group. In the standard group, patients received 2 cycles of escalated bleomycin, etoposide, doxorubicin, cyclophosphamide, vincristine, procarbazine, and prednisone (eBEACOPP) and 2 cycles of doxorubicin, bleomycin, vinblastine, and dacarbazine (ABVD) followed by 30 Gy IFRT. In the experimental group, patients received no further therapy if postchemotherapy PET was negative and 30 Gy GHSG INRT, comparable to and therefore termed here ISRT, if PET was positive. Here, we analyze the interim PET-positive patients in a post hoc analysis, and therefore the randomized comparison of IFRT versus INRT/ISRT.

RESULTS

A total of 1100 patients were randomized, of which 311 had a positive PET after chemotherapy. Kaplan-Meier estimates of 4-year progression-free survival were 96.8% (95% CI, 91.6%-98.8%) in the IFRT group and 95.4% (95% CI, 89.9%-97.9%; HR, 1.40; 95% CI, 0.44-4.42) in the ISRT group. The pattern of recurrence analyses indicated that none of the cases of disease progression or recurrence in the ISRT group would have been prevented by the use of IFRT. Acute grade 3/4 toxicities occurred in 8.5% of IFRT patients and 2.6% of ISRT patients (P = .03).

CONCLUSIONS

For the first time, consolidation INRT/ISRT was randomly compared with IFRT in a phase 3 trial. Regarding progression-free survival, no advantage of IFRT could be demonstrated. In summary, our data confirm the status of INRT/ISRT as the current standard of care.

Machine Learning-Based Survival Prediction Models for Progression-Free and Overall Survival in Advanced-Stage Hodgkin Lymphoma

PURPOSE

Patients diagnosed with advanced-stage Hodgkin lymphoma (aHL) have historically been risk-stratified using the International Prognostic Score (IPS). This study investigated if a machine learning (ML) approach could outperform existing models when it comes to predicting overall survival (OS) and progression-free survival (PFS).

PATIENTS AND METHODS

This study used patient data from the Danish National Lymphoma Register for model development (development cohort). The ML model was developed using stacking, which combines several predictive survival models (Cox proportional hazard, flexible parametric model, IPS, principal component, penalized regression) into a single model, and was compared with two versions of IPS (IPS-3 and IPS-7) and the newly developed aHL international prognostic index (A-HIPI). Internal model validation was performed using nested cross-validation, and external validation was performed using patient data from the Swedish Lymphoma Register and Cancer Registry of Norway (validation cohort).

RESULTS

In total, 707 and 760 patients with aHL were included in the development and validation cohorts, respectively. Examining model performance for OS in the development cohort, the concordance index (C-index) for the ML model, IPS-7, IPS-3, and A-HIPI was found to be 0.789, 0.608, 0.650, and 0.768, respectively. The corresponding estimates in the validation cohort were 0.749, 0.700, 0.663, and 0.741. For PFS, the ML model achieved the highest C-index in both cohorts (0.665 in the development cohort and 0.691 in the validation cohort). The time-varying AUCs for both the ML model and the A-HIPI were consistently higher in both cohorts compared with the IPS models within the first 5 years after diagnosis.

CONCLUSION

The new prognostic model for aHL on the basis of ML techniques demonstrated a substantial improvement compared with the IPS models, but yielded a limited improvement in predictive performance compared with the A-HIPI.

How I Follow Hodgkin Lymphoma in First Complete (Metabolic) Remission?

Hodgkin lymphoma is characterized by a high cure rate in the modern era of medicine regardless of stage, but patients suffer from a high risk of comorbidity associated with the administered therapy. The main aim of this review article is to assess and analyze the various comorbidities associated with Hodgkin lymphoma and address the survivorship of patients, including fertility, secondary cancers due to cardiovascular toxicity, and quality of life. Furthermore, this review explores the optimal strategy for detecting relapse. The treatment paradigm of Hodgkin lymphoma has shifted, with a paradigm shift toward achieving a high cure rate and low toxicity as a standard of care in this patient population. Checkpoint inhibitors, especially nivolumab, in combination with chemotherapy are increasingly being studied in the first line of therapy. However, their long-term toxicity remains to be assessed in longer follow-up. In conclusion, Hodgkin lymphoma survivors, regardless of their treatment, should be followed up individually by a multidisciplinary survivorship team in order to detect and properly treat the long-term side effects of therapy.

Is oligometastatic disease an applicable and useful concept in haematologic malignancies? A narrative review of radiation therapy standards, modern techniques, and innovations

PURPOSE

Haematologic malignancies are particular in that they can generally be cured, even when distant metastases are present at diagnosis, unlike solid malignancies. Systemic treatments, including chemotherapy, targeted therapies, and immunotherapy, are the standard of care with excellent results. The considerable progress made in the management of these diseases in the last 20years has redefined the role of radiation therapy as minor in many clinical situations. We propose a literature review of data, showing that radiation therapy still has a role in curative, salvage, and palliative therapy situations.

MATERIAL AND METHODS

A document and literature search was carried out in the following databases: Medline and ClinicalTrial.gov, for the terms "radiotherapy", "haematologic malignancies", "Hodgkin lymphoma", "non-Hodgkin lymphoma", "CAR T cells", "multiple myeloma", "solitary plasmocytoma", "intensity-modulated radiotherapy", "extracranial stereotactic body radiation therapy" and "proton therapy references".

RESULTS

Haemopathological malignancies include a wide range of diseases and radiation therapy indications have been assessed over the past 20years. Currently, radiation therapy is indicated for localized disease (solitary plasmocytoma), as an adjuvant (Hodgkin lymphoma), in palliative settings, or after systemic treatment in relapsed patients (chimeric antigen receptor [CAR] T-cells) with a low recurrence burden, which can therefore be considered "oligorecurrence". Radiation therapy, through total body irradiation, has important indications, thanks to its immunomodulatory and/or myeloablative effects. Moreover, recent technological developments have made possible significant improvement in safety, contributing to radiation therapy being positioned in the treatment strategy of several indications.

CONCLUSIONS

Given the effectiveness of systemic treatments in hematologic malignancies, the oligometastasis stage is of little importance. A curative intent after local radiation therapy, even advanced stage, is possible, both with residual disease for advanced Hodgkin lymphoma, aggressive non-Hodgkin lymphoma, or solitary plasmocytoma, and even without evidence of disease after chemotherapy for Hodgkin or non-Hodgkin lymphoma. The role of new treatments, such as CAR T cells, allows us to consider radiation therapy after systemic treatment of relapsed diseases with low volume recurrence, which can be considered oligorecurrence.

Prognostic Impact of Serum β2-Microglobulin Levels in Hodgkin Lymphoma Treated with ABVD or Equivalent Regimens: A Comprehensive Analysis of 915 Patients

The significance of serum beta-2 microglobulin (sβ2m) in Hodgkin lymphoma (HL) is controversial. We analyzed 915 patients with HL, who were treated with ABVD or equivalent regimens with or without radiotherapy. Sβ2m levels were measured by a radioimmunoassay (upper normal limit 2.4 mg/L). Sequential cutoffs (1.8-3.0 by 0.1 mg/L increments, 3.5 and 4.0 mg/L) were tested along with ROC analysis. The median sβ2m levels were 2.20 mg/L and were elevated (>2.4 mg/L) in 383/915 patients (41.9%). Higher sβ2m was associated with inferior freedom from progression (FFP) at all tested cutoffs. The best cutoff was 2.0 mg/L (10-year FFP 83% vs. 70%, p = 0.001), which performed better than the 2.4 mg/L cutoff ("normal versus high"). In multivariate analysis, sβ2m > 2.0 mg/L was an independent adverse prognostic factor in the whole patient population. In multivariate overall survival analysis, sβ2m levels were predictive at 2.0 mg/L cutoff in the whole patient population and in advanced stages. Similarly, sβ2m > 2.0 mg/L independently predicted inferior HL-specific survival in the whole patient population. Our data suggest that higher sβ2m is an independent predictor of outcome in HL but the optimal cutoff lies within the normal limits (i.e., at 2.0 mg/L) in this predominantly young patient population, performing much better than a "normal versus high" cutoff set at 2.4 mg/L.

