Relationships of salivary cortisol and melatonin rhythms to sleep quality, emotion, and fatigue levels in patients with newly diagnosed lung cancer

Purpose: After being diagnosed with lung cancer, patients often experience sleep disturbance, anxiety, depression, and fatigue. These symptoms may occur because of changes in neurotransmitter secretion caused by tumors. This study investigated the correlation of cortisol and melatonin rhythms with sleep quality, anxiety, depression, and fatigue levels in patients with newly diagnosed lung cancer. Method: We conducted a case control study and recruited 40 patients with newly diagnosed lung cancer and 40 healthy adults. Results: The patient group had a lower salivary melatonin level and flatter slope (p < 0.001 and p < 0.001), higher salivary cortisol level and steeper slope (p < 0.001 and p < 0.001), higher sleep disturbance level (p = 0.004), and higher depression level (p < 0.001). The multivariate linear regression analysis indicated that the cortisol slope (p = 0.005) and fatigue score (p = 0.032) predicted the sleep quality score (p = 0.011). Conclusion: Overall, the patients with newly diagnosed lung cancer had poorer sleep quality, higher depression levels, lower salivary melatonin levels, higher cortisol levels, and flatter melatonin and cortisol slopes than did the controls. The fatigue level and cortisol slope significantly predicted sleep quality. Therefore, the assessment of cortisol and melatonin rhythms and levels could provide crucial information that may be beneficial for managing symptoms in patients with newly diagnosed lung cancer. (C) 2017 Elsevier Ltd. All rights reserved.