Digestive Problems

Digestive Problems

Reviewed By:
Mark Oren, M.D., FACP


A symptom is the way the body communicates the presence of a disease, illness or injury. Signs also may be an indication that part of the body is not functioning properly, but they are more narrowly defined as observations made by a physician or other qualified medical professional.

Digestive problems are among the signs and symptoms of many types of cancer, such as cancers of the mouth, esophagus, throat or gastrointestinal tract. Digestive problems may occur as a side effect caused by cancer treatments, such as chemotherapy and radiation therapy.

Some of the most common digestive problems associated with cancer and its treatments include, but are not limited to nausea, vomiting, diarrhea and constipation. It is important to remember that numerous conditions, most unrelated to cancer, can cause digestive difficulties.  Typically, digestive problems are temporary and resolve on their own or with minimal intervention.

However, digestive problems can be a sign of a more serious disease, such as cancer. To determine the possible cause of the digestive problems, physicians obtain a medical history, review the patient’s symptoms and conduct a physical examination. Patients may be seen by their regular physician or if necessary, by a specialist such as a gastroenterologist, who is an expert in the problems of the digestive (gastrointestinal) tract. The treatment of digestive problems can be established once the underlying cause has been determined.

About digestive problems

Digestive problems are often symptoms of mild or even temporary conditions. Problems that are chronic or those that appear to get worse or intensify over time should be evaluated by a physician. These symptoms may be early signs of a more serious condition, such as an ulcer or cancer. In addition, digestive problems may be a result of cancer treatment (e.g., surgery, chemotherapy, radiation therapy).

Digestion is the process in which the body converts food into simple substances for growth, energy and cell repair. The purpose of the digestive system is to break down food into nutrients that the body can absorb and use for fuel. This complex system is made up of abdominal organs, including the alimentary canal, also known as the digestive tract, that starts at the mouth and continues for nearly 30 feet (approximately 9 meters) before it reaches the anus, where waste products are eliminated.

Some of the most common digestive problems associated cancer and other medical conditions include:

  • Nausea
  • Vomiting
  • Diarrhea or constipation
  • Abdominal cramps or pain
  • Abdominal bloating
  • Changes in bladder or bowel habits
  • Difficulty swallowing or digesting food
  • Heartburn or gastric difficulties

Many cancers present few, if any, signs or symptoms, especially in the early stages of the disease. Subsequent development of signs or symptoms depends on the location, type and stage of the cancer. As the cancer grows, it may begin to place pressure on surrounding organs, tissues, blood vessels, nerves or other structures. This pressure, as well as other factors, can cause the signs and symptoms associated with cancer in various regions of the body.

It is important to note that digestive problems do not necessarily indicate the presence of cancer. Most common digestive problems are caused by other, less serious conditions, such as minor gastrointestinal problems, infections or irritable bowel syndrome (IBS). The final determination of the underlying cause of digestive problems should be made by a gastroenterologist (a physician who specializes in diseases of the digestive tract). If cancer is diagnosed by the gastroenterologist, the patient will be referred to a medical oncologist for further testing and treatment planning.

Potential causes of digestive problems

Cancer can develop almost anywhere in the digestive tract. The digestive tract (alimentary canal) starts at the mouth and continues for nearly 30 feet (approximately 9 meters) before it reaches the anus, where waste products are eliminated. It is a complex system of organs that help the body digest food and eliminate waste.  If cancers that impact the digestive tract are detected and treated in their earliest stages, they are highly curable in most cases. Some cancers commonly associated with digestive problems include:

  • Oral and throat cancer. The early signs of oral and throat cancer will develop mainly in the soft tissues of the mouth. Most oral cancers develop on the tongue, on the floor of the mouth, inside the cheek, on the gums or on the roof of the mouth. Symptoms of these cancers can include:

    • Sores in the mouth that do not heal or increase in size

    • Lumps or colored patches inside the mouth

    • Thickening of the cheek or other mouth tissues

    • Chewing or swallowing difficulties (dysphagia)

    • Numbness or difficulties moving the tongue

    • Pain or swelling in the jaw

    • Persistent sore throat or  the feeling of something caught in the throat
  • Esophageal cancer. Some of the signs and symptoms of esophageal cancer include dysphagia (difficulty swallowing), severe and unintentional weight loss, pain or burning of the throat as food travels through the esophagus.  In addition, an individual may experience pain in the chest or between the shoulder blades, hoarseness, chronic cough or coughing up blood. Small tumors rarely cause symptoms until the disease progresses.

