Status and manifestations of sleep disorders and the status of drugs used to help fall sleep in Chinese breast cancer women at initial diagnosis and during chemotherapy

Purpose This study was designed to investigate the status and manifestations of sleep disorders and the status of drugs used to help fall sleep in Chinese breast cancer women at initial diagnosis and during chemotherapy. Patients and Methods Totally 308 primary breast cancer women were enrolled. The status and manifestations of sleep disorders and the status of drugs used to help fall sleep in the above breast cancer patients were assessed via the Pittsburgh Sleep Quality Index (PSQI). Result The prevalence of sleep disorders in patients at the time of initial diagnosis with breast cancer was approximately 50% (97/194), which was significantly lower than that (65.8%, 75/114) in breast cancer patients before the last cycle of chemotherapy (p0.05) . However, both groups of patients rarely used drugs to help them fall sleep (P>0.05). The mean scores for sleep latency, habitual sleep efficiency, sleep disturbance, and daytime dysfunction (1.68, 1.08, 1.65, 1.37) in breast cancer patients prior to the last cycle of chemotherapy were obviously worse than those (1.29, 0.71, 1.26, 1.01) in breast cancer patients at the time of initial diagnosis (p<0.05). Conclusion Chemotherapy mainly affects the sleep latency, habitual sleep efficiency, sleep disturbance, daytime dysfunction in breast cancer patients. Chinese breast cancer patients rarely use drugs to intervene sleep disorders.

In the past few decades, the trends towards the earlier detection of breast cancer and improvements in breast cancer treatment have increased the incidence and improved survival [1][2][3] . Currently, breast cancer is one of the most common diseases, with an estimated 1.7 million new cases in 2012, accounting for 25% of all cancers in women [4].
The incidence of sleep disorders varies based on population characteristics, breast cancer 3 stages, definitions of sleep disorders and different evaluation criteria, but it is clear that a large number of patients with breast cancer have sleep disorders [5] . Most studies report that 30% to 50% of cancer patients have sleep disorders at the time of their initial diagnosis, and the prevalence of sleep disorders is the highest in patients with breast and gynecologic cancers [6][7][8] . The proportion of breast cancer patients with sleep disorders is higher than that observed in healthy adults [9] . Insomnia is the most common sleep disorder. A study has shown that breast cancer patients have a three-fold higher incidence of insomnia than the general population [10,11] . Most of the symptoms of insomnia are subjective complaints of difficulty sleeping. The symptoms mainly include difficulty falling asleep, difficulty staying sleeping, early waking, and unstable or poor sleep quality.
All adjuvant treatments for breast cancer patients have an impact on sleep quality because of their psychological and physiological effects and side effects. Chemotherapy is thought to be particularly harmful [12,13] . Breast cancer patients have more subjective sleep disorders during chemotherapy than during non-treatment periods [14,15] .
Longitudinal studies have also shown that the quality of sleep in breast cancer patients continues to decline during the chemotherapy cycle [16] .  (Table 1).
However, both groups of patients rarely used drugs to help them fall sleep (p<0.05) ( Table   2). The mean scores for sleep latency, habitual sleep efficiency, sleep disturbance, and daytime dysfunction were better in breast cancer patients at ID than before LC (p<0.05) ( disorders are related to dysregulated immune functioning as measured by increased levels of biomarkers such as interleukin-6 (IL-6), tumor necrosis factor, and C-reactive protein.
Chemotherapy-induced inflammation can also affect sleep quality, and the side effects of chemotherapy and the drugs that are used to prevent them can also lead to increased severity of sleep disorders. For instance, using dexamethasone during chemotherapy can cause insomnia [23].
The limitation of this study is that there is no one-to-one correspondence between the patients of Chinese breast cancer at the time of diagnosis and during the last cycle of chemotherapy.
The limitation of this study is that the breast cancer patients which were enrolled are no one-to-one correspondence between the first diagnosis and during the last cycle of chemotherapy. This study does not take into account the fatigue and depression in breast cancer patients, which requires further study.
In summary, the symptoms of sleep disorders were more prevalent and severe in patients with an initial diagnosis of breast cancer than in the general population and were further  ID: Initial diagnosis (n=194); LC: the cycle of last chemotherapy (n=114); PSQI: the Pittsburgh Sleep Quality Index."+": All correlations are statistically significant (P < 0.05). All data are presented as mean±SD.