Long-Term Follow-Up of the Response-Adapted Intergroup EORTC/LYSA/FIL H10 Trial for Localized Hodgkin Lymphoma

Clinical trials frequently include multiple end points that mature at different times. The initial report, typically based on the primary end point, may be published when key planned co-primary or secondary analyses are not yet available. Clinical Trial Updates provide an opportunity to disseminate additional results from studies, published in JCO or elsewhere, for which the primary end point has already been reported.The primary analysis of the Early positron emission tomography (ePET) Response-Adapted Treatment in localized Hodgkin Lymphoma H10 Trial demonstrated that in ePET-negative patients, the risk of relapse increased when involved-node radiotherapy (INRT) was omitted and that in ePET-positive patients, switching from doxorubicin, bleomycin, vinblastine, and dacarbazine (ABVD) to bleomycin, etoposide, doxorubicin, cyclophosphamide, vincristine, procarbazine, and prednisone (BEACOPPesc) significantly improved 5-year progression-free survival (PFS). Here, we report the final results of a preplanned analysis at a 10-year follow-up. In the favorable (F) ePET-negative group, the 10-year PFS rates were 98.8% versus 85.4% (hazard ratio [HR], 13.2; 95% CI, 3.1 to 55.8; P value for noninferiority = .9735; difference test P < .0001) in favor of ABVD + INRT; in the unfavorable (U) ePET-negative group, the 10-year PFS rates were 91.4% and 86.5% (HR, 1.52; 95% CI, 0.84 to 2.75; P value for noninferiority = .8577; difference test P = .1628). In ePET-positive patients, the difference in terms of PFS between standard ABVD and intensified BEACOPPesc was no longer statistically significant (HR, 0.67; 95% CI, 0.37 to 1.20; P = .1777). In conclusion, the present long-term analysis confirms that in ePET-negative patients, the omission of INRT is associated with lower 10-year PFS. Instead, in ePET-positive patients, no significant difference between standard and experimental arms emerged although intensification with BEACOPPesc was safe, with no increase in late adverse events, namely, second malignancies.

PET/CT Reconstruction and Its Impact on [Measures of] Metabolic Tumor Volume

RATIONALE AND OBJECTIVES

In oncological imaging, the use of metabolic tumor volume (MTV) for further prognostic differentiation and the development of risk adapted strategies appears promising. The aim of this analysis was to evaluate ultra-high definition (UHD) and ordered subset expectation maximization (OSEM) PET/CT reconstructions for their potential impact on different methods of MTV measurement.

MATERIALS AND METHODS

We analyzed positron emission tomography combined with computed tomography (PET/CT) scans of 40 Hodgkin lymphoma patients before first-line treatment who had undergone fluorodeoxyglucose (FDG) PET/CT. The MTVs were determined taking an SUV of 4.0 (MTV4.0) as a fixed threshold or 41% of the single hottest voxel (MTV41%) as an adaptive threshold for automated lymphoma delineation in both UHD and OSEM reconstructions. We then compared the absolute and relative differences between MTV4.0 and MTV41% in UHD and OSEM reconstructions. The relative distribution of MTV4.0 and MTV41% in relation to the reconstruction method applied was recorded and respective differences were tested for statistical significance using the paired sample t-test.

RESULTS

A comparison of MTV4.0 and MTV41% showed smaller relative and absolute differences in MTV between different reconstruction settings for the MTV4.0 method. Conversely, the absolute as well as the relative differences between MTVs obtained from different reconstructions settings were significantly greater when the MTV41% method was applied (p < 0001).

CONCLUSION

MTV4.0 brings higher robustness between different reconstruction settings, while with MTV41% the deviation between volumes obtained with different reconstruction settings is greater. For clinical routine and for multicenter settings, the MTV4.0 therefore appears most promising.

Management of limited-stage Hodgkin lymphoma

Hodgkin lymphoma (HL) is a rare type of B-cell malignancy with bimodal age distribution targeting young adults and elderly. Prognostic models are available to identify risk of recurrence and response to treatment. Currently, positron emission tomography scanning is most useful in optimizing therapy. Outcomes are generally excellent with standard chemotherapy or combined modality therapy. Balancing efficacy and the risk of late effects in Hodgkin lymphoma is essential, including early detection of potential complications. Incorporation of novel therapies such as brentuximab vedotin and checkpoint inhibitors are being explored in the frontline setting, having already demonstrated improved survival and tolerable toxicity in advanced HL. Furthermore, the addition of these agents have the potential to transform treatment paradigms for early-stage HL and may result in improved outcomes with decreased risks of late toxicities that continue to afflict long-term survivors. However, the patient population, sequencing, and combinations with cytotoxic chemotherapy all remain still standing questions as results of current and upcoming randomized trials are awaited. In this article, we discuss the current data on the approach to initial treatment of early-stage classical HL, review toxicity profiles, and examine upcoming novel therapy trials.

Prognostic value of baseline metabolic tumor volume (MTV) for forecasting chemotherapy outcome in early-stage unfavorable Hodgkin lymphoma: Data from the phase III HD17 trial

OBJECTIVES

The prognostic relevance of metabolic tumor volume (MTV) having recently been demonstrated in patients with early-stage favorable and advanced-stage Hodgkin lymphoma. The current study aimed to assess the potential prognostic value of 18 F-fluorodeoxyglucose (FDG) positron emission tomography (PET) in early-stage unfavorable Hodgkin lymphoma patients treated within the German Hodgkin Study Group HD17 trial.

METHODS

18 F-FDG PET/CT images were available for MTV analysis in 154 cases. We used three different threshold methods (SUV2.5 , SUV4.0 , and SUV41% ) to calculate MTV. Receiver-operating-characteristic analysis was performed to describe the value of these parameters in predicting an adequate therapy response. Therapy response was evaluated as PET negativity after 2 cycles of eBEACOPP followed by 2 cycles of ABVD.

RESULTS

All three threshold methods analyzed for MTV showed a positive correlation with the PET response after chemotherapy. Areas under the curve (AUC) were 0.70 (95% CI 0.53-0.87) and 0.65 (0.50-0.80) using the fixed thresholds of SUV4.0 and SUV2.5 , respectively, for MTV- calculation. The calculation of MTV using a relative threshold of SUV41% showed an AUC of 0.63 (0.47-0.79).

CONCLUSIONS

MTV does have predictive value after chemotherapy in early-stage unfavorable Hodgkin lymphoma, particularly when the fixed threshold of SUV4.0 is used for MTV calculation.

TRIAL REGISTRATION

ClinicalTrials.gov NCT01356680.

Integration of PET in DLBCL

F-fluorodeoxyglucose positron emission tomography-computerized tomography (18FDG-PET/CT) is the gold-standard imaging modality for staging and response assessment for most lymphomas. This review focuses on the utility of 18FDG-PET/CT, and its role in staging, prognostication and response assessment in diffuse large B-cell lymphoma (DLBCL), including emerging possibilities for future use.

A Quality Control Study on Involved Node Radiation Therapy in the European Organisation for Research and Treatment of Cancer/Lymphoma Study Association/Fondazione Italiana Linfomi H10 Trial on Stages I and II Hodgkin Lymphoma: Lessons Learned

PURPOSE

Involved node radiation therapy (INRT) was introduced in the European Organisation for Research and Treatment of Cancer/Lymphoma Study Association/Fondazione Italiana Linfomi H10 trial, a large multicenter trial in early-stage Hodgkin Lymphoma. The present study aimed to evaluate the quality of INRT in this trial.

