Reclassifying patients with early-stage Hodgkin lymphoma based on functional radiographic markers at presentation

The presence of bulky disease in Hodgkin lymphoma (HL), traditionally defined with a 1-dimensional measurement, can change a patient9s risk grouping and thus the treatment approach. We hypothesized that 3-dimensional measurements of disease burden obtained from baseline 18 F-fluorodeoxyglucose positron emission tomography-computed tomography (PET-CT) scans, such as metabolic tumor volume (MTV) and total lesion glycolysis (TLG), would more accurately risk stratify patients. To test this hypothesis, we reviewed pretreatment PET-CT scans of patients with stage I-II HL treated at our institution between 2003–2013. Disease was delineated on pre-chemotherapy PET-CT scans by two methods: 1) manual contouring, and 2) sub-thresholding of these contours to give the tumor volume with SUV≥2.5. MTV and TLG were extracted from the threshold volumes (MTV t , TLG t ), as well as from the manually contoured soft-tissue volumes (MTV st , TLG st ). At a median follow-up time of 4.96 years for the 267 patients evaluated, 27 patients were diagnosed with relapsed or refractory disease and 12 patients died. Both MTV t and TLG t were highly correlated with freedom from progression (FFP) and were dichotomized with 80th percentile cut-off values of 268 and 1703, respectively. Consideration of MTV and TLG enabled re-stratification of early-unfavorable HL patients as having low-risk and high-risk disease. We conclude that MTV and TLG provide a potential measure of tumor burden to aid in risk stratification of early unfavorable HL patients.