Prevalence, pattern and prognosis of lung lesions in pediatric Hodgkin lymphoma.

Children and adolescents with classical Hodgkin lymphoma have a progression-free survival (PFS) rate of ≥ 90% with current treatments. The current challenge is to reduce adverse late-effects while maintaining high survival. Distinguishing lung involvement (Stage IV) from benign lung lesions remains a staging challenge in pediatric Hodgkin lymphoma (pHL). This study analyzed the prevalence, morphological patterns, and prognostic impact of lung lesions on progression-free survival (PFS) within the EuroNet-PHL-C1 trial. A retrospective analysis was conducted on chest CT scans from 1,298 pHL patients enrolled in the EuroNet-PHL-C1 trial. Patients were stratified by established treatment groups (TG-1, TG-2, TG-3). Lesions were classified by morphological pattern, and Kaplan-Meier analysis was used to compare 60-month PFS between groups with and without lung lesions. Lung lesions were identified in 60.2% (782/1298) of patients, with nodules being the predominant pattern (89%). In the combined TG-1 and TG-2 cohort (early/intermediate stages), the presence of any lung lesion correlated with significantly lower 5-year PFS (85.5% vs. 91.7%; p = 0.0197). Importantly, this lower PFS was driven by non-nodule morphologies. In the TG-3 (advanced stage) cohort, neither the presence of lung lesions nor stage IV classification significantly affected PFS. Lung lesions are highly prevalent in pHL. However, the presence of pulmonary nodules does not confer an inferior prognosis. The prognostic impact of lung lesions is primarily limited to non-nodule patterns in early-stage disease. These findings suggest that incorporating morphological patterns may be beneficial for refining risk stratification in future pHL trials.