METHODS AND MATERIALS

A retrospective, descriptive study was initiated to evaluate INRT in a representative sample encompassing approximately 10% of all irradiated patients in the H10 trial. Sampling was stratified by academic group, year of treatment, size of the treatment center, and treatment arm, and it was done proportional to the size of the strata. The sample was completed for all patients with known recurrences to enable future research on relapse patterns. Radiation therapy principle, target volume delineation and coverage, and applied technique and dose were evaluated using the EORTC Radiation Therapy Quality Assurance platform. Each case was reviewed by 2 reviewers and, in case of disagreement also by an adjudicator for a consensus evaluation.

RESULTS

Data were retrieved for 66 of 1294 irradiated patients (5.1%). Data collection and analysis were hampered more than anticipated by changes in archiving of diagnostic imaging and treatment planning systems during the running period of the trial. A review could be performed on 61 patients. The INRT principle was applied in 86.6%. Overall, 88.5% of cases were treated according to protocol. Unacceptable variations were predominately due to geographic misses of the target volume delineations. The rate of unacceptable variations decreased during trial recruitment.

CONCLUSIONS

The principle of INRT was applied in most of the reviewed patients. Almost 90% of the evaluated patients were treated according to the protocol. The present results should, however, be interpreted with caution because the number of patients evaluated was limited. Individual case reviews should be done in a prospective fashion in future trials. Radiation therapy Quality Assurance tailored to the clinical trial objectives is strongly recommended.

Significance of E-lesions in Hodgkin lymphoma and the creation of a new consensus definition: a report from SEARCH

The International Staging Evaluation and Response Criteria Harmonization for Childhood, Adolescent, and Young Adult Hodgkin Lymphoma (SEARCH for CAYAHL) seeks to provide an appropriate, universal differentiation between E-lesions and stage IV extranodal disease in Hodgkin lymphoma (HL). A literature search was performed through the PubMed and Google Scholar databases using the terms "Hodgkin disease," and "extranodal," "extralymphatic," "E lesions," "E stage," or "E disease." Publications were reviewed for the number of participants; median age and age range; diagnostic modalities used for staging; and the definition, incidence, and prognostic significance of E-lesions. Thirty-six articles describing 12 640 patients met the inclusion criteria. Most articles reported staging per the Ann Arbor (72%, 26/36) or Cotswolds modification of the Ann Arbor staging criteria (25%, 9/36), and articles rarely defined E-lesions or disambiguated "extranodal disease." The overall incidence of E-lesions for patients with stage I-III HL was 11.5% (1330/11 602 unique patients). Available stage-specific incidence analysis of 3888 patients showed a similar incidence of E-lesions in stage II (21.2%) and stage III (21.9%), with E-lesions rarely seen with stage I disease (1.1%). E-lesions likely remain predictive, but we cannot unequivocally conclude that identifying E-lesions in HL imparts prognostic value in the modern era of the more selective use of targeted radiation therapy. A harmonized E-lesion definition was reached based on the available evidence and the consensus of the SEARCH working group. We recommend that this definition of E-lesion be applied in future clinical trials with explicit reporting to confirm the prognostic value of E-lesions.

Advances in Hodgkin's lymphoma pharmacotherapy: a focus on histone deacetylase inhibitors

INTRODUCTION

Classical Hodgkin lymphomas (cHL) usually have excellent cure rates. Yet, for patients with refractory or relapsed cHL, prognosis deteriorates as the disease becomes resistant to subsequent lines of therapies: autologous stem cell transplantation, brentuximab vedotin, and checkpoint inhibitors. Immune escape and drug resistance are hallmarks of Hodgkin Reed Sternberg cell survival, prompting the need for additional therapeutic strategies. Histone modification-based combination is an effective clinical strategy.

AREAS COVERED

In this review, we discuss the different histone deacetylase (HDAC) inhibitor molecules that have been developed and studied in cancer therapy with a focus on cHL. We review their preclinical and clinical activities both as single agents and in combination studies. Literature search was conducted in PubMed, Google Scholar, and ClinicalTrials.gov databases, using search terms 'Hodgkin lymphoma,' 'histone deacetylase inhibitor', and variations on such (e.g. 'HDAC' and individual drug names) in combination using operators 'AND,' 'OR,' and 'NOT' according to Boolean logic.

EXPERT OPINION

HDAC inhibitors alone will not be sufficient for the treatment of R/RcHL, but given their disease control capacity, synergistic interaction with currently approved drugs, and ability to overcome drug resistance, particularly PD-1 inhibitors, we believe that HDACinhibitors will eventually become incorporated into the treatment armamentarium of cHL.

Quantitative PET-based biomarkers in lymphoma: getting ready for primetime

The use of functional quantitative biomarkers extracted from routine PET-CT scans to characterize clinical responses in patients with lymphoma is gaining increased attention, and these biomarkers can outperform established clinical risk factors. Total metabolic tumour volume enables individualized estimation of survival outcomes in patients with lymphoma and has shown the potential to predict response to therapy suitable for  risk-adapted treatment approaches in clinical trials. The deployment of machine learning tools in molecular imaging research can assist in recognizing complex patterns and, with image classification, in tumour identification and segmentation of data from PET-CT scans. Initial studies using fully automated approaches to calculate metabolic tumour volume and other PET-based biomarkers have demonstrated appropriate correlation with calculations from experts, warranting further testing in large-scale studies. The extraction of computer-based quantitative tumour characterization through radiomics can provide a comprehensive view of phenotypic heterogeneity that better captures the molecular and functional features of the disease. Additionally, radiomics can be integrated with genomic data to provide more accurate prognostic information. Further improvements in PET-based biomarkers are imminent, although their incorporation into clinical decision-making currently has methodological shortcomings that need to be addressed with confirmatory prospective validation in selected patient populations. In this Review, we discuss the current knowledge, challenges and opportunities in the integration of quantitative PET-based biomarkers in clinical trials and the routine management of patients with lymphoma.

Incorporating Monoclonal Antibodies into the First-Line Treatment of Classical Hodgkin Lymphoma

The long-term survival of Hodgkin lymphoma (HL) patients treated according to the current standard of care is excellent. Combined-modality schedules (ABVD plus radiotherapy) in early-stage disease, along with treatment intensity adaptation to early metabolic response assessed by PET/CT in advanced stage HL, have been the cornerstones of risk stratification and treatment decision-making, minimizing treatment-related complications while keeping efficacy. Nevertheless, a non-negligible number of patients are primary refractory or relapse after front-line treatment. Novel immunotherapeutic agents, namely Brentuximab Vedotin (BV) and immune checkpoint inhibitors (CPI), have already shown outstanding efficacy in a relapsed/refractory setting in recent landmark studies. Several phase 2 single-arm studies suggest that the addition of these agents in the frontline setting could further improve long-term disease control permitting one to reduce the exposure to cytotoxic drugs. However, a longer follow-up is needed. At the time of this writing, the only randomized phase 3 trial so far published is the ECHELON-1, which compares 1 to 1 BV-AVD (Bleomycin is replaced by BV) with standard ABVD in untreated advanced-stage III and IV HL. The ECHELON-1 trial has proven that BV-AVD is safe and more effective both in terms of long-term disease control and overall survival. Just recently, the results of the S1826 SWOG trial demonstrated that the combination nivolumab-AVD (N-AVD) is better than BV-AVD, while preliminary results of other randomized ongoing phase 3 trials incorporating anti-PD-1 in this setting will be soon available. The aim of this review is to present the recent data regarding these novel agents in first-line treatment of HL and to highlight current and future trends which will hopefully reshape the overall management of this disease.

