Clinical research: Stimulation of the vagus nerve as a potential cancer treatment

Professional info

- Vagus nerve activity can be measured using the heart rate variability (HRV) that is recorded in an ECG (electrocardiogram).
- Various clinical studies have shown that a higher HRV is related to an improved prognosis (longer survival rates or lower tumor markers) for different types of cancer.
- The pilot study in patients with advanced colon cancer revealed important trends, but not statistically significant, where CEA levels remained nearly unchanged in the controls, while it showed a constant apparently declining pattern in the HRV-biofeedback group.

 

Location: Vrije Universiteit Brussel (VUB), Belgium
Collaboration: Prof. Yori Gidron, Marijke De Couck, Inge De Leeuw

 

Vagus nerve

Low vagus nerve activity is related to a worse cancer prognosis. The vagus nerve is one of the twelve cranial nerves that extends throughout the human body (larynx, trachea, oesophagus, heart, lungs, stomach and abdominal organs) and performs a variety of important functions, such as stimulating the digestive system. It is also the most important nerve of the parasympathetic nervous system, which means that it helps to calm your body after a stress response by, among other things, slowing down your heart rate and lowering your blood pressure.
The scientific understanding of how cancerous tumors and metastases are formed and develop has changed, and today a greater emphasis is placed on the immediate environment of the tumor cells within the body and the presence of a number of processes that make the prognosis worse. These processes are excessive inflammatory responses, oxidative stress (a cellular metabolic condition that damages DNA) and sympathetic neurotransmitters (biochemical carriers that trigger a stress response in the body – increasing the heart rate). The activity of this cranial nerve, the vagus nerve, can change or counter these three processes.
Vagus nerve activity can be measured using the heart rate variability (HRV) that is recorded in an ECG (electrocardiogram). Various clinical studies have shown that a higher HRV is related to an improved prognosis (longer survival rates or lower tumor markers) for different types of cancer.

 

Why did we choose this project?

Various clinical studies have published results on the relationship between vagus nerve activity and cancer prognosis in certain types of cancer. 
This project evaluated a non-invasive approach via deep paced breathing (HRV-biofeedback) and via non-invasive vagal nerve stimulation (VNS) to predict prognosis and which could possibly bring a new treatment to patients.

 

The aim of the project

The aim of the project was to validate the published data on the role of the vagus nerve in cancer and to confirm the relationship between HRV and cancer prognosis. In the final part of the project, a pilot study was initiated to evaluate if HRV-biofeedback may reduce the tumor marker CEA (Carcinoembryonic antigen) and improve quality of life in patients with advanced colon cancer.

 

How did we approach the problem?

A study was performed to validate the relationship between vagus nerve activity and cancer prognosis in 4 types of cancer (prostate (n=113), pancreatic (n=348), lung (n=120) and breast cancer).
Several studies with healthy volunteers were conducted to compare the deep paced breathing (HRV-biofeedback) and non-invasive vagal nerve stimulation (VNS) as interventions to activate the vagus nerve activity. The results of this study were consequently implemented in the pilot study with patients.
The preclinical study which evaluated the reduction of tumor burden in tumer-bearing rats with an implanted VNS was stopped due to failure of the tumor development in the rats. No conclusion could be made.
The pilot study in patients with advanced colon cancer (stage 4) was set-up as a multicenter study (UZ Brussels and UZ Ghent). Patients who performed 3 months of HRV- biofeedback were compared to controls, matched on cancer type, stage and treatment.  

 

What did we find?

Based on the retrospective studies in 4 cancer types, a significant association between vagus nerve activity and prognosis in those cancer types was found and published in 3 scientific papers.
The pilot study in patients with advanced colon cancer (stage 4) revealed important trends, but not statistically significant, where CEA levels remained nearly unchanged in the controls, while it showed a constant apparently declining pattern in the HRV-biofeedback group. These preliminary results need to be confirmed in a large randomized controlled trial.

 

Based on the project results, our message to patients:

Although a larger clinical trial is needed to confirm the effect of HRV-biofeedback on several types of cancer, already data in the retrospective study and the pilot study show a positive trend.
If patients want to start using the non-invasive HRV-biofeedback tool, always consult your doctor first. Again, a large randomized controlled trial needs to be set-up to gain more data on the effect of the vagus nerve activity on cancer in order to recommend as therapeutic useful.