NON-INVASIVE ESTIMATION OF THE CIRCADIAN RHYTHM IN SERUM CORTISOL IN PATIENTS WITH OVARIAN OR COLORECTAL CANCER Marie-Christine MORMONT 1 , Bernard HECQUET 2 , Andre ´BOGDAN 3 , Manuel BENAVIDES 1 , Yvan T OUITOU 3 and Francis LE ´ VI 1 * 1 Laboratoire ‘‘Rythmes Biologiques et Chronothe ´rapeutique’’, Universite ´ Paris XI and ICIG, Ho ˆpital Paul Brousse, Villejuif, France 2 Centre Oscar Lambret, Lille, France 3 De ´partement de Biochimie Me ´dicale, Ho ˆ pital de la Pitie ´-Salpe ˆtrie `re, Paris, France The variability in toxicity or efficacy of cancer chrono- therapy among patients may be due to differences in circa- dian rhythm. Adequate assessment of circadian rhythm often requiresrepeated blood sampling over at least a 24-hr period; this cannot be a routine procedure. W e attempted to assess the reliability of a 2-timepoint estimate of the 24-hr rhythm of serum cortisol in 19 healthy subjects, 19 women with ovarian cancer and 18 patients with metastatic colorectal cancer. T he difference between daily maximum and minimum values (MAX–MIN) was compared with that observed between values at 08.00 and at 16.00 (H8–H16). As significant correla- tions were found between both variables in all groups, we conclude that the magnitude of circadian changes in serum cortisol may be estimated from blood samples collected at 08.00 and at 16.00. T he clinical relevance and the prognostic value of this method of assessment are currently under evaluation in a larger-scale clinical trial. Int. J. Cancer 78:421–424, 1998.  1998 Wiley-Liss, Inc. The therapeutic index of more than 30 anticancer agents can be modified by varying the time of drug administration (reviewed in Le ´vi, 1997). Specifically timed chemotherapy (chronotherapy) has been applied successfully to patients with advanced ovarian cancer, in 2 limited-scale trials (Hrushesky, 1985; Le ´vi et al., 1990), and has been confirmed as an effective treatment against metastatic colorectal cancer in more than 1,000 patients (Le ´vi, 1996; Le ´vi et al., 1997). Results from phase I, II and III trials have demonstrated that chronomodulated delivery of 5-fluorouracil, folinic acid and oxaliplatin could simultaneously reduce up to 5-fold the incidence of severe toxic effects and almost double antitumor efficacy (Le ´vi, 1996; Le ´vi et al., 1997). In these trials, however, interpatient variability, both in efficacy and toxicity, was observed, indicating that factors other than the clock-hour of treatment influenced outcome. Malignant tumors and cancer-bearing hosts may exhibit nearly normal or markedly altered circadian rhythms, as documented by both experimental and clinical data. Rhythm alterations in healthy organs as well as in tumors depend upon tumor type, growth rate and level of differentiation. These alterations consist of amplitude damping, phase shifts and/or appearance of ultradian (short-term) rhythms; they usually become more prominent at late stages of cancer development (reviewed in Mormont and Le ´vi, 1997). In patients with advanced ovarian or metastatic breast cancer, group circadian rhythms were documented for cortisol, leukocyte and neutrophil counts. Nonetheless, at the individual level, circa- dian rhythmicity was markedly altered in patients with poor World Health Organization (WHO, 1979) performance status (PS), large residual tumor size or liver metastases. In 13 women with advanced breast cancer, cortisol rhythm alterations were associated with poor PS and with liver metastases (Touitou et al., 1995, 1996). Similarly, the individual circadian rhythms of serum cortisol in 20 patients with advanced ovarian cancer were damped in the case of poor PS or large tumor burden (Benavides, 1991). Such an association between well-documented clinical prognostic factors and cortisol rhythmicity suggested that cortisol circadian rhythms could pro- vide a novel predictor for cancer patient outcome. In addition, chronotherapeutic regimens have been devised so that anticancer drugs are delivered, according to group schedules, at times of best average tolerability; differences in patients’ individual circadian rhythms could also contribute in part to interpatient variability in the toxicity and response to such chronochemotherapies. If so, cancer patients’ individual circadian rhythms would be worth exploring on a large-scale. Nevertheless, appropriate assessment of individual circadian rhythms demands repeated measurements, a procedure that cannot be implemented routinely. For instance, adequate measurement of cortisol rhythm would require blood sampling every 20 min over a 24-hr period (Van Cauter, 1989); this is not conceivable in a standard medical setting, with personnel unaware of, or not specialized in, chronobiology. We thus attempted to design a simple screening procedure that would provide an estimate of the cortisol 24-hr rhythm, based on 2 sampling times. Selected timepoints were 08.00, the time of peak cortisol secretion in healthy subjects (Touitou et al., 1982), and 16.00. Both times fit into the usual working hours of outpatient- clinic staff. The reliability of such a method was first analyzed retrospectively in 2 data bases collected earlier, involving healthy subjects and ovarian cancer patients, respectively; this assessment was then evaluated prospectively, in a clinical study in patients with metastatic colorectal cancer. MATERIAL AND METHODS Retrospective studies The first data base consisted of 76 series of 6 blood samples collected 4 hr apart from 19 healthy subjects: 7 young men, age (mean  SD) 24  3.9 years; 6 elderly women, age 74.7  10.4 years; and 6 elderly men, age 71.7  5.5 years. Four circadian time series were collected at 3-month intervals for each subject. The second data base included 19 time series (9–12 samples, 4 hr apart) from 19 hospitalized women with advanced ovarian cancer (Table I); all samples were collected prior to treatment. During the study, subjects in both groups had a regular social routine, with lights turned on at 07.00 (1 hr) and off at 22.00 (2 hr), and meals at fixed times, i.e., 08.15, 12.15 and 19.15 (30 min). Both data bases have been described (Touitou et al., 1982; Benavides, 1991). Prospective study The study was approved by the CCPPRB of Kremlin-Bice ˆtre (France). Eighteen patients with advanced metastatic colorectal cancer (Table II) were enrolled and gave written informed consent. A total of 34 time series, consisting of 5–6 blood samples, were collected during the first and last 24 hr of the first 4-day course of chronochemotherapy with 5-fluorouracil, folinic acid and oxalipla- tin (detailed treatment protocol given in Berthault-Cvitkovic et al., Grant sponsor: CNAMTS INSERM, Paris, France; Grant number: 3 AM 055; Grant sponsor: Re ´seau INSERM, Paris, France; Grant number: 4R007A; Grant sponsors: ARTBC Villejuif, France, and Compagnie de De ´veloppement Aquettant, Lyon, France. *Correspondence to: Laboratoire ‘‘Rythmes Biologiques et Chronothe ´ra- peutique’’, ICIG, Ho ˆpital Paul Brousse, 14-16, Avenue Paul Vaillant- Couturier, 94807 Villejuif Cedex, France. Fax: (33) 1-4559-3602. E-mail: flevi@hol.fr Received 18 March 1998; Revised 28 May 1998 Int. J. Cancer: 78, 421–424 (1998)  1998 Wiley-Liss, Inc. Publication of the International Union Against Cancer Publication de l’Union Internationale Contre le Cancer