Persistent mediastinal FDG uptake on PET-CT after frontline therapy for Hodgkin lymphoma: biopsy, treat or observe?

Residual mediastinal FDG-uptake after frontline therapy for classical Hodgkin lymphoma (cHL) may constitute persistent disease or inflammatory changes. We analyzed practice patterns at two institutions to determine how often a mediastinal biopsy influenced patient management and outcome. Forty-two cases were eligible for review, mostly treated with ABVD. Twenty (group1) underwent a mediastinal biopsy and 22 did not (group2). In group1, 10/20 were positive for cHL and proceeded to salvage therapy (ST); 4/10 biopsy-negative patients were observed, and 6/10 received consolidative radiotherapy. Ten of 22 patients from group 2 were observed, 12/22 received ST. Ten of 14 observed patients remained PET-positive and 8/8 biopsies in these patients showed cHL. Deauville score (DS) 5 was associated with a positive biopsy (10/16). No overall survival difference between groups was observed. We conclude that observation and repeat a FDG-PET is reasonable for DS3-4 while for DS5, ST should be considered pending biopsy confirmation when feasible.