Interim PET-guided treatment for early-stage NLPHL: a subgroup analysis of the randomized GHSG HD16 and HD17 studies

The optimal first-line treatment for nodular lymphocyte-predominant Hodgkin lymphoma (NLPHL) diagnosed in early stages is largely undefined. We, therefore, analyzed 100 NLPHL patients treated in the randomized HD16 (early-stage favorable; n = 85) and HD17 (early-stage unfavorable; n = 15) studies. These studies investigated the omission of consolidation radiotherapy (RT) in patients with a negative interim positron emission tomography (iPET) (ie, Deauville score <3) after chemotherapy (HD16: 2× doxorubicin, bleomycin, vinblastine, and dacarbazine [ABVD]; HD17: 2× escalated bleomycin, etoposide, doxorubicin, cyclophosphamide, vincristine, procarbazine, and prednisone [BEACOPP] plus 2× ABVD). Patients with NLPHL treated in the HD16 and HD17 studies had 5-year progression-free survival (PFS) rates of 90.3% and 92.9%, respectively. Thus, the 5-year PFS did not differ significantly from that of patients with classical Hodgkin lymphoma treated within the same studies (HD16: P = .88; HD17: P = .50). Patients with early-stage favorable NLPHL who had a negative iPET after 2× ABVD and did not undergo consolidation RT tended to have a worse 5-year PFS than patients with a negative iPET who received consolidation RT (83% vs 100%; P = .05). There were 10 cases of NLPHL recurrence. However, no NLPHL patient died during follow-up. Hence, the 5-year overall survival rate was 100%. Taken together, contemporary Hodgkin lymphoma-directed treatment approaches result in excellent outcomes for patients with newly diagnosed early-stage NLPHL and, thus, represent valid treatment options. In early-stage favorable NLPHL, consolidation RT appears necessary after 2× ABVD to achieve the optimal disease control irrespective of the iPET result.

Clinical applications of circulating tumor DNA in Hodgkin lymphoma

Hodgkin lymphoma is a B-cell lymphoma often affecting young adults. Outcomes following intensive chemo- and radiotherapy are generally favourable but leave patients at high risk for early and late toxicities frequently reducing quality of life. Relapsed/refractory disease is regularly difficult to treat and ultimately results in death in a relevant subset of patients. Current strategies for risk stratification and response evaluation rely on clinical features and imaging only, and lack discriminatory power to detect patients at risk for disease progression. Here, we explore how circulating tumor DNA sequencing might help to overcome these shortcomings. We provide an overview over recent technical and methodological developments and suggest potential use cases for different clinical situations. Circulating tumor DNA sequencing offers the potential to significantly augment current risk stratification strategies with the ultimate goal of further individualizing treatment strategies for patients with HL.

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.

Are we reaching the maximum cure rate for Hodgkin lymphoma?

The treatment of Hodgkin lymphoma, using cytotoxic chemotherapy and selective radiotherapy, has resulted in progressively increasing cure rates over the last 40 years. Recent studies have been directed at using response-adapted approaches to modulate treatment according to the responses seen using functional imaging, with the aim of balancing the probability of cure against the toxicity of more extensive treatments, in particular the risks of infertility, second malignancy and cardiovascular disease. The results of these studies suggest that we have reached the limits of what might be expected from the conventional treatments, but the arrival of antibody-based therapies, specifically antibody-drug conjugates and immune checkpoint blocking antibodies, now holds out the prospect of further improvements. The next challenge will be to select those groups for whom they are most needed.

Radiation Therapy in the German Hodgkin Study Group HD 16 and HD 17 Trials: Quality Assurance and Dosimetric Analysis for Hodgkin Lymphoma in the Modern Era

Purpose

Radiation therapy (RT) is an integral part of treatment concepts for early-stage Hodgkin lymphoma. This analysis reports on RT quality in the recent HD16 and 17 trials of the German Hodgkin Study Group (GHSG).

Methods and Materials

All RT plans of involved-node radiation therapy (INRT) in HD 17 were requested for analysis, along with 100 and 50 involved-field radiation therapy (IFRT) plans in HD 16 and 17, respectively. A structured assessment regarding field design and protocol adherence was performed by the reference radiation oncology panel of the GHSG.

Results

Overall, 100 (HD 16) and 176 (HD 17) patients were eligible for analysis. In HD 16, 84% of RT series were evaluated as correct, with significant improvement compared with the predecessor studies (P < .001). In HD 17, 76.1% of INRT cases revealed a correct RT design compared with 69.0% of IFRT-cases, which was superior to previous studies (P < .001). Comparing INRT and IFRT, we found no significant differences in the percentage of any deviation (P = .418) or major deviations (P = .466). Regarding dosimetry, INRT was accompanied by an improvement in thyroid doses. Comparing different RT techniques, we found that intensity-modulated RT showed a reduction of high doses in the lung at the expense of an increased low-dose exposure in HD 17.

Conclusions

The latest study generation of the GHSG demonstrates an improved quality in RT. A modern INRT design could be established without deterioration in quality. On a conceptual level, an individual consideration of the appropriate RT technique has to be performed.

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.

European Association of Nuclear Medicine (EANM) Focus 4 consensus recommendations: molecular imaging and therapy in haematological tumours

Given the paucity of high-certainty evidence, and differences in opinion on the use of nuclear medicine for hematological malignancies, we embarked on a consensus process involving key experts in this area. We aimed to assess consensus within a panel of experts on issues related to patient eligibility, imaging techniques, staging and response assessment, follow-up, and treatment decision-making, and to provide interim guidance by our expert consensus. We used a three-stage consensus process. First, we systematically reviewed and appraised the quality of existing evidence. Second, we generated a list of 153 statements based on the literature review to be agreed or disagreed with, with an additional statement added after the first round. Third, the 154 statements were scored by a panel of 26 experts purposively sampled from authors of published research on haematological tumours on a 1 (strongly disagree) to 9 (strongly agree) Likert scale in a two-round electronic Delphi review. The RAND and University of California Los Angeles appropriateness method was used for analysis. Between one and 14 systematic reviews were identified on each topic. All were rated as low to moderate quality. After two rounds of voting, there was consensus on 139 (90%) of 154 of the statements. There was consensus on most statements concerning the use of PET in non-Hodgkin and Hodgkin lymphoma. In multiple myeloma, more studies are required to define the optimal sequence for treatment assessment. Furthermore, nuclear medicine physicians and haematologists are awaiting consistent literature to introduce volumetric parameters, artificial intelligence, machine learning, and radiomics into routine practice.

Interim FDG-PET/CT for Response Assessment of Lymphoma

The clinical use and prognostic value of interim FDG-PET/CT (iPET/CT), which is performed after treatment initiation but prior to its completion, varies by lymphoma subtype. Evidence supporting the prognostic value of iPET/CT is more robust for classical Hodgkin lymphoma (cHL), and in this lymphoma subtype, response-adapted treatment approaches guided by iPET/CT are a widely used standard of care for first-line therapy. The data supporting use of iPET/CT among patients with non-Hodgkin lymphoma (NHL) is less well-established, but failure to achieve complete metabolic response on iPET/CT is generally considered a poor prognostic factor with likely consequences for progression free survival. This review will present the available evidence supporting use of iPET/CT in lymphoma patients, particularly as it relates to prognostication and the ability to inform response-adapted treatment strategies. The latter will be addressed through a discussion on the major iPET-response adapted clinical trials with mention of ongoing trials. Special attention will be given to cHL and a few subtypes of NHL, including diffuse large B cell lymphoma (DLBCL), follicular lymphoma (FL), and peripheral T cell lymphoma (PTCL).

