Impact of Cancer and 12 Weeks of Chemotherapy on the Balance of the Autonomic Nervous System in Cancer Patients

Cancer and its treatment itself (especially chemotherapy) is associated with number of negative effects on the human body. These include mainly cardiac toxicity, peripheral neuropathy, bone loss, depression, anxiety, nausea, pain, cognitive changes, fatigue, fitness reduction and more. Fatigue is one of the most common negative effects, often persists long after treatment and is described as insurmountable and is associated with lower parasympathetic activity. The autonomic nervous system (ANS) is the main homeostatic regulatory system of the body, it regulates involuntary physiological processes. We believe that this part of the peripheral nervous system can be negatively affected by cancer and chemotherapy, which can have a negative impact on all the processes that control this system. Most drugs used in oncology lead to chemotherapy-induced peripheral neuropathy and are expected to have an influence on the autonomic nervous system. Activity and balance of the autonomic nervous system depend on a range of dynamically changing and quantitatively different conditions such as age, stress, physical activity, sleep, illness, fatigue and more. Methods: To evaluate ANS activity, spectral analysis of heart rate variability (HRV) was assessed. During treatment, 19 oncological patients with prescribed adjuvant chemotherapy measured HRV 3 times a week using a chest strap with a HRV monitor mySASY and mySASY software. Parasympathetic activity (PA), sympathetic activity (S), total score (TS) and total power (TP) were selected as indicators of ANS activity. The patients were women aged 50.38 ± 10,29 with BMI 25,72 ± 4,16. The mean values for the first 14 days of treatment and then for 14 days after 12 weeks of treatment were compared. Data normality was verified by Kolmogorov-Smirnov test (K-S) and static significance was calculated by t-test. All statistical tests were performed at a significance level of 5%. Results: There was a significant decrease in values for three parameters. The PA decreased from 3,80 ± 1,56 to 3,14 ± 1,67 (p = .03), TP decreased from 3,65 ± 1,87 to 2,82 ± 2,08 (p = .04), TS decreased from 3,40 ± 1,67 to 2,67 ± 1,73 (p = .01). Sympathetic activity was somewhat but not significantly higher, increased from 6,74 ± 1,22 to 6,80 ± 1,44 (p = .83). Conclusion: During the 12 weeks of treatment with adjuvant chemotherapy, there was a significant reduction in parasympathetic activity, total score, and total power. A decrease in PA is usually associated with lower regenerative abilities of the organism, a decrease in TP is associated with a decrease in the activity of the entire ANS. TS evaluates the total power and balance of both ANS branches. The higher the values, the more the body is regenerated and ready for further stress and response to stress.