Circadian Disruption and Prostate Cancer Risk: An Updated Review of Epidemiological Evidences

Since the publication of the International Agency for Research on Cancer Monograph in 2007 classifying night shift work leading to a disruption of circadian rhythm as probably carcinogenic to humans, there is an increasingly growing interest in understanding how circadian disruption may play a role in cancer development. This systematic review provides a comprehensive update on epidemiologic evidences on circadian disruption and prostate cancer since the last review published in 2012. We identified 12 new studies evaluating the effects of several circadian disruptors such as night shift work, sleep patterns, and circadian genes in prostate cancer risk. In contrast, no new studies have focused on exposure to light at night. Several convincing and biologically plausible hypotheses have been proposed to understand how circadian disruption may be related to cancer. However, the current difficulty of concluding on the role of circadian disruption on prostate cancer risk requires further studies including a better characterization of the different night shift systems, data on sleep patterns and chronotype, measurement of biomarkers, and investigations of polymorphisms in the genes regulating the biological clock. (C) 2017 AACR.