title: A viscerally driven cachexia syndrome in patients with advanced colorectal cancer: contributions of organ and tumor mass to whole-body energy demands.
abstract: BACKGROUND
  Cancer cachexia-associated weight loss is poorly understood; energetically demanding tissues (eg, organ and tumor mass) and resting energy expenditure (REE) are reported to increase with advanced cancer.
  
  
  OBJECTIVE
  The objective was to quantify the potential contribution of increasing masses of energetically demanding tissues to REE with colorectal cancer cachexia progression.
  
  
  METHODS
  A longitudinal computed tomography (CT) image review was performed to quantify organ size (liver, including metastases, and spleen) and peripheral tissues (skeletal muscle and adipose tissue) during colorectal cancer cachexia progression (n = 34). Body composition was prospectively evaluated by CT and dual-energy X-ray absorptiometry, and REE was determined by indirect calorimetry in advanced colorectal cancer patients (n = 18).
  
  
  RESULTS
  Eleven months from death, the liver (2.3 +/- 0.7 kg) and spleen (0.32 +/- 0.2 kg) were larger than reference values. One month from death, liver weight increased to 3.0 +/- 1.5 kg (P = 0.010), spleen showed a trend to increase (P = 0.077), and concurrent losses of muscle (4.2 kg) and fat (3.5 kg) (P < 0.05) were observed. The estimated percentage of fat-free mass (FFM) occupied by the liver increased from 4.5% to 7.0% (P < 0.001). The most rapid loss of peripheral tissues and liver and metastases gain occurred within 3 mo of death. A positive linear relation existed between liver mass and measured whole-body REE (r(2) = 0.35, P = 0.010); because liver accounted for a larger percentage of FFM, measured REE . kg FFM(-1) . d(-1) increased (r(2) = 0.35, P = 0.010).
  
  
  CONCLUSIONS
  Increases in mass and in the proportion of high metabolic rate tissues, including liver and tumor, represented a cumulative incremental REE of approximately 17,700 kcal during the last 3 mo of life and may contribute substantially to cachexia-associated weight loss.
authors.affiliation: Department of Oncology, University of Alberta, Edmonton, Alberta, Canada.
authors.forename: Jessica R
authors.initials: JR
authors.lastname: Lieffers
authors.forename: Marina
authors.initials: M
authors.lastname: Mourtzakis
authors.forename: Kevin D
authors.initials: KD
authors.lastname: Hall
authors.forename: Linda J
authors.initials: LJ
authors.lastname: McCargar
authors.forename: Carla M M
authors.initials: CM
authors.lastname: Prado
authors.forename: Vickie E
authors.initials: VE
authors.lastname: Baracos
mesh_terms: D015502:Absorptiometry, Photon; D000273:Adipose Tissue / Q000378:metabolism; D001481:Basal Metabolism / Q000502:physiology*; D001823:Body Composition / Q000502:physiology; D002100:Cachexia / Q000209:etiology / Q000378:metabolism*; D002153:Calorimetry, Indirect; D015331:Cohort Studies; D015179:Colorectal Neoplasms / Q000378:metabolism*; D018450:Disease Progression; D005260:Female; D006801:Humans; D008099:Liver / Q000378:metabolism* / Q000473:pathology; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000378:metabolism; D009362:Neoplasm Metastasis; D009929:Organ Size / Q000502:physiology*; D011446:Prospective Studies; D012189:Retrospective Studies; D013154:Spleen / Q000378:metabolism / Q000473:pathology; D014057:Tomography, X-Ray Computed; D015431:Weight Loss / Q000502:physiology