Milgrom, Sarah A.

Abstract Modern radiation therapy (RT) technologies allow for improved sparing of normal tissues, decreasing the risk of both acute and long-term toxicities. Existing RT dose constraints for prospective trials within the National Clinical Trials Network (NCTN) were formulated in the context of solid malignancies. As patients with hematologic malignancies are often treated with lower RT doses and are usually younger with more favorable prognoses, customized dose constraints are needed. The NRG Oncology Hematologic Malignancies Working Group (NRG HEME) commissioned a review of existing organ-at-risk (OAR) constraints from published primary literature, the NRG Center for Innovation in Radiation Oncology (CIRO), and national guidelines. Customized constraints were developed by iterative review by NRG HEME. Final recommendations were approved by radiation oncology representatives from all the lymphoma NCTN groups (NRG Oncology, Children’s Oncology Group, Alliance, ECOG-ACRIN, SWOG, Canadian Cancer Trials Group). For 49 OARs, a strict recommended constraint was determined, of which 20 were not present in CIRO. Of the remaining 29 constraints, 20 were lower, 2 were the same, and 5 used different metrics; 2 were higher than at least 1 CIRO trial constraint. Acceptable variations were determined and unacceptable variations were added for select critical OARs for plan scoring. While doses to OARs without explicit unacceptable variations should not exceed acceptable variations, violations should not be considered for plan quality assessment on trials. This consensus list of standard OAR constraints should be incorporated for all future NCTN trials in hematologic malignancies. Strict dose constraints will minimize long-term toxicities in this patient population.

Summary In adults with classic Hodgkin lymphoma (cHL), metabolic tumour volume (MTV) is valuable for risk stratification. This systematic review explored the role of volumetric parameters in children, adolescents and young adults (CAYA) with cHL. This systematic review was performed according to the Preferred Reporting Items for Systematic Reviews and Meta‐Analyses (PRISMA) method. Five databases were searched on 16 October 2024. Eligible studies were peer‐reviewed manuscripts, written in English, published since database inception that included patients ≤21 years of age with a diagnosis of cHL treated with chemotherapy ± radiotherapy with a baseline 18 F‐Fluorodeoxyglucose (F‐FDG) PET/CT scan for MTV quantification. The search strategy identified 3669 studies, of which 35 were eligible for inclusion. Fifteen studies (43%) evaluated a cohort exclusively ≤21 years of age. All eight studies that explored the association of baseline PET parameters with known risk factors identified a significant correlation. Nine of 12 papers (75%) demonstrated a statistically significant correlation with disease response to therapy on PET/CT. Fifteen of 20 papers (75%) demonstrated an independent statistically significant correlation with clinical outcomes. In the CAYAHL population, volumetric PET parameters are valuable for risk stratification despite heterogeneity in results. Future harmonization of the segmentation approach will facilitate incorporation of MTV into clinical practice.

PURPOSE Doxorubicin, bleomycin, vinblastine, and dacarbazine (ABVD) chemotherapy is used commonly for pediatric Hodgkin lymphoma (pHL) in low- and middle-income countries. The role of radiotherapy (RT) after ABVD in pHL is uncertain. MATERIALS AND METHODS We conducted a systematic review to explore the use of ABVD with or without RT in pHL. Key clinical questions included the number of cycles of ABVD, indications for and dose of RT, and outcomes by risk group. A search was performed in PubMed. Articles reporting survival outcomes by risk group were included. RESULTS Of 97 articles identified in the literature search, nine met inclusion criteria. Chemotherapy consisted of four to six cycles in limited disease and mostly six cycles in advanced disease. Three studies used RT for all patients within a specified risk group. Six studies dictated an adapted RT approach, with 3%-43% of the patients receiving RT for bulky adenopathy, slow early response (SER), and/or incomplete response. Radiation doses ranged between 20 and 36 Gy. The progression-free survival and overall survival at 4-10 years ranged from 84% to 100% and 93%-100% in limited disease and 50%-84.4% and 75%-95.3% in advanced disease, respectively. Studies did not directly assess the impact of certain chemotherapy or RT strategies. Recommendations were made after reviewing outcomes with particular approaches. CONCLUSION Four cycles of ABVD are recommended for limited disease, and six cycles of ABVD are recommended for advanced disease. In both limited and advanced diseases, RT is recommended with a dose of 20-21 Gy only to sites of bulky and/or SER, with a boost of up to 36 Gy to sites of incomplete response. This approach could spare radiation for at least half of the patients with limited disease and one third of advanced disease.