Heartburn, characterized by a burning discomfort in the chest or throat, occurs when stomach acid backs up into the esophagus, a process known as gastroesophageal reflux disease (GERD). Gastrointestinal side effects, including acid reflux, are a frequent complication of cancer treatment. Chronic acid reflux affects a large number of people undergoing chemotherapy, ranging from one-third to one-half of patients. Chemotherapy agents often irritate the digestive tract, leading to this uncomfortable side effect.
The Direct Link: How Chemotherapy Affects the Digestive Tract
Chemotherapy agents target and destroy rapidly dividing cells, but they cannot distinguish between cancer cells and healthy cells. The cells lining the entire gastrointestinal tract are constantly renewing and are highly susceptible to damage from these treatments. This damage leads to irritation and inflammation of the mucous membranes, called mucositis, which in the esophagus is known as esophagitis.
This inflammation directly mimics or worsens heartburn by making the esophageal lining hypersensitive to stomach acid. Certain chemotherapy drugs, including 5-fluorouracil, methotrexate, and cytarabine, are known to cause this mucosal injury. When the esophageal lining becomes inflamed, it can also impair the function of the lower esophageal sphincter (LES), the ring of muscle separating the esophagus from the stomach. The LES normally remains closed, preventing acid from flowing back up, but its effectiveness can be compromised by the accompanying inflammation, allowing acidic stomach contents to reflux more easily, causing the burning sensation.
Chemotherapy frequently causes severe nausea and vomiting, which increases pressure inside the abdomen. This physical pressure can forcefully push stomach acid past a weakened LES and into the esophagus, leading to further irritation and damage.
Distinguishing Symptoms: Identifying Other Potential Causes
Not all heartburn-like symptoms during treatment are solely a result of chemotherapy. Many supportive medications given alongside chemotherapy can independently cause or worsen acid reflux. For example, steroids, often used to manage side effects, and some pain medications, such as non-steroidal anti-inflammatory drugs (NSAIDs), are known to injure the esophageal lining.
Infections are another distinct cause, particularly fungal esophagitis, which is common in patients with a suppressed immune system. This condition is usually caused by an overgrowth of Candida yeast and presents with pain or difficulty swallowing that can feel similar to severe heartburn. This type of infection requires specific antifungal medications and will not improve with standard acid-reducing drugs alone.
Patients receiving radiation therapy to the chest or upper abdomen may experience esophagitis directly from the radiation itself. This irritation is separate from chemotherapy’s chemical effect and often resolves a few weeks after treatment is completed. Recognizing these distinct causes ensures the patient receives the correct treatment plan. Contact a doctor immediately if severe chest pain, difficulty swallowing, or blood in vomit or stool occurs, as these symptoms indicate a potentially serious issue.
Managing and Preventing Heartburn During Treatment
Managing chemotherapy-related heartburn involves a combination of lifestyle adjustments and medication, focusing on reducing acid exposure and protecting the esophageal lining. Dietary modifications are one of the most effective ways to mitigate symptoms. Eating five or six small meals throughout the day, rather than three large ones, helps prevent the stomach from becoming overly full and reduces pressure on the LES.
Patients should avoid common trigger foods, including high-fat or spicy meals, acidic items like citrus fruits and tomatoes, and beverages containing caffeine or alcohol. Remain upright for at least two to three hours after eating, avoiding lying down, bending over, or exercising immediately following a meal. To prevent nighttime reflux, patients can elevate the head of their bed by six to eight inches, using blocks or wedges, which utilizes gravity to keep stomach contents down.
Medication options are typically guided by the oncology team and include several classes of drugs. Over-the-counter antacids, such as calcium carbonate or magnesium-aluminum combinations, provide quick, temporary relief by neutralizing stomach acid. For longer-lasting control, Histamine-2 receptor blockers (H2 blockers), like famotidine, decrease the amount of acid the stomach produces.
Proton Pump Inhibitors (PPIs) are the most powerful acid reducers and are often prescribed for more persistent or severe reflux. Patients should always consult their care team before starting any new medication, as some acid reducers can interfere with the absorption of certain oral chemotherapy drugs.