  • Stomach (gastric) cancer. At its earliest stages, microscopic internal bleeding is a possible sign of stomach cancer. This sign can be detected only by looking for trace amounts of blood in the stool using certain tests. As the disease progresses, other signs and symptoms may include abdominal discomfort that is not relieved with antacids and may be aggravated by eating. Patients may also exhibit bloating of the stomach or vomiting after meals, vomiting of blood or stools that are black or tarry.

  • Gallbladder cancer. Some of the signs and symptoms of gallbladder cancer include abdominal pain, nausea, vomiting, loss of appetite and weight loss.

  • Liver cancer. There are very few signs or symptoms of liver cancer in its early stages. As the disease progresses, it may cause noticeable symptoms such as loss of appetite or weight, abdominal pain, nausea and vomiting. Patients may also exhibit an enlarged liver, abdominal swelling or decreased liver function as detected by tests.

  • Pancreatic cancer. There are very few signs or symptoms of pancreatic cancer in its early stages, which often leads to a late diagnosis when the disease is far less treatable. For this reason, it is one of the deadliest types of cancer. As the disease progresses, pancreatic cancer can cause loss of appetite, significant weight loss, nausea and vomiting. Digestive problems are common with this cancer due to the challenges of digesting certain foods, particularly those high in fat.
  • Bile duct cancer (cholangiocarcinoma). Some of the signs and symptoms of bile duct cancer include an enlarged gallbladder, coffee-colored urine, loss of appetite, weight loss and white or clay-colored stools.

  • Colorectal cancer. Colon cancer originates in the large intestine (colon) and rectal cancer starts in the rectum. Since these two types of cancers share common features, they are sometimes combined as colorectal cancer. This type of cancer does not produce many signs or symptoms of disease in its earliest stages. When symptoms do appear, they  depend on the size and location of the tumor, as well as the stage of the cancer. Generally, symptoms of colorectal cancer include a change in bowel habits (such as diarrhea or constipation), pencil-thin stools, rectal bleeding or blood in the stool, or cramping in the lower stomach. Many patients may also have an urge to have a bowel movement when there is no need to have one, painful gas or unexplained weight loss.

  • Anal cancer. The anus is located at the end of the large intestine (bowel). This opening allows stools to be passed during a bowel movement. Cancer can develop in the portion of the anus that is inside the body or the part that is outside the body. Symptoms of this type of cancer are similar to several of those found with colorectal cancer.

Approximately 50 percent of gastrointestinal carcinoid tumors (hormone-secreting tumors that develop in the lining of the gastrointestinal tract) are diagnosed as a result of symptoms, according to the American Cancer Society (ACS). The most common symptom is stomach pain, which can continue for years until the tumor is found. Carcinoid tumors can cause a wide array of symptoms, including intestinal bleeding, diarrhea and flushing of the skin.

There are several other cancers that are not related to the digestive tract but nonetheless may cause digestive problems as they progress. These include:

  • Metastatic breast cancer. When breast cancer spreads (metastasizes) to other sites in the body, it can cause a variety of digestive problems. Bloating, pain and vaginal bleeding are symptoms of metastases to the ovaries, whereas abdominal pain and digestive problems may signal metastases to the liver or stomach.
  • Endometrial cancer. Cancer of the lining of the uterus (womb) may produce pelvic pain, unusual bleeding, spotting and weight loss in patients.

  • Ovarian cancer. Ovarian cancer is often diagnosed in its later stages because two of the major symptoms – indigestion and abdominal swelling – are common signs of many conditions other than cancer. Individuals often attribute the digestive problems to less serious conditions, leading to a late diagnosis of ovarian cancer.

Additionally, treatments for cancer can also cause digestive problems in some individuals:

  • Chemotherapy.Chemotherapy is a method of treating various cancers using powerful drugs that attack cancer cells and help prevent the spread of the disease. This treatment may cause the following digestive problems:
    • Loss of appetite and weight loss
    • Nausea and vomiting
    • Diarrhea or constipation
    • Sensitivity to smell and taste
    • Difficulty with digestion
    • Mouth or lip sores

    Many of the side effects of chemotherapy may be alleviated with medications. A patient’s cancer care team can help determine the best ways to combat the digestive problems experienced from treatment.

