Even in the earliest days following a diagnosis of breast cancer, maladaptive coping styles are associated with a disruption in circadian rhythms – which are proven in metastatic disease to be a prognostic indicator of mortality.
The surprising finding, reported in the journal Annals of Behavioral Medicine (2012;44:10-20), holds potentially profound implications for the timing and tailoring of psychological interventions in newly diagnosed patients.
"Given that circadian cycles regulate tumor growth, we need greater understanding of possible psychosocial effects in cancer-related circadian disruption," concluded the study’s authors, led by Dr. Eric Dedert of Duke University Medical Center and the Veterans Affairs Medical Center in Durham, N.C.
The fact that circadian disruption was significant in a subset of patients a mean 19 days after diagnosis suggests that there may be no time to waste in identifying and treating potentially maladaptive coping responses that could impact not only their adjustment, but also their prognosis.
The study followed 57 women (mean age, 52 years) scheduled for breast cancer surgery, 54 of whom had just received a primary diagnosis and 3 who were facing surgery for recurrent disease. Psychological coping was measured in these patients, along with salivary cortisol and rest/activity circadian rhythms for 4 days.
Those with intrusive thoughts related to their diagnosis and avoidant coping styles (denial, self-distraction, and behavioral disengagement) were statistically more likely to demonstrate uneven rest/activity circadian rhythms and daytime sedentariness.
"In this newly diagnosed sample, intrusion-related inactivity during the daytime might be an indication that patients were seeking emotional numbness by disengaging from their environments and remaining sedentary," the authors noted.
"As indicated in the avoidance literature, this disengagement has the paradoxical effect of increasing distress."
The study has limitations, of course: a small sample size, a cross-sectional design, and the possibility that patients inclined to enroll might represent a biased sample in terms of coping styles. Of note, however, was the authors’ anecdotal report that some who refused to participate appeared to be "feeling overwhelmed with diagnosis and surgery planning," suggesting that the study may have underestimated the early impact of coping style on circadian rhythms.
The authors offered a comprehensive overview of a growing literature documenting intriguing (and ominous) associations among circadian rhythm disruption and physical, emotional, and social functioning in cancer patients, as well as tumor progression and mortality.
It’s a complex web that obviously needs much more elaboration before cause-and-effect conclusions might be drawn, but for now, the findings in early breast cancer patients certainly warrant paying close attention to coping from Day 1.
The study was funded by the University of Louisville (Ky.) Intramural Research Incentive Grant for Research on Women. The investigators reported no conflicts of interest.
Dr. Freed is a psychologist in Santa Barbara, Calif., and a medical journalist.