The clinical features, management and outcomes of lymphoma in pregnancy: A multicentre study by the Australasian Lymphoma Alliance

Lymphoma in pregnancy (LIP) presents unique clinical, social and ethical challenges; however, the evidence regarding this clinical scenario is limited. We conducted a multicentre retrospective observational study reporting on the features, management, and outcomes of LIP in patients diagnosed between January 2009 and December 2020 at 16 sites in Australia and New Zealand for the first time. We included diagnoses occurring either during pregnancy or within the first 12 months following delivery. A total of 73 patients were included, 41 diagnosed antenatally (AN cohort) and 32 postnatally (PN cohort). The most common diagnoses were Hodgkin lymphoma (HL; 40 patients), diffuse large B-cell lymphoma (DLBCL; 11) and primary mediastinal B-cell lymphoma (PMBCL; six). At a median follow up of 2.37 years, the 2- and 5-year overall survival (OS) for patients with HL were 91% and 82%. For the combined DLBCL and PMBCL group, the 2-year OS was 92%. Standard curative chemotherapy regimens were successfully delivered to 64% of women in the AN cohort; however, counselling regarding future fertility and termination of pregnancy were suboptimal, and a standardised approach to staging lacking. Neonatal outcomes were generally favourable. We present a large multicentre cohort of LIP reflecting contemporary practice and identify areas in need of ongoing research.

Biology-Guided Radiation Therapy

Biology-guided radiation therapy is an emerging field whereby delivery of external beam radiotherapy incorporates biological/molecular imaging to inform radiation treatment. At present, there is evidence for the use of functional imaging such as PET to evaluate treatment response in patients both during and after radiation treatment as well as to provide a method of adapting or selecting patient-specific treatments. Examples in thoracic, gastrointestinal, and hematologic malignancies are provided. Improvements in PET metrics, thresholds, and novel radiotracers will further move this novel field forward.

Treatment approaches for nodular lymphocyte-predominant Hodgkin lymphoma

Nodular lymphocyte-predominant Hodgkin lymphoma (NLPHL) is a rare variant of Hodgkin lymphoma characterized by a persistent risk of relapse but an excellent overall survival. Historically, it was treated similarly to classic Hodgkin lymphoma, but efforts have been made to deintensify treatment due to risk of late toxicity associated with intensive therapy. For patients with completely resected stage IA NLPHL, no further treatment may be considered, particularly for pediatric patients. For those with stage I-II NLPHL without risk factors such as B symptoms, sites>2, or variant pattern histology, lower intensity treatment with radiotherapy or chemotherapy alone may be sufficient. However, combined modality therapy is a standard treatment for favorable and unfavorable risk stage I-II NLPHL associated with excellent progression-free and overall survival rates. For patients with advanced stage NLPHL, the optimal chemotherapy is not defined, but R-CHOP appears to be an effective treatment. Efforts to study NLPHL through multicenter collaborative efforts are crucial to develop evidence based and individualized treatments for patients with NLPHL.

Positron Emission Tomography-Adapted Therapy in Bulky Stage I/II Classic Hodgkin Lymphoma: CALGB 50801 (Alliance)

PURPOSE

Patients with bulky stage I/II classic Hodgkin lymphoma (cHL) are typically treated with chemotherapy followed by radiation. Late effects associated with radiotherapy include increased risk of second cancer and cardiovascular disease. We tested a positron emission tomography (PET)-adapted approach in patients with bulky, early-stage cHL, omitting radiotherapy in patients with interim PET-negative (PET-) disease and intensifying treatment in patients with PET-positive (PET+) disease.

METHODS

Eligible patients with bulky disease (mass > 10 cm or 1/3 the maximum intrathoracic diameter on chest x-ray) received two cycles of doxorubicin, bleomycin, vinblastine, and dacarbazine (ABVD) followed by interim fluorodeoxyglucose PET (PET2). Patients with PET2-, defined as 1-3 on the 5-point scale, received four additional cycles of doxorubicin, bleomycin, vinblastine, and dacarbazine. Patients with PET2+ received four cycles of escalated bleomycin, etoposide, doxorubicin, cyclophosphamide, vincristine, procarbazine, and prednisone followed by 30.6 Gy involved-field radiation.

RESULTS

Of 94 evaluable patients, 53% were female with median age 30 years (range, 18-58 years). Eight-five (90%) had stage II disease, including 48 (51%) with stage IIB/IIBE. Seventy-eight (78%) were PET2- and 21 (22%) were PET2+. The predominant toxicity was neutropenia, with 9% of patients developing febrile neutropenia and one developing sepsis. The primary end point of 3-year progression-free survival (PFS) was 93.1% in PET2- and 89.7% in PET2+ patients. Three-year overall survival was 98.6% and 94.4%, respectively. The estimated hazard ratio comparing PFS of patients with PET2+ and patients with PET2- was 1.03 (85% upper bound 2.38) and was significantly less than the null hypothesis of 4.1 (one-sided P = .04).

CONCLUSION

Our study of PET-adapted therapy in bulky stage I/II cHL met its primary goal and was associated with an excellent 3-year PFS rate of 92.3% in all patients, with the majority being spared radiotherapy and exposure to intensified chemotherapy.

Response assessment by positron emission tomography-computed tomography as compared with contrast-enhanced computed tomography in childhood Hodgkin lymphoma can reduce the need for radiotherapy in low- and middle-income countries

INTRODUCTION

The InPOG-HL-15-01, a multicentric prospective study, used a risk-stratified and response-based approach with doxorubicin, bleomycin, vinblastine, and dacarbazine (ABVD) backbone to treat children and adolescents with newly diagnosed Hodgkin lymphoma (HL) and reduce the use of radiation therapy (RT). Children/adolescents with bulky disease or inadequate response at early response assessment (ERA) after two cycles of chemotherapy were assigned to receive RT. For ERA, positron emission tomography computed tomography (PET-CT) was recommended but not mandatory in view of limited access. This study aimed to compare the impact of using contrast-enhanced computed tomography (CECT) and PET-CT on treatment decisions and outcomes.

METHODOLOGY

396 patients were enrolled and 382 had an ERA at the assigned time point. Satisfactory response was defined as Deauville score 3 or less for patients undergoing PET-CT and complete response (CR)/very good partial response (VGPR) for patients undergoing CECT. Outcomes of interest incorporate 5 year event-free survival (EFS), EFS including abandonment (EFSa), and overall survival (OS).

RESULTS

At ERA, satisfactory response was documented in 277 out of 382 (72.5%) participants and this was significantly higher in PET-CT (151 out of 186, 81.2%) as compared with CECT-based assessments (126 out of 196, 64.3%) respectively (p value < .001). Amongst the 203 patients with nonbulky disease (wherein the indication for RT was entirely dependent on ERA), 96 out of 114 (84.2%) and 61 out of 89 (68.5%) patients achieved a satisfactory response according to the PET-CT and CECT (p value = .008) respectively and hence a lesser proportion of patients in the PET-CT arm received RT. Despite a lower usage of RT the 5 year OS of both groups, ERA based on CECT (91.8%) versus PET-CT (94.1%) was comparable (p value = .391) and so was the 5 year EFS (86.7 vs. 85.5%, p value = .724).

CONCLUSION

Use of PET-CT as the modality for ERA is more likely to indicate a satisfactory response as compared with CECT and thereby decreases the need for RT in response-based treatment algorithm for HL-afflicted children. The reduction in the application of RT did not impact the overall outcome and plausibly would lower the risk of delayed toxic effects.

Brentuximab Vedotin Plus AVD for First-Line Treatment of Early-Stage Unfavorable Hodgkin Lymphoma (BREACH): A Multicenter, Open-Label, Randomized, Phase II Trial

PURPOSE

The prognosis of patients with early-stage unfavorable Hodgkin lymphoma remains unsatisfactory. We assessed the efficacy and safety of brentuximab vedotin plus doxorubicin, vinblastine, and dacarbazine (BV-AVD) in previously untreated, early-stage unfavorable Hodgkin lymphoma (ClinicalTrials.gov identifier: NCT02292979).

