Development and Implementation of Proton Therapy for Hodgkin Lymphoma: Challenges and Perspectives

Proton Therapy Reduces the Effective Dose to Immune Cells in Mediastinal Hodgkin Lymphoma Patients

Purpose

Effective dose to circulating immune cells (EDIC) is associated with survival in lung and esophageal cancer patients. This study aimed to evaluate the benefit of intensity-modulated proton therapy (IMPT) for EDIC reduction compared with volumetric modulated arc therapy (VMAT) in mediastinal Hodgkin lymphoma (mHL) patients.

Materials and Methods

Ten consecutive mHL patients treated with involved-site IMPT after frontline chemotherapy were included. The mean dose to the heart, lung, and liver and the integral dose to the body were obtained, and we calculated EDIC based on these variables. The effective dose to circulating immune cells was compared between IMPT and VMAT schedules.

Results

The median EDIC was reduced from 1.93 Gy (range: 1.31-3.87) with VMAT to 1.08 Gy (0.53-2.09) with IMPT (P < .01). Integral dose reduction was the main driver of EDIC reduction with IMPT, followed by lung sparing.

Conclusion

Intensity-modulated proton therapy significantly reduced EDIC in mHL patients undergoing consolidation involved-site radiation therapy. Integral dose reduction combined with improved lung sparing was the main driver of EDIC reduction with IMPT.

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.

Primary ophthalmic natural killer/T-cell lymphoma: A population-based study

BACKGROUND

Ophthalmic lymphomas, a subgroup of extra-nodal lymphomas, have seen an increase in incidence in recent decades. Of these, the NK/T-cell lymphoma (NKTL) subtype is particularly aggressive. Though prevalent mostly in Asian patients, data on ophthalmic NKTL is still limited, especially in the western population. This study aimed to provide an additional analysis of primary ophthalmic NKTL using the Surveillance, Epidemiology, and End Results (SEER) database.

METHODS

A retrospective analysis was performed on the SEER database covering records from 2000 to 2020. Patients diagnosed with extranodal NKTL originating primarily from an ophthalmic structure were identified.

RESULTS

Out of 4540 ophthalmic lymphomas registered in the SEER database between 2000 and 2020, 9 cases (0.2%) corresponded to ophthalmic NKTL, occurring in patients with a median age of 67 years. The majority of these patients underwent chemotherapy (88.8%) and radiotherapy (66.6%). The 6-month overall survival (OS) and cancer-specific survival (CSS) were both at 50.8%, dropping significantly at the 2-year follow-up.

CONCLUSION

Primary orbital NKTL has a notably severe prognosis. An early diagnosis is important due to the aggressive nature of NKTL.

Tissue Reactions and Mechanism in Cardiovascular Diseases Induced by Radiation

The long-term survival rate of cancer patients has been increasing as a result of advances in treatments and precise medical management. The evidence has accumulated that the incidence and mortality of non-cancer diseases have increased along with the increase in survival time and long-term survival rate of cancer patients after radiotherapy. The risk of cardiovascular disease as a radiation late effect of tissue damage reactions is becoming a critical challenge and attracts great concern. Epidemiological research and clinical trials have clearly shown the close association between the development of cardiovascular disease in long-term cancer survivors and radiation exposure. Experimental biological data also strongly supports the above statement. Cardiovascular diseases can occur decades post-irradiation, and from initiation and development to illness, there is a complicated process, including direct and indirect damage of endothelial cells by radiation, acute vasculitis with neutrophil invasion, endothelial dysfunction, altered permeability, tissue reactions, capillary-like network loss, and activation of coagulator mechanisms, fibrosis, and atherosclerosis. We summarize the most recent literature on the tissue reactions and mechanisms that contribute to the development of radiation-induced cardiovascular diseases (RICVD) and provide biological knowledge for building preventative strategies.

Promising drugs and treatment options for pediatric and adolescent patients with Hodgkin lymphoma

Currently-available therapies for newly-diagnosed pediatric and adolescent patients with Hodgkin lymphoma result in >95% survival at 5 years. Long-term survivors may suffer from long-term treatment-related side effects, however, so the past 20 years have seen clinical trials for children and adolescents with HL gradually abandon the regimens used in adults in an effort to improve this situation. Narrower-field radiotherapy can reduce long-term toxicity while maintaining good tumor control. Various risk-adapted chemo-radiotherapy strategies have been used. Early assessment of tumor response with interim positron emission tomography and/or measuring metabolic tumor volume has been used both to limit RT in patients with favorable characteristics and to adopt more aggressive therapies in patients with a poor response. Most classical Hodgkin's lymphoma relapses occur within 3 years of initial treatment, while relapses occurring 5 years or more after diagnosis are rare. As the outcome for patients with relapsed/refractory classical Hodgkin lymphoma remains unsatisfactory, new drugs have been proposed for its prevention or treatment. This review summarizes the important advances made in recent years in the management of pediatric and adolescent with classical Hodgkin lymphoma, and the novel targeted treatments for relapsed and refractory classical Hodgkin lymphoma.

Pediatric Plasma Cell Neoplasms: A Population-Based Study

INTRODUCTION

Plasma cell neoplasms are exceptionally rare in the pediatric population; the demographic characteristics and the clinical outcomes of plasma cell neoplasms in this population are currently poorly understood. The aim of this study was to provide a comprehensive analysis of pediatric plasma cell neoplasms, based on the United-States Surveillance, Epidemiology, and End Results (SEER) program registries.

MATERIALS AND METHODS

All pediatric patients (aged less than 20 years) diagnosed with a malignant plasma cell neoplasm were retrieved from the SEER Program database (18 registries), collecting patient records between 2000 and 2018. The plasma cell neoplasm type, sex, age at diagnosis, year of diagnosis, race and origin, primary disease site, follow-up duration, and vital status at the last known contact were retrieved and analyzed.

RESULTS

The age-adjusted incidence rate of plasma cell neoplasms for 1,000,000 person-years was 0.06 for the pediatric population (compared with 90.6 for the adult population). The types of pediatric plasma cell neoplasms predominantly consisted of plasmacytomas, with 11 solitary extraosseous plasmacytoma (42.3%) and 7 solitary bone plasmacytoma (26.9%), while plasma cell myelomas represented only a minority of the neoplasms (8 patients; 30.8%). Most plasmacytomas were localized in the head and neck region. Hispanic patients represented 50% of the pediatric plasma cell neoplasm cases (but only 11.1% of adult cases, P < .01). Female-to-Male ratio was 1.36. Five-year overall survival rates were 88.2% (95% confidence interval [95% CI]: 74.2%-100%) for pediatric plasmacytoma and 36.5% (95% CI: 12.4%-100%) for pediatric plasma cell myeloma (P = .013).

CONCLUSION

This first population-based study of pediatric plasma cell neoplasms underlines the rarity of this entity and demonstrates its unique characteristics, including the significant predominance of plasmacytomas, of female patients, and of patients from hispanic origin, and the poor clinical outcomes of pediatric plasma cell myeloma patients.

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.