Analysis of Sleep and Activity Patterns in Pre-menopausal Breast Cancer Patients After Taking Tamoxifen Using a Wrist-worn Internet of Things Device

Breast cancer is the most common malignant tumors occurring in women worldwide. Treatments include surgery, radiation therapy, chemotherapy, hormone therapy, and target therapy. As multidisciplinary treatment improves breast cancer survival, there is a growing interest in the quality of life of breast cancer survivors. Common symptoms that patients with breast cancer continue to complain of during or after their treatment include fatigue, pain, depression, sleep disorders, weight gain and hot flashes.

There are only a few studies investigating sleep problems in breast cancer patients, which mostly relied on surveys. A commonly used survey evaluation method is the Pittsburg Sleep Quality Index (PSQI). Using PSQI, one study reported that 66% of the Chinese breast cancer survivors had sleep disorders and 49% had significantly reduced sleep efficiency and time in bed. The group with sleep disorder had lower quality of life, more depression and higher overall stress than the group without sleep disorder. Another survey of breast cancer patients over 69 years old found that pain, fatigue and depression were related to sleep, and that fatigue was the strongest predictor of sleep disorders.

A recent study found that postmenopausal breast cancer patients, starting hormone therapy with aromatase inhibitor, total sleep time and sleep efficiency declined without statistical significance. However, 58% of Korean breast cancer patients are pre-menopausal patients aged 49 or younger, and thus, most patients take tamoxifen and goserelin instead of aromatase inhibitors after surgery. In this reason, results of aromatase inhibitor can not be applied in this population. As previous studies on the effects of tamoxifen on sleep were conducted retrospectively, objective comparisons of before and after applying tamoxifen are difficult and the long-term effects of tamoxifen are difficult to understand.

The aim of this study is to observe the sleep and activity patterns of pre-menopausal breast cancer patients taking tamoxifen using a wrist-worn internet of things device and questionnaires.