METHODS

BREACH is a multicenter, randomized, open-label, phase II trial. Eligible patients were age 18-60 years with ≥ 1 unfavorable EORTC/LYSA criterion. Patients were randomly assigned (2:1) to four cycles of BV-AVD or standard doxorubicin, bleomycin, vincristine, and dacarbazine (ABVD), followed by 30 Gy involved node radiotherapy. The primary end point was the positron emission tomography (PET) response rate after two cycles by expert independent review using the Deauville score. The study was designed to test if the PET-negative rate after two cycles of BV-AVD was superior to 75%. We hypothesized a 10% increase in the PET-negative rate after two cycles of BV-AVD.

RESULTS

Between March 2015 and October 2016, 170 patients were enrolled. After two cycles, the primary end point of the study was met: 93 (82.3%; 90% CI, 75.3 to 88.0) of 113 patients in the BV-AVD arm were PET-negative (Deauville score 1-3) compared with 43 (75.4%; 90% CI, 64.3% to 84.5%) of 57 in the ABVD arm. The 2-year progression-free survival (PFS) was 97.3% (95% CI, 91.9 to 99.1) and 92.6% (95% CI, 81.4% to 97.2%) in the BV-AVD and ABVD arms, respectively. High total metabolic tumor volume was associated with a significantly shorter PFS (hazard ratio, 17.9; 95% CI, 2.2 to 145.5; P < .001). For patients with high total metabolic tumor volume, the 2-year PFS rate was 90.9% (95% CI, 74.4 to 97.0) and 70.7% (95% CI, 39.4% to 87.9%) in the BV-AVD and ABVD arms, respectively.

CONCLUSION

BV-AVD demonstrated an improvement in the PET-negative rate compared with ABVD after two cycles.

Long-term outcomes for patients with Hodgkin lymphoma at increased risk of progression or relapse

Although advancements in the treatment of Hodgkin lymphoma have enabled many patients to be cured of their disease, about half of patients who relapse or experience refractory disease ultimately fail treatment, even after autologous stem cell transplant. Risk stratification is crucial to enable escalation of therapy in patients at increased risk for progression while allowing for less intensive therapy in lower risk groups. Utilization of clinical factors to inform risk scores was common practice, but this historical approach has been supplemented by PET/CT risk adapted management. Long-term outcomes of high-risk patients have improved over the decades with advancements in therapy and emergence of novel agents including antibody-drug conjugates and immune checkpoint inhibitors, yet further research is urgently needed. Herein, we review long-term outcomes of patients with Hodgkin lymphoma at increased risk for progression or relapse and discuss limitations of current risk strategies.

Radiation doses to mediastinal organs at risk in early-stage unfavorable Hodgkin lymphoma- a risk stratified analysis of the GHSG HD17 trial

Introduction

The German Hodgkin Study Group (GHSG) HD17 trial established the omission of radiotherapy (RT) for patients with early-stage unfavorable Hodgkin lymphoma being PET-negative after 2 cycles of BEACOPP escalated plus 2 cycles of ABVD. This patient group reveals heterogeneity in characteristics and disease extent which prompted us to perform a decisive dosimetric analysis according to GHSG risk factors. This may help to tailor RT individually balancing risks and benefits.

Methods

For quality assurance, RT-plans were requested from the treating facilities (n= 141) and analyzed centrally. Dose-volume histograms were scanned either paper-based or digitally to obtain doses to mediastinal organs. These were registered and compared according to GHSG risk factors.

Results

Overall, RT plans of 176 patients were requested, 139 of which had dosimetric information on target volumes within the mediastinum. Most of these patients were stage II (92.8%), had no B-symptoms (79.1%) and were aged < 50 years (89.9%). Risk factors were present in 8.6% (extranodal involvement), 31.7% (bulky disease), 46.0% (elevated erythrocyte sedimentation rate) and 64.0% (three involved areas), respectively. The presence of bulky disease significantly affected the mean RT doses to the heart (p=0.005) and to the left lung (median: 11.3 Gy vs. 9.9 Gy; p=0.042) as well as V5 of the right and left lung, respectively (median right lung: 67.4% vs. 51.0%; p=0.011; median left lung: 65.9% vs. 54.2%; p=0.008). Significant differences in similar organs at risk parameters could be found between the sub-cohorts with the presence or absence of extranodal involvement, respectively. In contrast, an elevated erythrocyte sedimentation rate did not deteriorate dosimetry significantly. No association of any risk factor with radiation doses to the female breast was found.

Conclusion

Pre-chemotherapy risk factors may help to predict potential RT exposure to normal organs and to critically review treatment indication. Individualized risk-benefit evaluations for patients with HL in early-stage unfavorable disease are mandatory.

Patterns of care and outcomes of early stage I-II Hodgkin lymphoma treated with or without radiation therapy

Omission of radiotherapy in the upfront management of early-stage classic Hodgkin lymphoma (cHL) has become more common with time. We report patterns of care and outcomes of stage I-II cHL treated with chemotherapy (CT) only versus CT and radiotherapy (combined modality therapy, CMT). From the National Cancer Database, we identified 28,327 early-stage cHL patients treated with CT (n = 15,798) or CMT (n = 12,529) from 2004 to 2018. CMT utilization declined over the period from 58% to 34%. With median follow-up of 6.2 years, the 5- and 10-year overall survival for CT versus CMT was 93.3% versus 96.9% (p < 0.001) and 88.7% versus 93.5% (p < 0.001), respectively. On multivariable analysis, uninsured (OR 0.75, p < 0.001) and Black patients (OR 0.86, p = 0.02) were less likely to receive CMT, and treatment with CT was predictive of death (OR 2.0, p < 0.001). This report highlights real-world outcomes in early-stage cHL, with worse survival with CT and notable disparities in CMT utilization.

Checkpoint Inhibitors and the Changing Face of the Relapsed/Refractory Classical Hodgkin Lymphoma Pathway

PURPOSE OF REVIEW

Checkpoint inhibitors (CPIs) targeting PD1 are highly active in relapsed/refractory classical Hodgkin lymphoma. A plethora of recent studies, often small and non-randomised, have raised many questions about how to optimally integrate these into clinical practice. We aim to discuss the use of CPIs in different relapsed/refractory settings in an effort to better define their role and highlight areas of research.

RECENT FINDINGS

CPIs have shown efficacy at first relapse, as salvage pre- and post-autologous (ASCT) and allogeneic stem cell transplant (alloSCT) and as maintenance post-ASCT. Immune-related adverse events require careful attention, especially when used peri-alloSCT, where it is associated with hyperacute graft-versus-host disease. Newer PD1 inhibitors, as well as strategies to overcome CPI resistance, are being tested. CPIs are increasingly deployed at earlier points in the classical Hodgkin lymphoma pathway. Whilst progress is clearly being made, randomised studies are required to more clearly define the optimal positioning of these agents.

Circulating tumor DNA in Hodgkin lymphoma

Somatic mutations of genes involved in NF-κB, PI3K/AKT, NOTCH, and JAK/STAT signaling pathways play an important role in the pathogenesis of Hodgkin lymphoma (HL). HL tumor cells form only about 5% of the tumor mass; however, it was shown that HL tumor-derived DNA could be detected in the bloodstream. This circulating tumor DNA (ctDNA) reflects the genetic profile of HL tumor cells and can be used for qualitative and quantitative analysis of tumor-specific somatic DNA mutations within the concept of liquid biopsy. Overall, the most frequently mutated gene in HL is STAT6; however, the exact spectrum of mutations differs between individual HL histological subtypes. Importantly, reduction of ctDNA plasma levels after initial treatment is highly correlated with prognosis. Therefore, ctDNA shows great promise as a novel tool for non-invasive tumor genome analysis for biomarker driven therapy as well as for superior minimal residual disease monitoring and treatment resistance detection. Here, we summarize the recent advancements of ctDNA analysis in HL with focus on ctDNA detection methodologies, genetic profiling of HL and its clonal evolution, and the emerging prognostic value of ctDNA.

