chemotherapy-induced peripheral neuropathy (CIPN)

What is chemotherapy-induced peripheral neuropathy (CIPN)?
Chemotherapy-induced peripheral neuropathy describes damage to the peripheral nervous system, the system that transmits information between the central nervous system (e.g. the brain and spinal cord) and the rest of the body, caused by some chemotherapy agents. Commonly used chemotherapy agents associated with peripheral neuropathy are listed in Table 1.

What are the symptoms of CIPN?
Symptoms are related to the type of nerve that is affected by the chemotherapy. Sensory nerves are at increased risk to chemotherapy associated damage compared to motor nerves. This is because most of the drugs associated with CIPN are not able to enter the well-protected central nervous system, where the cell bodies (the location of important cell sustaining functions) of motor nerves are located. Therefore, patients often experience sensory symptoms such as numbness, tingling, or burning sensations. Patients may also notice that things that are not normally painful are now painful (called allodynia). For example, after receiving cisplatin, some people report that touching cold things or cold breezes over the skin are painful (CITE). In addition, patients may develop decreased sense of vibration, diminished or absent reflexes.1-3 Sensory symptoms often begin in the tips of the fingers or toes and may progress into a stocking and glove pattern. While it is less common, some people can develop weakness.2 Symptoms are described by drug class in Table1.

The onset and resolution of symptoms is variable. Some drugs may cause symptoms during or immediately after the first dose. The platinum compounds have been reported to have a delayed onset of symptoms, up to several weeks after the last dose. The severity of symptoms is related to the cumulative dose of the drug received.1,2 Patients with pre-existing peripheral neuropathy may be at risk for a more severe and long-lasting neuropathy. It is unclear what proportion of patients have a complete resolution of symptoms or how long it takes for symptoms to resolve because there are no published studies that have examined these questions. However, many patients report to their health care providers that their symptoms improve or totally resolve over time.