Effect of Exercise in the Management of Peripheral Neuropathy

Chemotherapy-associated peripheral neuropathy is a common complication in patients undergoing taxane and platinum-based chemotherapy. Peripheral neuropathy may cause the patient's activities of daily living to be inhibited, deterioration of quality of life, reduction of treatment dose, and even discontinuation of treatment. In the literature, different studies have been carried out using many pharmacological and non-pharmacological approaches to manage this problem, but no approach that has been shown to be effective in its management has not been clearly defined until now. One of the approaches whose effectiveness is evaluated in management is exercise. Published case reports and a few experimental studies examining small patient groups have been found to have significant benefits in the management of peripheral neuropathy. This study was planned to determine whether exercise is effective in managing associated peripheral neuropathy in oncology patients.

General Information Cancer is one of the most important health problems in the world and our country. Despite significant developments in cancer treatment, treatment-related side effects can lead to adverse effects on the quality of life of patients, limitation of their activities, and even restriction of the treatment dose and discontinuation of the treatment, which may adversely affect the response of the patient to treatment.

Antineoplastic agents used in cancer treatment provide treatment of cancer or prevent its progression by preventing the division and proliferation of cancer cells. However, these drugs cause many important side effects such as anemia, diarrhea, nausea, vomiting, infections, fatigue, alopecia, infertility, pain, and peripheral neuropathy in the patient by affecting not only cancer cells but also normal cells and body structures.

Peripheral neuropathy is a significant side effect that adversely affects patients' quality of life receiving taxane or platinum-based chemotherapy. The incidence of chemotherapy-associated peripheral neuropathy varies between 19 and 85%, depending on the type of chemotherapy protocol administered, the drug dose used in the treatment, and the duration of administration. The incidence of peripheral neuropathy, according to the type of antineoplastic agent applied, is between 70-100% in platinum-administered patients, 11-87% in taxane-administered patients, 20-60% in thalidomide-administered patients, and 60-65% in ixabepilone-administered patients. The most common antineoplastic agents causing peripheral neuropathy are platinum (oxaliplatin and cisplatin), vinca alkaloids (vincristine and vinblastine), and taxanes (paclitaxel, docetaxel), proteasome inhibitors (bortezomib), and immunomodulatory drugs (thalidomide). These chemotherapeutic agents, which cross the blood-brain barrier, affect the dorsal root ganglia and peripheral axons in the spinal cord, causing changes in motor, sensory and autonomic neurons, causing the development of peripheral neuropathy.

Many factors such as age, concomitant diabetes mellitus history, microtubules or mitochondrial damage, oxidative stress, changes in ion channel activity, and damage to the myelin sheath play a role in the development of peripheral neuropathy. Sensory, motor, and autonomic symptoms may develop in patients with chemotherapy-related peripheral neuropathy. First, patients develop sensory symptoms such as numbness in the hands and feet, tingling, change in the sense of touch, paresthesia, dysesthesia, and patients usually describe these sensory changes as a feeling of wearing gloves and socks. As the picture progresses, spontaneous burning, fever, electric shock, mechanical or thermal allodynia, and hyperalgesia may also develop in patients. In severe cases, these symptoms can go as far as loss of sensory perception. Muscle weakness, gait, and balance disorders that increase the risk of falling are frequently reported motor symptoms by patients. Orthostatic hypotension, constipation, urinary dysfunction, and sexual dysfunction are common autonomic symptoms in patients. While these symptoms improve over time with the discontinuation of chemotherapy in some patients, they can be permanent because neuron damage occurs in most patients. Therefore, approaches presented in the management of peripheral neuropathy in the literature are quite limited.

In a systematic review of the effectiveness of pharmacological approaches in the management of chemotherapy-associated peripheral neuropathy, it was reported that the use of pharmacological agents such as duloxetine, gabapentin, acetyl-L-carnitine (ALC), amitriptyline, cannabinoid, lamotrigine, and topical baclofen could be recommended in the management of this problem. However, studies evaluating the efficacy of these pharmacological agents were found to be insufficient in terms of evidence.

Non-pharmacological approaches whose effectiveness has been evaluated in the management of chemotherapy-related peripheral neuropathy are acupuncture, acupressure, neurofeedback, scrambler therapy, cold application, reflexology, massage, exercise, relaxation techniques, physical therapy, and magnetic therapy.

Exercise, one of these approaches, has been reported to be effective in reducing pain, numbness, tingling, loss of sensation, and increasing muscle strength and balance due to peripheral neuropathy in different patient groups. In a quasi-experimental study conducted on patients with a modified neuropathy score (range 0-20) of 5 and above, it was observed that closed kinetic exercises decreased the neuropathy score and increased the balance. A 10-week home-based exercise program for breast cancer patients has been shown to improve symptoms of peripheral neuropathy. In a randomized controlled study with patients with metastatic colorectal cancer, resistance and balance exercises were applied to the experimental group for eight weeks. According to the results of the study, when the experimental group and the control group were compared, peripheral neuropathy symptoms remained the same, while a significant improvement was found in balance functions. In the study of Bland et al., it was stated that exercise significantly improved the CIPN20 score and reduced peripheral neuropathy in patients with breast cancer receiving taxane therapy. However, although the number of studies showing exercise efficacy in managing chemotherapy-associated peripheral neuropathy is quite limited, studies with small samples have low evidence strength.

This study was planned to determine whether exercise is an effective approach in the management of chemotherapy-associated peripheral neuropathy in oncology patients.