  • Radiation therapy.Radiation therapy uses a specific type of precise x-rays to kill or shrink cancer cells. When directed at the chest or abdomen, radiation therapy may cause swelling or inflammation of the esophagus or intestines, which, in turn, can lead to nausea, vomiting and/or diarrhea. Antacids can help, as can dietary modifications (e.g. avoiding spicy, fried or high-fiber foods). In severe cases, dehydration may be severe enough to require administration of intravenous fluids.

From time to time, most people will experience some type of digestive problem, particularly diarrhea or constipation. Many common digestive problems can be caused by conditions that require medical attention, but are less serious in nature than cancer. These may include:

  • Gastrointestinal infections. These infections can be a result of exposure to viruses, bacteria or possibly intestinal parasites.

  • Appendicitis. Abdominal pain, fever, loss of appetite and vomiting are all symptoms of inflammation of the appendix. In advanced cases, the appendix may need to be removed immediately to avoid rupture and serious medical complications.

  • Gastritis and peptic ulcers. Strong acids produced by the stomach can sometimes irritate the stomach and duodenum (the first part of the small intestine).Left untreated, ulcers can cause damage to the digestive tract and organs.

  • Inflammatory bowel disease. This chronic condition is an inflammation of the intestines.

  • Celiac disease. Some people are unable to tolerate a protein called gluten, which is found in wheat, rye and barley and a wide range of processed foods. Some of the most common digestive problems associated with this condition include abdominal cramping, abdominal distention, constipation, diarrhea, excessive gas or steatorrhea (stools that are fatty and thus float instead of sinking).

  • Irritable bowel syndrome (IBS). This common intestinal disorder causes abdominal cramping, bloating, constipation and diarrhea.

Diagnosing digestive problems

In most cases digestive problems are temporary or are caused by mild conditions. However, digestive problems may also be a sign of a more serious disease, such as an ulcer or cancer. To diagnose the medical condition causing digestive problems, individuals must be evaluated by a qualified physician.  

It is important to seek medical advice if any condition persists over a period of time or seems to be getting worse. A medical history and complete physical examination will most likely be the first steps in diagnosing the problem. The physician will focus on the areas of concern based on the patient’s complaints, signs and symptoms. Certain tests may be ordered to further evaluate the condition, including:

  • X-rays. An x-ray is a painless test in which an image is created of part of the body by using low doses of electromagnetic radiation. X-rays are often used to help detect and diagnose a number of conditions. They may detect cancerous growths and may determine whether the cancer has spread to other areas of the body. Visualization of the gastrointestinal tract requires administration of barium or an iodine-based dye. The patient may drink a special fluid containing the contrast material or it may be provided by a special enema to highlight the lower intestinal tract. Depending upon a physician’s evaluation of an x-ray image, further tests may be ordered.

  • Ultrasound. An ultrasound test sends and receives high-frequency sound waves to create images of internal organs or tissues. Sound waves pass through the tissues of the area being examined. These sound waves are recorded and displayed on a computer screen or television-type monitor. Ultrasound may be used to diagnose certain types of cancer. It creates images of soft tissue organs, such as the gall bladder, liver, heart, kidney and female reproductive organs. This procedure is especially useful in diagnosing cancer when a tumor is located in soft tissue and it is unclear whether an abnormality is a cyst (sac of fluid) or a solid mass.

  • Stool testing. Also known as a fecal occult blood test  (FOBT), testing involves the collection of stool samples from a patient to aid in the diagnosis digestive or reproductive cancers. The physician may recommend that the stool samples be collected over a period of days since blood in the stool from colon cancer may only appear from time to time rather than with every bowel movement. These tests can be administered in a physician’s office or through the use of an at-home kit.
  • Colonoscopy. This is an examination of the rectum and entire colon (large intestine) with a long tube and camera. A colonoscopy may be performed to screen for colorectal cancer but is also useful to screen for and diagnose other abnormalities, such as inflammatory digestive diseases.  The examination is done with a lighted instrument called a colonoscope that is inserted into a patient’s rectum. It is the most definitive test for detecting abnormalities in the colon, including precancerous and cancerous (malignant) growths. A sigmoidoscopy also may be completed but this test only evaluates the lower end of the colon rather than the entire tract.

