ASH Clinical News FINAL_ACN_3.14_FULL_ISSUE_DIGITAL | Page 54

Written in Blood Study Identifies Two Measures of Tumor Burden for Risk Stratification of Patients With Hodgkin Lymphoma The presence of bulky disease is commonly used as one factor in categorizing patients with early-stage Hodgkin lymphoma (HL) as having either favorable or unfavorable risk, as well as to determine whether patients can safely de-escalate therapy without com- promising disease control. However, because definitions of bulky disease vary, re- searchers have hypothesized that other, three-dimensional measurements could improve risk stratification and the quantification of disease burden. Mani Akhtari, MD, of the Department of Radiation Oncology at the University of Texas Medical Branch Hospitals, and co-authors assessed whether two measures of tumor volume on F-fluorodeoxyglucose positron emission tomography/ computed tomography (PET/CT) – specifically metabolic tumor volume (MTV; total volumetric sum of all areas of disease) and total lesion glycolysis (TLG; volumetric sum adjusted for standardized uptake value) – could reliably stratify risk among patients with early-stage HL. According to results published in Blood, MTV and TLG predicted which patients with early-stage HL would have worse outcomes. “Most importantly, we have shown that not all patients with early-stage, unfavor- able HL are the same,” the authors noted. “In fact, two distinct categories can be discerned by the MTV or TLG, into low and high disease burdens.” The investigators retrospectively reviewed the records of all adult pa- tients diagnosed with HL who were treated at the University of Texas MD Anderson Cancer Center in Houston between January 2003 and Decem- ber 2013. Disease was delineated on pre-chemotherapy PET/CT scans by two methods: manual contouring and sub-thresholding of these con- tours. Sub-thresholding determined tumor volume with standard uptake volume ≥2.5. MTV; TLG measures were extracted from the threshold volumes (MTV t , TLG t ), as well as from the manually contoured soft-tissue volumes (MTV st , TLG st ). They identified 267 patients (median age = 32 years; range = 18-95 years) with Ann Arbor stage I or II dis- ease and a combined initial PET/CT scan (separate PET and CT images merged into a single image). Patients with all histologic HL subtypes were included, except those with nodular lympho- cyte-predominant HL. Patients were excluded if they had a follow-up of six months or less, unless they experienced disease progression or death. For this study, the researchers 52 ASH Clinical News defined bulky disease as any nodal mass or conglomerate greater than 10 cm in the axial, sagittal, or coronal dimensions. Patients were classified with either unfavor- able (n=178; 16%), favorable (n=74; 28%), or stage IIB-advanced (n=15; 6%) disease. Most (n=224; 84%) had stage II disease. The most common treatment regimen patients received was ABVD (doxorubi- cin, bleomycin, vinblastine, dacarbazine; n=239; 89%), and 250 patients experienced a complete response following chemotherapy. Three-quarters of patients (n=187) went on to receive consolidative radiation therapy at a median dose of 30.6 Gy (range =