Characterizing the immune microenvironment for nodular lymphocyte-predominant Hodgkin lymphoma

The microenvironment of nodular lymphocyte-predominant Hodgkin lymphoma (NLPHL) and its relationship to presentation and outcomes has not been widely investigated. In a large cohort of patients with NLPHL, Hartmann and colleagues showed an association between microenvironmental factors and clinical presentation serving to inform future studies evaluating the prognostic impact of the immunoarchitectural patterns and cell types present. Commentary on: Hartmann et al. Tumor cell characteristics and microenvironment composition correspond to clinical presentation in newly diagnosed nodular lymphocyte predominant Hodgkin lymphoma. Br J Haematol 2022 (Online ahead of print). doi: 10.1111/bjh.18376.

[Hematological pathologies: the most successful model of de-escalation in radiotherapy]

The proportion of patients irradiated in the context of malignant hematological pathologies decreased over the last decades. The main causes are the late side effects of the historical series and the new therapeutic strategies aiming to relay radiotherapy to the rank of option. At the same time, radiotherapy has been modernised, target volumes and total doses have been drastically reduced. Hodgkin's lymphomas, indolent follicular lymphomas and primary cerebral lymphomas are the main witnesses of this therapeutic deflation.

Tumour cell characteristics and microenvironment composition correspond to clinical presentation in newly diagnosed nodular lymphocyte-predominant Hodgkin lymphoma

Different studies have characterized the microenvironment and its prognostic impact in classic Hodgkin lymphoma whereas such analyses are pending for nodular lymphocyte-predominant Hodgkin lymphoma (NLPHL). We thus investigated characteristics of tumour cells and microenvironment in NLPHL and evaluated possible correlations with the clinical presentation. Lymph node samples from 152 NLPHL patients who had first-line treatment within the randomized German Hodgkin Study Group HD16-HD18 trials were available and analysed with regard to IgD status and nuclear size of the tumour cells as well as presence of PD1-positive follicular T helper cells and CD163-positive macrophages in the microenvironment. While large tumour cell nuclei and high numbers of PD1-positive follicular T helper cells in the microenvironment were more common in patients presenting with early/intermediate stages than in patients with advanced-stage disease (p < 0.0001, unpaired t-test; p = 0.0022, Mann-Whitney test), no differences between risk groups were observed in terms of the IgD status of the tumour cells and the content of CD163-positive macrophages in the microenvironment. PD1-positive follicular T helper cells were present in both cases with typical and variant growth patterns and rosetting around the tumour cells was observed in 96% of patients, indicating an important role of PD1-positive follicular T helper cells in NLPHL.

Practice changing data and emerging concepts from recent radiation therapy randomised clinical trials

INTRODUCTION

Oncology treatments are constantly and rapidly evolving. We aimed at highlighting the latest radiation therapy practice changing trials and emerging concepts, through an overview of recent randomised clinical trials (RCTs).

MATERIALS AND METHODS

Requests were performed in the Medline database to identify all publications reporting radiation therapy RCTs from 2018 to 2021.

RESULTS

Recent RCTs sustained the role of newer combinatorial strategies through radioimmunotherapy for early stage or metastatic lung cancer, newer pro-apoptotic agents (e.g. debio 1143 in locoregionally advanced head and neck squamous cell carcinoma) or nanoparticles (e.g. NBTXR3 in locally advanced soft-tissue sarcoma). High-tech radiotherapy allows intensifying treatments and gaining ground in some indications through the development of stereotactic body radiotherapy for example. First randomised evidence on personalised radiation therapy through imaging-based (¹⁸FDG positron emission tomography-computed tomography for lung cancer or early stage unfavourable Hodgkin lymphoma, PMSA positron emission tomography-computed tomography or magnetic resonance imaging for high-risk prostate cancer) or biological biomarkers (PSA for prostate cancer, HPV for head and neck cancer, etc) were conducted to more tailored treatments, with more favourable outcomes. Patients' quality of life and satisfaction appeared to be increasing aims. RCTs have validated (ultra)hypofractionated schemes in many indications as for breast, prostate or rectal cancer, resulting in equivalent outcomes and toxicities, more convenient for patients and favouring shared decision making.

CONCLUSION

Radiation therapy is a dynamic field of research, and many RCTs have greatly impacted therapeutic standards over the last years. Investments in radiotherapy research should facilitate the transfer of innovation to clinic.

Predictive value of baseline metabolic tumor volume in early-stage favorable Hodgkin Lymphoma - Data from the prospective, multicenter phase III HD16 trial

Background

¹⁸F -fluorodeoxyglucose (FDG) positron emission tomography (PET) plays an important role in the staging and response assessment of lymphoma patients. Our aim was to explore the predictive relevance of metabolic tumor volume (MTV) and total lesion glycolysis (TLG) in patients with early stage Hodgkin lymphoma treated within the German Hodgkin Study Group HD16 trial.

Methods

¹⁸F-FDG PET/CT images were available for MTV and TLG analysis in 107 cases from the HD16 trial. We calculated MTV and TLG using three different threshold methods (SUV_4.0, SUV_41% and SUV_140%L), and then performed receiver-operating-characteristic analysis to assess the predictive impact of these parameters in predicting an adequate therapy response with PET negativity after 2 cycles of chemotherapy.

Results

All three threshold methods analyzed for MTV and TLG calculation showed a positive correlation with the PET response after 2 cycles chemotherapy. The largest area under the curve (AUC) was observed using the fixed threshold of SUV_4.0 for MTV- calculation (AUC 0.69 [95% CI 0.55–0.83]) and for TLG-calculation (AUC 0.69 [0.55–0.82]). The calculations for MTV and TLG with a relative threshold showed a lower AUC: using SUV_140%L AUCs of 0.66 [0.53–0.80] for MTV and 0.67 for TLG [0.54–0.81]) were observed, while with SUV_41% an AUC of 0.61 [0.45–0.76] for MTV, and an AUC 0.64 [0.49–0.80]) for TLG were seen.

Conclusions

MTV and TLG do have a predictive value after two cycles ABVD in early stage Hodgkin lymphoma, particularly when using the fixed threshold of SUV_4.0 for MTV and TLG calculation.

Trial registration

ClinicalTrials.gov NCT00736320.

Cardiotoxicity model-based patient selection for Hodgkin lymphoma proton therapy

INTRODUCTION

Hodgkin lymphoma (HL) is a highly curable hematological malignancy. Consolidation radiation therapy techniques have made significant progresses to improve organ-at-risk sparing in order to reduce late radiation-induced toxicity. Recent technical breakthroughs notably include intensity modulated proton therapy (IMPT), which has demonstrated a major dosimetric benefit at the cardiac level for mediastinal HL patients. However, its implementation in clinical practice is still challenging, notably due to the limited access to proton therapy facilities. In this context, the purpose of this study was to estimate the benefit of IMPT for HL proton therapy for diverse cardiac adverse events and to propose a general frame for mediastinal HL patient selection strategy for IMPT based on cardiotoxicity reduction, patient clinical factors, and IMPT treatment availability.

MATERIAL AND METHODS

This retrospective dosimetric study included 30 mediastinal HL patients treated with VMAT. IMPT plans were generated on the initial simulation scans. Dose to the heart, to the left ventricle and to the valves were retrieved to calculate the relative risk (RR) of ischemic heart disease (IHD), congestive heart failure (CHF) and valvular disease (VD). Composite relative risk reduction (cRRR) of late cardiotoxicity, between VMAT and IMPT, were calculated as the weighted mean of relative risk reduction for IHD, CHF and VD, calculated across a wide range of cardiovascular risk factor combinations. The proportion of mediastinal HL patients who could benefit from IMPT was estimated in European countries, based on the country population and on the number of active gantries, to propose country-specific cRRR thresholds for patient selection.

