Rhythm alteration in patients with metastatic breast cancer and poor prognostic factors

Circulating blood cell counts, serum cortisol, proteins, alkaline phosphatase, carcinoembryonic antigen and CA15.3 displayed significant circadian rhythms in a group of 13 women with metastatic breast cancer. Statistical significance (P < 0.05) was assessed with both analysis of variance and cosinor analysis. All patients had been previously treated with chemo-and/or radiotherapy and/or antiestrogens. All patients had been treatment-free for 1 month prior to the study. Each patient had blood drawn every 4 h for 48 h. Circadian rhythms were examined as a function of performance status, graded according to the World Health Organization, liver involvement and number of metastatic sites. Group circadian rhythms in serum cortisol or proteins were abolished in patients with liver metastases, and were altered in cases of poor performance status. Circulating leukocytes, neutrophils or platelets did not exhibit synchronized circadian rhythmicity in patients with poor performance status or liver metastases. The number of metastatic organs had a minor influence on circadian rhythmicity. These results suggest that rhythm alteration may be associated with both poor performance status and liver metastases in patients with advanced breast cancer. Such alteration of the normal circadian time structure may favor and/or result from cancer spread.