Background. Complaints of sleep disturbances are common in patients with breast cancer and may affect their quality of life. Insomnia, fatigue, and sleep fragmentation were previously reported in these patients. However, no studies reported polysomnographic data to elucidate the etiology of these symptoms. We hypothesized that patients with breast cancer will have considerable abnormalities on their monitored overnight sleep studies including sleep disordered breathing, periodic leg movement, and spontaneous arousals.Methods. Data from sleep studies were prospectively collected from cancer patients who undergo a sleep study at the MD Anderson Sleep Center and who consented to participate. All breast cancer patients who underwent a poylsomnogram between 1/30/2007 and 4/1/2009 and signed informed consent were identified. The prospectively collected data included demographics, breast cancer clinical data and treatment, as well as polysomnographic data.Results. Sixty-nine patients (68 female, 1 male) were identified with breast cancer. All patients underwent a formal sleep consultation. The median age was 56 (range: 38 to 75 years), and the median body mass index (BMI) was 33 kg/m2 (21 to 52).Tumor characteristics were as follows: 55 patients (80%) had invasive ductal carcinoma, 8 (12%) had invasive lobular carcinoma, 5 with ductal carcinoma in situ (7%), and 1 unknown (1%). ER/PR was positive in 44 patients (64%), and HER-2 positive in 9 patients (13%). Five patients (7%) had stage 0, 12 (17%) had stage I, 30 (44%) had stage II, 12 (17%) had stage III, and 10 (15%) had stage IV disease. Twenty-four patients (35%) had completed treatment, 10 patients (15%) were receiving chemotherapy, and 34 patients (50%) were receiving hormonal therapy.Fifty-one patients (74%) were referred for daytime sleepiness and fatigue, 11 (16%) for sleep apnea symptoms, 1 (1%) for pulmonary hypertension and 6 (9%) for insomnia. In 55 patients (81%), the median Epworth Sleepiness Score 12 (4 to 21) was consistent with excessive daytime sleepiness.Sleep fragmentation was noted in all patients with a median sleep efficiency of 86% (36% to 98%) and a median Arousal Index of 33 arousals/hour of sleep (7 to 118). Furthermore, the median percentages of delta sleep (deep sleep) and REM sleep were notably diminished at 1% and 13% respectively. Sleep disordered breathing was noted with a median Apnea Hypopnea Index (AHI) of 10 apneas and hypopneas/hour of sleep (0 to 68). Only 2 patients were noted to have significant periodic limb movements with arousals. There was no difference in these abnormalities between treatment groups (chemotherapy, hormonal therapy, or no treatment).Conclusions. This is the first report of polysomnographic data in breast cancer patients. Our data show that sleep disordered breathing (obstructive sleep apnea) is a cause of sleep disturbance in a number of these patients. Conversely, periodic leg movement was not common among these patients. Of interest, the high Arousal Index indicates a high frequency of spontaneous arousals not explained by apnea or hypopnea and these findings did not vary across treatment types. These findings show unique abnormalities in the sleep architecture of breast cancer patients that are provoking and warrant further study.
Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 5036.