RESULTS

Compared with VMAT, IMPT significantly reduced average mean doses to the heart (2.36 Gy vs 0.99 Gy, p < 0.01), to the left ventricle (0.67 Gy vs 0.03, p < 0.01) and to the valves (1.29 Gy vs. 0.06, p < 0.01). For a HL patient without cardiovascular risk factor other than anthracycline-based chemotherapy, the relative risks of late cardiovascular complications were significantly lower after IMPT compared with VMAT for ischemic heart disease (1.07 vs 1.17, p < 0.01), for congestive heart failure (2.84 vs. 3.00, p < 0.01), and for valvular disease (1.01 vs. 1.06, p < 0.01). The median cRRR of cardiovascular adverse events with IMPT was 4.8%, ranging between 0.1% and 30.5%, depending on the extent of radiation fields and on the considered cardiovascular risk factors. The estimated proportion of HL patients currently treatable with IMPT in European countries with proton therapy facilities ranged between 8.0% and 100% depending on the country, corresponding to cRRR thresholds ranging from 24.0% to 0.0%.

CONCLUSION

While a statistically significant clinical benefit is theoretically expected for ischemic heart disease, cardiac heart failure and valvular disease for mediastinal HL patients with IMPT, the overall cardiotoxicity risk reduction is notable only for a minority of patients. In the context of limited IMPT availability, this study proposed a general model-based selection approach for mediastinal HL patient based on calculated cardiotoxicity reduction, taking into consideration patient clinical characteristics and IMPT facility availability.

High-risk stage IIB Hodgkin lymphoma treated in the H10 and AHL2011 trials: total metabolic tumor volume is a useful risk factor to stratify patients at baseline

Stage IIB Hodgkin lymphoma (HL) patients, with a mediastinum-to-thorax (M/T) ratio of ≥0.33 or extranodal localization have a poor prognosis and are treated either as limited or advanced stage. We compared these two approaches in patients included in two randomized phase III trials enrolling previously untreated early (H10) or advanced stage HL (AHL2011). We included HL patients with Ann-Arbor stage IIB with M/T ≥0.33 or extranodal involvement enrolled in the H10 or AHL2011 trials with available positron emission tomography at baseline (PET0) and after two cycles of chemotherapy (PET2). Baseline total metabolic tumor volume (TMTV) was calculated using the 41% SUVmax method. PET2 response assessment used the Deauville score. One hundred and fourty-eight patients were eligible, including 83 enrolled in the AHL2011 trial and 65 in the H10 trial. The median TMTV value was 155.5 mL (range, 8.3-782.9 mL), 165.6 mL in AHL2011 and 147 mL in H10. PET2 positivity rates were 16.9% (n=14) and 9.2% (n=6) in AHL2011 and H10 patients, respectively. With a median follow-up of 4.1 years (95% confidence interval [CI]: 3.9-4.4), overall 4-year PFS was 88.0%, 87.0% in AHL2011 and 89.2% in H10. In univariate and mutivariate analyses, baseline TMTV and PET2 response influenced significantly progression-free survival (hazard ratio [HR]=4.94, HR=3.49 respectively). Notably, among the 16 patients who relapsed, 13 (81%) had a baseline TMTV baseline ≥155 mL. Upfront ABVD plus radiation therapy or upfront escBEACOPP without radiotherapy provide similar patient's outcome in high-risk stage IIB HL. TMTV is useful to stratify these patients at baseline.

Second Malignancies in Patients with Hodgkin’s Lymphoma: Half a Century of Experience

Purpose

Therapeutic improvements for Hodgkin’s Lymphoma (HL) has resulted in excellent survival outcomes. Thus, patients are increasing susceptible to developing secondary malignancy (SM) a feared iatrogenic complication.

Materials & Methods

We evaluated the SM risk in a cohort of patients with HL treated over a 50-year period. In total, 1653 patients were treated for HL from 1956 to 2009 at a tertiary-cancer-center. A cumulative incidence function was used to quantify SM risk and the Fine and Gray competing risk model was used to identify disease and treatment related correlates.

Results

Two-hundred-ninety patients (19%) developed SMs. Paradoxically, SM risk was higher in the modern era with 20-year cumulative incidence rates of 11.1%, 11.9%, 17% and 21.8%, for patients treated <1970, 1971–1986, 1986–1995 and 1996–2009, respectively. We hypothesized that the disproportionately high rate of early deaths in the early era may skew the assessment of SM risks, a much-delayed event. When the analysis was restricted to patients with early-stage favorable HL treated >1980, we found a reversal of the trend, especially on the risk of solid tumor, with a hazard ratio of 0.57 (p = 0.0651) in patients treated after 1996.

Conclusion

Our findings highlight the limitations of comparing the risk of a late event between groups with disparate rates of early deaths, despite the use of a competing risk model. When partially corrected for, patients treated in the more recent time period experienced a lower solid tumor risk.

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

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

Positron Emission Tomography-Driven Strategy in Advanced Hodgkin Lymphoma: Prolonged Follow-Up of the AHL2011 Phase III Lymphoma Study Association Study

PURPOSE

The AHL2011 study (ClinicalTrials.gov identifier: NCT01358747) demonstrated that a positron emission tomography (PET)-driven de-escalation strategy after two cycles of bleomycin, etoposide, doxorubicin, cyclophosphamide, vincristine, procarbazine, and prednisone (BEACOPP) provides similar progression-free survival (PFS) and overall survival (OS) and reduces early toxicity compared with a nonmonitored standard treatment. Here, we report, with a prolonged follow-up, the final study results.

METHODS

Patients with advanced Hodgkin lymphoma (stage III, IV, or IIB with mediastinum/thorax ratio > 0.33 or extranodal involvement) age 16-60 years were prospectively randomly assigned between 6 × BEACOPP and a PET-driven arm after 2 × BEACOPP delivering 4 × ABVD (doxorubicin, bleomycin, vinblastine, and dacarbazine) in PET2- and 4 × BEACOPP in PET2+ patients. PET performed after four cycles of chemotherapy had to be negative to complete the planned treatment.

RESULTS

In total, 823 patients were enrolled including 413 in the standard arm and 410 in the PET-driven arm. With a 67.2-month median follow-up, 5-year PFS (87.5% v 86.7%; hazard ratio [HR] = 1.07; 95% CI, 0.74 to 1.57; P = .67) and OS (97.7% in both arms; HR = 1.012; 95% CI, 0.50 to 2.10; P = .53) were similar in both randomization arms. In the whole cohort, full interim PET assessment predicted patients' 5-year PFS (92.3% in PET2-/PET4-, 75.4% [HR = 3.26; 95% CI, 18.3 to 5.77] in PET2+/PET4- and 46.5% [HR = 12.4; 95% CI, 7.31 to 19.51] in PET4+ patients, respectively; P < .0001) independent of international prognosis score. Five-year OS was also affected by interim PET results, and PET2+/PET4- patients (93.5%; HR = 3.3; 95% CI, 1.07 to 10.1; P = .036) and PET4+ patients (91.9%; HR = 3.756; 95% CI, 1.07 to 13.18; P = .038) had a significant lower OS than PET2-/PET4- patients (98.2%). Twenty-two patients (2.7%) developed a second primary malignancy, 13 (3.2%) and 9 (2.2%) in the standard and experimental arms, respectively.

CONCLUSION

The extended follow-up confirms the continued efficacy and favorable safety of AHL2011 PET-driven strategy, which is noninferior to standard six cycles of BEACOPP. PET4 provides additional prognostic information to PET2 and allows identifying patients with particularly poor prognosis.