The presence of a bulky mediastinal mass of 7 cm or greater in diameter confers an adverse prognosis to patients with advanced Hodgkin lymphoma in case of negative interim PET/CT.

In the PET-adapted therapy era, a bulky mediastinal mass (BMM) is not considered a risk factor in patients with advanced-stage Hodgkin lymphoma (HL). The current retrospective study aimed to estimate the prognostic significance of BMM presence and size for disease-free survival (DFS) and determine the most accurate mass size cutoff (among 5 cm, 7 cm, 10 cm) to predict inferior DFS in such patients. The study included 196 advanced-HL patients treated at Rambam (n = 121) and Memorial Sloan Kettering Cancer Center (n = 75) between 2002 and 2016. At a median follow-up of 66.5 (1-222) months, 36 relapses occurred. In multivariate analysis, only the cutoff of 7 cm predicted inferior DFS and PFS (p < 0.007 and <0.038, respectively) in interim PET/CT (PET-2) negative (79%) patients. This study identifies the BMM size cutoff of 7 cm in any plane as most precise in predicting adverse prognosis in PET-2-negative patients with advanced-stage HL. More aggressive initial chemotherapy than ABVD improves such prognosis.