title: Diminished quality of life in patients with cancer correlates with tryptophan degradation.
abstract: OBJECTIVE
  Quality of life (QoL) is frequently impaired in patients suffering from malignant disease. Disturbed metabolism of neurotransmitter serotonin might be crucially involved, and serotonin-precursor tryptophan is degraded during pro-inflammatory immune response. In this study, we compared QoL and fatigue self-rating scores of patients with various types of malignancy with tryptophan metabolic changes and immune activation status.
  
  
  METHODS
  Venous blood was collected from 146 patients with gastrointestinal tumors (n = 43), hematological malignancy (n = 40), gynecological neoplasms (n = 26), lung cancer (n = 20) and from tumors of other localization (n = 17).
  
  
  RESULTS
  QoL was significantly reduced in patients suffering from progressive tumor disease in comparison to stable or remitting disease, also feeling of fatigue was increased (both P < 0.001). Serum tryptophan concentrations were lower in patients with progressive disease (P < 0.01), and decreased tryptophan concentrations were related to decreased QoL (r(s) = 0.256, P < 0.01) and increased fatigue (r(s) = -0.179; P < 0.05). Concentrations of tryptophan and kynurenine and the kynurenine to tryptophan ratio were predictive for impaired QoL and increased fatigue in univariate regression analysis, in multivariate analysis higher ESR and neopterin concentration in combination with stage of disease predicted QoL deterioration.
  
  
  CONCLUSIONS
  Results suggest that immune-mediated tryptophan degradation may contribute to cancer-induced QoL deterioration.
authors.affiliation: Division of Biological Chemistry, Biocenter, Innsbruck Medical University, Fritz Pregl Strasse 3, 6020 Innsbruck, Austria.
authors.forename: Katharina
authors.initials: K
authors.lastname: Schroecksnadel
authors.forename: Michael
authors.initials: M
authors.lastname: Fiegl
authors.forename: Karin
authors.initials: K
authors.lastname: Prassl
authors.forename: Christiana
authors.initials: C
authors.lastname: Winkler
authors.forename: Hubert A
authors.initials: HA
authors.lastname: Denz
authors.forename: Dietmar
authors.initials: D
authors.lastname: Fuchs
mesh_terms: D000368:Aged; D018450:Disease Progression; D005221:Fatigue / Q000209:etiology; D005260:Female; D006801:Humans; D007111:Immunity, Cellular; D017567:Karnofsky Performance Status; D007737:Kynurenine / Q000032:analysis; D008297:Male; D008875:Middle Aged; D009369:Neoplasms / Q000378:metabolism* / Q000523:psychology*; D019798:Neopterin / Q000032:analysis; D011379:Prognosis; D011788:Quality of Life; D016019:Survival Analysis; D014364:Tryptophan / Q000378:metabolism*
chemical_list: D007737:Kynurenine; D019798:Neopterin; D014364:Tryptophan