[Dynamic circadian system patients under chimiotherapy]

Currently, the circadian timing system of cancer patients can be estimated with wrist actimetry, which provides numerical data on the continuous activity of patients. The method of processing of these data, which we implemented, aims at answering the following questions: is the circadian timing system stable before chemotherapy, is this system extensively modified by chemotherapy, are there structural modifications or a decrease in activity amplitude produced by chemotherapy and how does the circadian activity rhythm recover? Here, we determine a circadian model function using a wavelet transform prior to chemotherapy delivery. Then we measure the correlation between this model function and the evolution of the circadian rhythm of activity over the whole observation span during and after chemotherapy. The application of this method to the record of activity rhythms in cancer patients highlights the characteristics and the recovery pattern of chemotherapy-induced alterations of the circadian timing system.