Chemotherapy, a common cancer treatment, targets rapidly dividing cells to eliminate cancerous growths. This powerful therapy can also affect healthy cells, leading to various side effects. One such side effect is nerve damage, known as chemotherapy-induced peripheral neuropathy (CIPN). CIPN is a common complication, affecting between 30% and 40% of patients undergoing chemotherapy, and can significantly impact quality of life.
Understanding Neuropathy
Neuropathy is nerve damage or dysfunction, often causing numbness, tingling, muscle weakness, and pain. When chemotherapy-induced, it primarily affects the peripheral nervous system (PNS). The PNS includes all nerves branching from the brain and spinal cord to the rest of the body, acting as a communication network.
The PNS has different nerve types. Sensory nerves transmit sensations like touch, pain, temperature, and vibration. Motor nerves carry signals to muscles for voluntary movement. Autonomic nerves regulate involuntary functions like heart rate, blood pressure, and digestion. Neuropathy occurs when any of these nerve types are damaged.
How Chemotherapy Induces Neuropathy
Certain chemotherapy drugs cause nerve damage, with mechanisms varying by agent. Platinum-based compounds like cisplatin and oxaliplatin can accumulate in nerve cells, damaging DNA or disrupting protein synthesis. Oxaliplatin can induce both acute neuropathy during infusion and a chronic form with cumulative dosage. Taxanes, including paclitaxel and docetaxel, interfere with microtubules, essential for nerve cell structure and transport. This disruption can lead to axonal damage.
Vinca alkaloids, such as vincristine, also target microtubules, inhibiting their assembly and disrupting axonal transport. This can lead to nerve fiber degeneration. Nerves are vulnerable to these drugs due to their long axons and high metabolic demands. While mechanisms differ among drug classes, the common outcome is impaired nerve function.
Recognizing Symptoms of CIPN
CIPN symptoms vary depending on affected nerve types and damage extent. Sensory nerves are most commonly impacted, leading to numbness, tingling, and a “pins and needles” feeling, often in the hands and feet. Patients might experience burning, shooting, or electric-shock-like pain, and heightened sensitivity to touch or cold. This sensory alteration frequently follows a “stocking-glove” pattern, affecting the extremities first.
Motor nerve damage, though less frequent, can lead to muscle weakness, particularly in the hands and feet. Individuals may find it difficult to perform fine motor tasks like buttoning shirts or writing. Balance problems and gait disturbances, such as foot drop, can also occur, increasing fall risk. Severe motor symptoms can significantly limit daily activities.
Autonomic symptoms are less common but can include dizziness (orthostatic hypotension), constipation, or altered urinary function. While onset can be sudden or gradual, sensory symptoms generally appear first and may persist for months or even years after chemotherapy ends.
Strategies for Managing CIPN
Managing CIPN involves medical and supportive strategies to alleviate symptoms and improve quality of life. Medical approaches include adjusting chemotherapy doses or considering alternative agents under supervision if neuropathy becomes severe. For painful CIPN, duloxetine, an SNRI, is the only agent recommended by the American Society of Clinical Oncology (ASCO). Other medications like gabapentin or pregabalin are sometimes used, though evidence for their effectiveness is limited.
Supportive care and lifestyle adjustments are important. Physical therapy can improve balance, strength, and coordination, while occupational therapy assists with adapting daily tasks and maintaining fine motor skills. Cold therapy, using frozen gloves and socks during infusions, has shown promise in reducing CIPN symptoms by constricting blood vessels and limiting drug exposure. Regular, low-impact exercise can also be beneficial.
Complementary therapies like acupuncture have been explored for symptom relief. Some meta-analyses suggest acupuncture may help reduce pain and improve functional limitations. Patients should discuss any complementary therapies with their oncology team to ensure safety and avoid interference with cancer treatment. Maintaining good nutrition and protecting affected areas from injury, such as wearing appropriate footwear, are also important practical measures.