1 INTRODUCTION
The internationally recognized GLOBOCAN 2020 database1shows that in 2020, female breast cancer (BC) will for the first time overtake lung cancer as the most common cancer in the world and the leading cause of death in women. Due to the continuous progress of early screening, surgical treatment, adjuvant therapy and other technologies, the 5-year survival rate of breast cancer patients reaches 83.2%.2 However, due to surgical trauma, postoperative radiotherapy and long disease duration, a series of complications, such as anxiety, depression, pain, sleep disorders, etc., are still inevitable, therefore, reducing the complications and improving the quality of life of breast cancer patients deserve our attention. Virtual reality (VR) technology is a non-invasive simulation technology with three-dimensional dynamic views generated in computer-generated images or environments, and the commonly used devices are head-mounted displays and headsets3. The commonly used devices are head-mounted displays and headsets. In recent years, virtual reality technology has been gradually applied to medical and healthcare systems due to its ability to provide a multi-sensory, immersive, interactive, motivational stimulation and feedback environment that is fun, safe, easy to operate, and easy to promote.4 It has been gradually applied to medical and healthcare systems. Currently, there have been several studies applying VR technology to the symptom management of certain diseases, such as Parkinson’s disease5 stroke, Alzheimer’s disease6,7 and chronic obstructive pulmonary disease (COPD)8 etc., all of which have shown initial success. With the continuous development of VR, immersive virtual reality (IVR) is becoming more and more popular in clinical rehabilitation care. Compared with non-immersive and semi-immersive virtual reality technologies, IVR mobilizes multi-senses (vision, hearing, smell, touch, kinesthetic, proprioception) through an immersive experience, immersing patients in a three-dimensional dynamic The virtual environment in which the patient has immersed a three-dimensional dynamic view and physical behavioral interaction is more realistic and more able to mobilize the autonomy of the experience.5 The IVR can be used in a variety of ways. Several studies have found that IVR can affect patients’ cognitive dysfunction9, pain10, sleep disorders11 and etc., but the results have not been harmonized. Currently, the effectiveness of IVR interventions for breast cancer patients is controversial, and previous studies12 mainly evaluated the effects of non-immersive and semi-immersive VR technologies or included class experimental studies, and a systematic review of IVR for symptom management in breast cancer patients has not been reported.