Introduction/Background The vagal nerve may have protective roles cancer. Its activity is indexed by heart-rate variability (HRV). This study aimed to examine the prognostic role of HRV in women with ovarian cancer.

Methodology This was a retrospective comparative cross-sectional study. Information obtained from medical records of patients with histologically confirmed ovarian cancer treated at a single institute, between the years 2014–2021. Background variables that were obtained included age, stage, white blood cells count (WBC) date of death or date of last contact, which ever came first. HRV, the index of vagal nerve activity, was derived from patients’ 10 sec ECG near diagnosis.

Results 104 women were included in our final cohort. Mean age was 64.7. 11.4%, 4.9%, 54.5%, 29.3% of the women were stage I,II, III and IV respectively. After controlling for known prognostic factors log-HRV tended to significantly predict a lower risk of death (R.R = 0.20, 95% CI: 0.04 – 1.06) as well as the ratio of HRV/WBC (R.R = 0.34, 95% CI: 0.13 – 0.88. Since HRV declines with age, we repeated the test with HRV/WBC in patients below 60 versus above 60. In this multivariate Cox regression, the ratio of (log)HRV/WBC tended to significantly predict Overall survival (OS) only in younger patients (O.R = 0.10, 95%CI: 0.01 – 1.27). We also confirmed association between cancer stage and survival only in women with low HRV but not in those with high HRV. (X²(1) = 4.08, 2.10, p > 0.05).

Conclusion We confirmed that higher HRV at diagnosis tended to significantly predict a better chance to survive. HRV/WBC ratio tended to significantly predict OS, but only in patients younger than 60 years old. The findings of our study suggest that vagal nerve activity, indexed by HRV, may be a new independent prognostic factor in ovarian cancer.