title: Diurnal cortisol rhythm as a predictor of lung cancer survival.
abstract: BACKGROUND
  Poorly coordinated diurnal cortisol and circadian rest-activity rhythms predict earlier mortality in metastatic breast and colorectal cancer, respectively. We examined the prognostic value of the diurnal cortisol rhythm in lung cancer.
  
  
  METHODS
  Lung cancer patients (n=62, 34 female) were within 5 years of diagnosis and had primarily non small-cell lung cancer, with disease stage ranging from early to advanced. Saliva collected over two days allowed calculation of the diurnal cortisol slope and the cortisol awakening response (CAR). Lymphocyte numbers and subsets were measured by flow cytometry. Survival data were obtained for 57 patients. Cox Proportional Hazards analyses were used to test the prognostic value of the diurnal cortisol rhythm on survival calculated both from study entry and from initial diagnosis.
  
  
  RESULTS
  The diurnal cortisol slope predicted subsequent survival over three years. Early mortality occurred among patients with higher slopes, or relatively "flat" rhythms indicating lack of normal diurnal variation (Cox Proportional Hazards p=.009). Cortisol slope also predicted survival time from initial diagnosis (p=.012). Flattened profiles were linked with male gender (t=2.04, df=59, p=.046) and low total and cytotoxic T cell lymphocyte counts (r=-.39 and -.30, p=.004 and .035, respectively). After adjustment for possible confounding factors, diurnal slope remained a significant, independent predictor of survival.
  
  
  CONCLUSIONS
  Flattening of the diurnal cortisol rhythm predicts early lung cancer death. Data contribute to growing evidence that circadian disruption accelerates tumor progression.
authors.affiliation: Department of Psychological and Brain Sciences, University of Louisville, Louisville, KY 40292-0001, USA. sephton@louisville.edu
authors.forename: Sandra E
authors.initials: SE
authors.lastname: Sephton
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Lush
authors.forename: Eric A
authors.initials: EA
authors.lastname: Dedert
authors.forename: Andrea R
authors.initials: AR
authors.lastname: Floyd
authors.forename: Whitney N
authors.initials: WN
authors.lastname: Rebholz
authors.forename: Firdaus S
authors.initials: FS
authors.lastname: Dhabhar
authors.forename: David
authors.initials: D
authors.lastname: Spiegel
authors.forename: Paul
authors.initials: P
authors.lastname: Salmon
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002289:Carcinoma, Non-Small-Cell Lung / Q000378:metabolism / Q000401:mortality* / Q000523:psychology; D002940:Circadian Rhythm / Q000502:physiology*; D003863:Depression / Q000378:metabolism / Q000523:psychology; D005221:Fatigue / Q000378:metabolism / Q000523:psychology; D005260:Female; D006801:Humans; D006854:Hydrocortisone / Q000032:analysis* / Q000378:metabolism; D008175:Lung Neoplasms / Q000378:metabolism / Q000401:mortality* / Q000523:psychology; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011379:Prognosis; D012463:Saliva / Q000737:chemistry / Q000378:metabolism; D012890:Sleep / Q000502:physiology; D011795:Surveys and Questionnaires
chemical_list: D006854:Hydrocortisone