Radiation therapy is a cancer treatment using high-energy rays to destroy cancer cells. While targeting diseased areas, it can also affect healthy tissues, causing side effects. Nausea is a side effect for some patients.
Why Nausea Occurs
Nausea stems from radiation effects on the gastrointestinal (GI) tract and brain. Radiation damages rapidly dividing digestive system cells, causing irritation and inflammation. This prompts serotonin release, signaling the brain, inducing nausea.
Beyond GI tract effects, radiation stimulates the chemoreceptor trigger zone (CTZ) in brain. The CTZ detects harmful blood substances, triggering vomiting. Radiation damage or direct head radiation activates the CTZ. The vagus nerve, connecting brain to GI tract, transmits these signals.
Factors Influencing Nausea
Nausea likelihood and intensity vary by factors. Treated body area is key; radiation to the abdomen, pelvis, and brain carries higher risk. Total-body irradiation causes nausea in over 90%, while upper abdominal or craniospinal irradiation affects 30% to 90%.
Radiation dose and delivery influence nausea. Higher doses or larger daily fractions increase risk. Concurrent treatments, like chemotherapy, worsen nausea, as many chemotherapy drugs cause nausea. Individual factors like age (younger patients are more susceptible), gender, or history of motion sickness or severe nausea affect sensitivity.
Managing Nausea
Managing radiation-induced nausea involves medical and lifestyle strategies. Healthcare providers prescribe antiemetic medications to prevent or reduce nausea. These medications, like ondansetron (a 5-HT3 receptor antagonist), block nausea signals in brain and gut. Take these medications as prescribed, often before treatment, rather than waiting for nausea.
Dietary adjustments help manage symptoms. Eating small, frequent meals is easier on the stomach. Choose bland, low-fat foods (e.g., toast, crackers, applesauce), avoiding spicy, fried, or greasy options. Stay well-hydrated by sipping fluids (e.g., water, clear broths, ginger ale) to prevent dehydration, which can worsen nausea.
Simple lifestyle modifications help alleviate discomfort. Rest adequately, avoid strong odors that trigger nausea, and create a calm environment. Some complementary therapies (e.g., ginger, peppermint, acupuncture) may reduce nausea, but always discuss these with your healthcare team.
When to Seek Medical Advice
While radiation therapy nausea is often manageable, certain symptoms require immediate medical attention. Contact your healthcare team for severe or persistent vomiting, especially if unable to keep down food or liquids for over 24 hours. Signs of dehydration (e.g., dizziness, decreased urination, dry mouth, excessive thirst) require prompt evaluation, as dehydration can lead to serious complications.
Significant weight loss from inability to eat or drink, or fever with nausea and vomiting, warrant medical advice. If nausea severely impacts daily life, prevents treatment adherence, or does not improve with prescribed medications and self-care strategies, inform the healthcare team.