title: Cortisol diurnal variation in blood and saliva of patients with metastatic colorectal cancer: relevance for clinical outcome.
abstract: BACKGROUND
  In healthy humans, cortisol displays marked 24-hour rhythms in serum and saliva, with a strong correlation between both fluids; the circadian variation of salivary cortisol is prognostic of longer survival in patients with metastatic breast cancer. In order to confirm these results in a non-hormone-dependent cancer, cortisol concentrations in serum and saliva were compared at different circadian stages, in patients with metastatic colorectal cancer.
  
  
  METHODS
  A first study consisted of round-the-clock sampling for two 24-hour periods, in 18 patients. A second study consisted of blood and salivary sampling at 8:00h and 16:00h, on 2 consecutive days, in 192 patients.
  
  
  RESULTS
  Group circadian variations were validated in both body fluids. Cortisol concentrations in the serum and in saliva were significantly correlated in only 62% of the 18 patients in the first study. In the second study, the average cortisol concentrations were higher at 8:00h than at 16:00h, in serum as well as in saliva. Measures from both body fluids were correlated in patients with a marked 24-hour rhythm, but plasma and salivary cortisol did not correlate in patients with a damped diurnal variation. The patient's performance status and extent of liver involvement, as well as the patient's rest activity cycle were influential on cortisol average concentration, but not on its circadian variation. The circadian variation in cortisol was prognostic of neither response, nor survival.
  
  
  CONCLUSIONS
  These results indicate that the assessment of salivary cortisol cannot substitute for that of serum cortisol in metastatic colorectal cancer. This study suggests that the clinical relevance of cortisol circadian rhythm for patient outcome may differ according to the hormonal dependency of the tumor.
authors.affiliation: INSERM EPI 0118 Chronothérapeutique des cancers and Chronotherapy Unit, Federation des Maladies Sanguines et Tumorales, Villejuif, France.
authors.forename: Marie-Christine
authors.initials: MC
authors.lastname: Mormon
authors.forename: André
authors.initials: A
authors.lastname: Bogdan
authors.forename: Sylvie
authors.initials: S
authors.lastname: Cormont
authors.forename: Yvan
authors.initials: Y
authors.lastname: Touitou
authors.forename: Francis
authors.initials: F
authors.lastname: Lévi
mesh_terms: D000328:Adult; D000368:Aged; D000704:Analysis of Variance; D002940:Circadian Rhythm / Q000502:physiology*; D015179:Colorectal Neoplasms / Q000097:blood / Q000378:metabolism* / Q000473:pathology; D005260:Female; D006801:Humans; D006854:Hydrocortisone / Q000097:blood / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D009362:Neoplasm Metastasis; D011379:Prognosis; D012463:Saliva / Q000378:metabolism*
chemical_list: D006854:Hydrocortisone