How exercise affects cancer survivors with chemotherapy-induced peripheral neuropathy

Background

Significant advances in cancer diagnosis and treatment have resulted in an estimated 43.8 million cancer survivors worldwide. However, long-lasting nerve damage is a common complication in cancer survivors with chemotherapy-induced peripheral neuropathy (CIPN), leaving them with pain, numbness and weakness in the hands, feet and arms.

Despite the prevalence of CIPN, there are currently no treatment options to reduce the impact of this nerve damage on patient function. Exercise and balance training have been demonstrated to successfully improve balance, mobility, and nerve function in other forms of peripheral neuropathy. However, such balance training interventions have not been comprehensively examined in cancer survivors with CIPN.

We have established an assessment protocol to examine the extent of peripheral nerve damage due to chemotherapy, incorporating a full spectrum of clinical tests. We have conducted a preliminary study of exercise and balance training in cancer survivors with CIPN utilising this assessment protocol to provide necessary evidence of the improvement in CIPN symptoms.

Interim results from 12 patients demonstrated significant improvements in objective nerve function (signalling between nerves), patient-reported nerve symptoms (such as pain), patient-reported quality of life, and standing balance following an eight-week exercise intervention.

Aims and objectives

Our aims are:

• To investigate the impact of exercise on nerve function, quantified through a range of neuropathy assessment tests.
• To determine the effect of exercise on gait, balance, fine motor function (movement of small muscles such as fingers), and quality of life in cancer survivors with CIPN.

We hypothesise that significant improvements will occur in nerve function, and that we will identify significant improvements in nerve conduction (how fast an electrical pulse moves through your nerve) and nerve excitability parameters (the level of damage to nerves) resulting in functional benefits in survivors with chemotherapy-related nerve damage.

We hypothesise that the exercise intervention will improve gait and balance, fine motor function, and patient-reported neuropathy symptoms. Furthermore, we hypothesise that our novel balance assessment will be a quick and easy means of assessing balance deficits related to CIPN.

How it will be done

Patients will be randomised into two groups in a follow-up design: an eight-week exercise programme or a non-exercise control group. The exercise programme will consist of three weekly one-hour sessions split into equal divisions of cardiovascular, resistance, and balance training exercise. The assessment protocol will enable assessment of the effects of exercise on:

1. neurological function
2. patient fitness, fine motor function and balance
3. patient-reported outcomes via validated questionnaires
4. gait assessment via a state-of-the-art quantitative gait analysis system. A novel standing balance assessment, involving the analysis of balance disturbances during tasks requiring patients to reach for objects located out of their immediate field of vision, will be piloted.

Potential impact

Cancer survivorship is a major public health challenge, and it is vital to understand the potential impacts of chemotherapy-related side-effects on long-term quality of life in cancer survivors. The proposed study will provide the first comprehensive investigation of the effects of exercise on peripheral nerve health, gait, balance, fine motor function, and quality of life in cancer survivors with persisting nerve damage resulting from treatment.

Accordingly, this project has the potential to establish both the specific effects of exercise as an effective, low-cost treatment for chemotherapy-induced peripheral nerve damage, and the key outcome measures for sensitive assessment of mobility and balance deficits in this population.