4  | DISCUSSION
This paper evaluates the effectiveness of IVR technology-based intervention for breast cancer patients through meta-analysis, and the results show that the study participants’ symptoms of anxiety, depression, pain, and fatigue were alleviated, and their quality of life was improved, and the difference was statistically significant.
With the transformation of the biopsychosocial medical model, the impact of negative emotions on breast cancer patients has attracted more and more attention. Postoperative breast loss, wound pain, worry about disease prognosis, nausea and vomiting due to chemotherapy, hair loss, etc. can cause anxiety, depression and other adverse psychological symptoms, which can seriously affect the prognosis and regression of patients20. The results of this study showed that Reynolds et al.17 study concluded that the intervention effect of IVR technology on anxiety in breast cancer patients was not significant, probably because the study subjects reported lower levels of anxiety before the intervention, resulting in no significant difference between before and after the intervention; the rest of the studies reported that IVR had a significant improvement in anxiety and depression symptoms in breast cancer patients, which was consistent with the meta-analysis of the effect of the relevant VR interventions on breast cancer.21 The results are consistent with the fact that the principle of action may be to utilize the distraction mechanism. In the study included in this paper, the researchers based on IVR technology, immersed patients in wonderful natural scenery such as the sea, forests, waterfalls, etc., and cooperated with breathing and movements to stretch the body and mind and achieve a state of relaxation, to achieve the purpose of alleviating anxiety in breast cancer patients by distracting attention from the disease and the medical environment in which they live. And Zeng et al.22 ’s meta-analysis of cancer patients showed that VR-based interventions did not have a significant effect on anxiety relief. The reason for this may be that although non-immersive VR technology uses virtual scenes, it is mainly connected to the virtual environment through the computer screen, and the patients are not detached from the real world and are not in it, so the authenticity and fun are not as good as immersive virtual reality technology, and may be affected by the hospital environment and other factors, so the patients cannot completely relax their bodies and minds to achieve the effect of relieving anxiety.
It has been found that fatigue, with a prevalence of about 90% in breast cancer patients, is one of the most common and serious complications in breast cancer patients and is often not effectively treated23 , which may be affected by adverse reactions such as nausea, vomiting, loss of appetite and bone marrow suppression produced by chemotherapy; and fatigue will aggravate patients’ negative emotions such as anxiety and depression, which will aggravate their physical and mental burdens and further affect their quality of life. Some studies have observed postoperative breast cancer patients and found that sleep deprivation aggravates pain, while good sleep promotes wound healing and tissue repair24 . The results of this study showed that interventions based on IVR technology can improve fatigue symptoms in breast cancer patients, which is consistent with Cheng et al.25 class experimental study results, but different from Burrai et al.11 The results of meta-analysis of IVR-based interventions for cancer chemotherapy patients, the reasons for this difference may be (1) the small sample size of the included studies; (2) due to the nature of the virtual reality, blinding could not be implemented for all interventions, so it may lead to bias, and the limited number of the included studies did not allow for the analysis of the source of the bias through the funnel plot; and (3) the period and frequency of the interventions in the included studies, varied greatly between control groups.
Postoperative pain is one of the most common complications of breast cancer, and studies have shown that about 25% to 60% of patients will develop chronic pain that lasts for 7-12 years, which can cause the body to produce autonomic responses, such as increased heart rate, increased blood pressure, nausea and vomiting, which seriously affects the quality of life of breast cancer patients.26 Currently, non-pharmacological interventions to control pain through IVR technology are receiving increasing attention, and its mechanism of action may be focus shifting, when the patient is immersed in the virtual environment, the attention will be shifted away from the painful stimuli, and in this way, weakening its responsiveness to injurious neural signals, and thus pain perception decreases.27 Of the studies included in this paper, Mohammad et al.19 intervened in breast cancer chemotherapy patients through immersive virtual environments, such as deep-sea diving in the Ocean Rift Valley, combined with morphine medication for pain relief, and after 4 months of intervention, the results showed that compared to medication alone for pain relief, the IVR-based intervention combined with medication was more effective in relieving pain, and the side effects of the medication, such as nausea, vomiting, and constipation, were significantly reduced; Reynolds et al.17 An at-home IVR intervention that allowed patients to pile rocks on a waterfall, jump in a mountain range, and write on a beach showed significant pain reduction after four weeks of intervention, with pain relief lasting for at least 48 hours post-intervention. Although evidence suggests that IVR is effective in relieving immediate or short-term pain, the long-term effects have not been proven, and more high-quality studies need to be included in the future to determine the long-term efficacy of IVR techniques for breast cancer pain.