Abstract P101

Towards Incorporation of Pediatric Specific Criteria in the Revised Lugano Classification of Hodgkin Lymphoma (HL) Staging and Response: Report from the ICML Pediatric Subcommittee

Purpose: The Lugano Classification is the benchmark for evaluation of nodal lymphomas yet pediatric (ped) specific recommendations have not been included limiting its application to children. With increasing collaboration for AYA lymphoma clinical trials, inclusion of ped criteria is essential to allow for use of the Lugano Classification to all patients. With planned major updates to the 2014 classification, an opportunity to consider ped specific issues was identified.

Methods: 6 representatives from North America & Europe, HL & NHL, pediatric & radiation oncology & nuclear medicine convened to develop ped specific revisions. Ped-specific biomarker expertise was also obtained.

Results: The Ped Subcommittee (11 meetings between 9/2022-4/2023) recommended: Initial Evaluation: Systematic assessment of cancer predisposition risk and referral to genetic counseling; Consider risk for underlying immunodeficiency in select cases. Staging Criteria–Imaging: Limit lifetime exposures to radiation and anesthesia; Use measures to reduce brown fat activation to minimize PET false-positive results; reactive nodes<2 cm due to infection/inflammation are more common in children; Specific size criteria may underestimate bulk or organomegaly in children. Staging Criteria–Biomarkers: Few validated for clinical practice; TME by nanostring, image mass cytometry, ctDNA, TARC, MTV are of research interest. Prognostic Groups & Treatment Allocation: Risk stratification criteria vary from adult and across ped HL regimens. Most utilize low, intermediate and high-risk groups: E, bulk, & ESR/CRP elevations are used for treatment allocation regardless of stage; Age, leukocyte count, hematocrit, lymphocyte count, albumin, & number of nodal sites are not routinely used. Assessment of Response During Treatment: New PET avid nodes should not be considered a new site of disease if original sites had adequate response, especially if history or other findings suggest infection/inflammation. Follow Up Evaluations: False-positive findings may be related to thymic rebound or inflammation/infection; Ongoing imaging in the absence of clinical symptoms >2 years after treatment is not recommended; MRI or ultrasound are prioritized to limit lifetime radiation exposure; Lifelong follow up to monitor for late toxicities is highly encouraged.

Conclusion: Inclusion of ped specific criteria for staging & response criteria is essential and will expedite advances in ped & adult lymphoma together.