Treatment and prevention

Treatment and prevention of digestive problems depends almost entirely on the root cause. For example, many individuals experience digestive problems as a result of radiation therapy to certain areas of the body. Radiation in the chest or abdomen may result in swelling or inflammation of the esophagus or intestines. This can cause dysphagia, as well as nausea, vomiting or diarrhea. Antacids can help reduce digestive discomfort, as can dietary modifications (e.g. avoiding spicy, fried or high-fiber foods).

Many cancer patients can experience digestive problems as a result of chemotherapy, however, the benefits of the treatment outweigh the possible accompanying problems. Although there may be no way to prevent the digestive problems, the patient’s physician may be able to make adjustments to lessen the complications. These problems may be due to the specific drugs used in treatment, the schedule or associated factors. A patient’s medical oncologist as well as other members of the cancer care team can determine  the best ways to possibly reduce digestive problems from treatment.

In severe cases, a patient may develop dehydration, requiring administration of intravenous fluids. Patients also may have difficult eating due to associated difficulties from treatment. For example, inflammation of the mouth lining (mucositis) may occur with radiation to the head and neck area. Dryness and lost of taste in the mouth may occur, and can be permanent in the worst cases. These problems may result in decreased intake and poor nutritional support. Patients may be able to use various medications to help with pain or to increase saliva production. Keeping the mouth clean can help reduce the effect of infection and further problems.

In addition, the patient may be able to tolerate supplemental nutrition (e.g., protein drinks) better than eating foods. A dietitian can offer recommendations to help a patient maintain nutrition while dealing with oral and digestive problems from cancer treatments.

Changes in diet, laxatives and stool softeners can also help relieve constipation that may result from treatments. In addition, there are various medicines that can help control abdominal cramping and diarrhea. As with all medications, they should not be taken without consulting a physician. This is particularly important for cancer patients as certain medications can affect their cancer treatments. In addition, enemas should not be taken with physician consultation.

Chemotherapy-related digestive problems

Many patients have reported severe nausea and vomiting while undergoing chemotherapy treatments. However, many new antinausea drugs have made these symptoms much less common and severe than they were in the past. Different drugs work for different people, and sometimes it is necessary to take more than one medication to obtain relief.

Some drugs used in chemotherapy can cause sores in the mouth (stomatitis) and the throat (mucositis). Initially, the lining of the mouth may appear pale and dry. Later, the mouth, gums and throat may become sore, red and inflamed. The tongue may swell or become coated, leading to difficulty in swallowing (dysphagia), eating or talking. Patients who do not eat well after beginning treatments are most vulnerable to getting sores, which can bleed, ulcerate and become infected. Various medicines can treat mouth sores that may develop. The patient may be referred to a speech-language pathologist to help with the swallowing and communication problems. A dietitian also may be recommended to help with diet planning and nutritional support.

If chemotherapy damages normal cells in the intestine, diarrhea can result. Patients should consult a physician if they have diarrhea that lasts more than 24 hours or that is accompanied by pain and cramping. Intravenous fluids may be necessary to replace water and nutrients that have been lost to diarrhea. Medicines may be prescribed to treat the diarrhea. Over-the-counter medications should not be used unless approved by a physician.

Chemotherapy can also cause constipation, especially in patients who are less active or do not consume enough fluid or fiber. Other factors that may increase the risk of constipation include prolonged bed rest and depression. A patient’s cancer care team will work together to determine the best course of action to treat digestive problems related to chemotherapy and other cancer treatments.

Questions for your doctor

Preparing questions in advance can help patients have more meaningful discussions with their physicians regarding their conditions. Patients may wish to ask their doctor the following questions about digestive problems:

  1. What is the likely cause of my digestive problems?
  2. Are these symptoms an indication of a specific cancer?
  3. What tests can be used to help determine the cause of my problems?
  4. What digestive problems are likely to occur with my cancer diagnosis?
  5. What type of problems can I expect from my cancer treatments?
  6. How long can I expect to experience digestive problems with my cancer?
  7. What can be done to lessen my digestive problems?
  8. What are the signs that my problems are becoming more serious?
  9. What symptoms indicate a medical emergency?
  10. What will be done if I am unable to eat or drink during my treatments?
  11. Can you refer me to a dietitian to help me with my meal planning?
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