Relationship between heart rate variability and cancer management

Abstract

In patients with advanced cancer, the prevalence rate of cardiac autonomic neuropathy (CAN) is high, and the prognosis of patients with CAN is generally poor. Although mechanisms including inflammation, infection, metabolism, neurodegeneration, toxic processes, and cancer treatment have been proposed as etiologies of CAN in cancer patients, these mechanisms have not been completely elucidated, and their relationship has only been described indirectly. A study involving 127 cancer patients revealed that both the disease and its treatments can lead to a decrease in heart rate variability (HRV) indicating the autonomic imbalance. Because managing CAN is essential for improving the survival and quality of life of patients with cancer, patients and specialists can work together to customize cancer treatment and management using HRV as an index.

Key Words: Cardiac autonomic neuropathy; High frequency; Low frequency; Standard deviation of all normal-to-normal intervals; Very low frequency

Core Tip: Heart rate variability (HRV) serves as an indicator of autonomic nervous system function. A reduction in HRV is associated with system imbalances and potential health concerns in patients with cancer. A study involving 127 cancer patients revealed that both the disease and its treatments can lead to a decrease in HRV. Additionally, psychological factors such as stress and anxiety also influence HRV levels. Therefore, monitoring HRV can aid in the assessment of cancer patients’ health status, prognosis, and the formulation of personalized treatment plans.

INTRODUCTION

The prevalence rate of cardiac autonomic neuropathy (CAN) in patients with advanced cancer is 70%-80%. The 1-year survival rate of patients with CAN is half that of patients without CAN, and CAN is considered an indicator of poor prognosis[1-3]. However, a few studies have reported that the presence of CAN is associated with a poor prognosis even in cancer survivors who are expected to survive for a long time[4-6]. Thus, the association between cancer and CAN is complicated by several confounding factors, such as chemotherapy[7], the patient's general health status, and their ability to perform activities of daily living[8]. Mechanisms such as inflammation, infection, metabolism, neurodegeneration, toxic processes, and cancer treatment have been proposed as etiologies of CAN in cancer patients[9]. However, these mechanisms have not been completely elucidated, and their relationship has only been described indirectly. In recent years, studies using human breast cancer tissues and mouse and rat breast cancer models have demonstrated that autonomic nervous system function is related to cancer growth and metastasis, providing insights into the direct relationship between the two.

CAN IN PATIENTS WITH CANCER

The paper by Deng and Song[10] is an observational study that used heart rate variability (HRV) as an established non-invasive screening method[11] for CAN to investigate the HRV of 127 consecutive cancer patients (age: 62.8 ± 12.4 years; 73 men and 54 women; tumor locations: Head and neck 37; chest 62; digestive system 16; and other: 12; tumor stage: I: 15; II: 27; III: 52; and IV: 33), who were recruited comprehensively from a group of cancer patients with all severity levels. The primary endpoint was to compare the time domain (five indices, including standard deviation of all normal-to-normal intervals) and frequency domain (three indices, including low frequency, HRV indices derived from 24-hour ambulatory, and Holter monitoring with typical reference values)[11,12].

Their findings showed that all HRV indices in patients with cancer were significantly lower than the normal reference values. The decrease in HRV in patients with cancer did not show any significant relationship with general patient background, such as sex and age, or location of the tumor. However, a significant decrease was observed in all HRV indices as the degree of tumor stage increased. Unfortunately, only a limited number of HRV indices are reported in the present study, particularly in the frequency domain.

Managing CAN is essential for improving the survival and quality of life of patients with cancer[13]. Their study shows that patients and specialists can work together to customize cancer treatment and management using HRV as an index. However, the results of this study provide insights derived from univariate analyses and do not address potential confounding factors other than the items examined[7,8].

CONCLUSION

Nevertheless, their study results may inspire future randomized prospective studies to determine the clinical utility of HRV as an index for monitoring the management of patients with cancer.