Behrang Amini1, Yves-Paul N Nakache2, Lorenzo Nardo2, Elisabet E Manasanch3, Jia Sun4, Leon Lenchik5, Robert D Boutin6. 1. Department of Musculoskeletal Imaging, The University of Texas, MD Anderson Cancer Center, 1515 Holcombe Blvd, Unit 1475, Houston, TX, 77030, USA. bamini@mdanderson.org. 2. Department of Radiology, The University of California, Davis, Davis, CA, USA. 3. Department of Lymphoma/Myeloma, The University of Texas, M.D. Anderson Cancer Center, Houston, TX, USA. 4. Department of Biostatistics, The University of Texas, M.D. Anderson Cancer Center, Houston, TX, USA. 5. Department of Diagnostic Radiology, Wake Forest School of Medicine, Winston-Salem, NC, USA. 6. Department of Diagnostic Radiology, Stanford University, Stanford, CA, USA.
Abstract
OBJECTIVE: To determine association of body composition measurements on CT and PET with progression of smoldering myeloma to multiple myeloma. METHODS: A retrospective cohort study in 65 patients with smoldering myeloma and PET/CT at diagnosis was performed at a tertiary cancer center. Subjects were between 38 and 87 years of age (mean 64) and included 37 males. Primary outcome was progression-free survival as a function of bone, fat, and muscle metrics on CT and PET (measured at the level of L4 pedicles) and clinical confounders. CT metrics included attenuation of L4 and retroperitoneal fat and various indices derived from the psoas muscle. PET measures included SUVmax and SUVmean of L4, retroperitoneal fat, and psoas. Cox proportional hazards modeling was performed with entry and retention criteria of p < 0.1 and p < 0.05, respectively. RESULTS: SUVmax and SUVmean were associated for each compartment (R2 = 0.78-0.84), and SUVmean (SUV) was used for subsequent analyses. SUV of the L4 vertebral body was associated with attenuation of the L4 vertebral body (p = 0.0032). There was no association between SUV and CT for muscle and fat compartments. In the subset of patients with bone marrow biopsy results (n = 43), there was no association between SUV of L4 and plasma cell concentration on core biopsy or flow cytometry (p = 0.089 and 0.072, respectively). The final Cox model showed association with albumin (HR 0.29, 95%CI 0.088-0.93, p = 0.038), M protein (HR 1.31, 95%CI 1.021-1.68, p = 0.034), and SUV of L4 (HR 1.99, 95%CI 1.037-3.82, p = 0.039). CONCLUSION: SUV of L4 is a prognostic indicator in patients with smoldering myeloma.
OBJECTIVE: To determine association of body composition measurements on CT and PET with progression of smoldering myeloma to multiple myeloma. METHODS: A retrospective cohort study in 65 patients with smoldering myeloma and PET/CT at diagnosis was performed at a tertiary cancer center. Subjects were between 38 and 87 years of age (mean 64) and included 37 males. Primary outcome was progression-free survival as a function of bone, fat, and muscle metrics on CT and PET (measured at the level of L4 pedicles) and clinical confounders. CT metrics included attenuation of L4 and retroperitoneal fat and various indices derived from the psoas muscle. PET measures included SUVmax and SUVmean of L4, retroperitoneal fat, and psoas. Cox proportional hazards modeling was performed with entry and retention criteria of p < 0.1 and p < 0.05, respectively. RESULTS: SUVmax and SUVmean were associated for each compartment (R2 = 0.78-0.84), and SUVmean (SUV) was used for subsequent analyses. SUV of the L4 vertebral body was associated with attenuation of the L4 vertebral body (p = 0.0032). There was no association between SUV and CT for muscle and fat compartments. In the subset of patients with bone marrow biopsy results (n = 43), there was no association between SUV of L4 and plasma cell concentration on core biopsy or flow cytometry (p = 0.089 and 0.072, respectively). The final Cox model showed association with albumin (HR 0.29, 95%CI 0.088-0.93, p = 0.038), M protein (HR 1.31, 95%CI 1.021-1.68, p = 0.034), and SUV of L4 (HR 1.99, 95%CI 1.037-3.82, p = 0.039). CONCLUSION: SUV of L4 is a prognostic indicator in patients with smoldering myeloma.