A part of the gastrointestinal (GI) tract, the appendix is a pouch-like tube that is attached to the cecum (the first section of the large intestine or colon) and averages 10 centimeters (cm) in length. Generally thought to have no significant function in the body, the appendix may be a part of the lymphatic, exocrine, or endocrine systems.
Appendix cancer occurs when cells in the appendix become abnormal and multiply without control. These cells form a growth of tissue, called a tumor. A tumor can be benign (noncancerous) or malignant (cancerous, meaning it can spread to other parts of the body).
Types of appendix tumors
There are a variety of tumors that can start in the appendix, including:
Carcinoid tumor. A carcinoid tumor starts in the hormone-producing cells that are normally present in small amounts in almost every organ in the body. A carcinoid tumor arises primarily in the GI tract and lungs, but it also may occur in the pancreas, testicles (men), or ovaries (women). An appendix carcinoid tumor most often occurs at the tip of the appendix and makes up approximately 66% of appendix tumors. This type of tumor usually causes no symptoms until it has spread to other organs, and often goes unnoticed until it is found during an examination or procedure performed for another reason. An appendix carcinoid tumor that remains confined to the area where it started has a high chance of successful treatment with surgery. For more information, see the Cancer.Net Guide to Carcinoid Tumor.
Mucinous cystadenocarcinoma. Mucinous cystadenocarcinoma is the most common noncarcinoid appendix tumor and accounts for approximately 20% of appendix cancer cases. This type of tumor produces a jelly-like substance called mucin that fills the abdominal cavity and can cause abdominal pain, bloating, and changes in bowel function.
Colonic-type adenocarcinoma. Colonic-type adenocarcinoma accounts for approximately 10% of appendix tumors and usually occurs at the base of the appendix. This type of tumor looks and behaves similarly to the most common type of colorectal cancer. It often goes unnoticed, and diagnosis is often made during or after surgery for appendicitis (inflammation of the appendix that can cause abdominal pain, loss of appetite, nausea, vomiting, constipation or diarrhea, inability to pass gas, a low fever that begins after other symptoms, or abdominal swelling).
Signet-ring cell adenocarcinoma. Signet-ring cell adenocarcinoma (so called because under the microscope, the cell looks like it has a signet ring inside it) is very rare and considered to be more aggressive and more difficult to treat than other adenocarcinomas. This type of tumor usually occurs in the stomach or colon, and can cause appendicitis when it develops in the appendix.
Paraganglioma. Paraganglioma is a rare tumor that develops from cells of the paraganglia, a collection of cells that come from nerve tissue that remains in small deposits after fetal development, and is found near the adrenal glands and some blood vessels and nerves. This type of tumor is usually considered benign and is often successfully treated with the complete surgical removal of the tumor. Paraganglioma is very rare outside of the head and neck region.
Statistics
Primary appendix cancer (cancer that starts in the appendix) is uncommon, and statistics for appendix cancer are typically included as part of colorectal cancer data. It is estimated that about 1% of colorectal cancer cases in the United States are primary appendix cancer, affecting about 1,500 people each year.
The overall 5-year relative survival rate (percentage of patients who survive at least five years after the cancer is detected, excluding those who die from other diseases) of patients with appendix cancer varies depending on several factors, including the type of tumor.
Cancer survival statistics should be interpreted with caution. It is not possible to tell a person how long he or she will live with appendix cancer. Because the survival statistics are measured in five-year (or sometimes one-year) intervals, they may not represent advances made in the treatment or diagnosis of this cancer.
A risk factor is anything that increases a person’s chance of developing cancer. Some risk factors can be controlled, such as smoking, and some cannot be controlled, such as age and family history. Although risk factors can influence the development of cancer, most do not directly cause cancer. Some people with several risk factors never develop cancer, while others with no known risk factors do. However, knowing your risk factors and communicating them to your doctor may help you make more informed lifestyle and health-care choices.
The cause of appendix cancer is unknown, and no avoidable risk factors have been identified. The following factor may raise a person’s risk of developing appendix cancer:
Age. For a carcinoid tumor of the appendix, the average age at diagnosis is approximately 40. Carcinoid tumors are rare in children.
People with appendix cancer may experience the following symptoms. Sometimes, people with appendix cancer do not show any of these symptoms. Or, these symptoms may be caused by a medical condition that is not cancer. If you are concerned about a symptom on this list, please talk with your doctor.
Appendicitis
Ascites (fluid in the abdomen)
Bloating
Pain in the abdomen or pelvis area
Increased girth (size of the waistline), with or without a protrusion of the navel (bellybutton)
Doctors use many tests to diagnose cancer and determine if it has metastasized (spread). Some tests may also determine which treatments may be the most effective. For most types of cancer, a biopsy is the only way to make a definitive diagnosis of cancer. If a biopsy is not possible, the doctor may suggest other tests that will help make a diagnosis. Imaging tests may be used to find out whether the cancer has metastasized. Your doctor may consider these factors when choosing a diagnostic test:
Age and medical condition
The type of cancer suspected
Severity of symptoms
Previous test results
In addition to a physical exam, the following tests may be used to diagnose appendix cancer:
Biopsy. A biopsy is the removal of a small amount of tissue for examination under a microscope. Other tests can suggest that cancer is present, but only a biopsy can make a definite diagnosis. The sample removed from the biopsy is analyzed by a pathologist (a doctor who specializes in interpreting laboratory tests and evaluating cells, tissues, and organs to diagnose disease).
However, most often, appendix cancer is found unexpectedly during or after abdominal surgery. If cancer is suspected at the time of surgery, the doctor will remove a portion of the colon and surrounding tissue (called a margin) for examination. Often, a patient will have an appendectomy (surgical removal of the appendix) for what is thought to be appendicitis, and the cancer is diagnosed after the pathologist has processed and reviewed the tissue under the microscope. In that case, another surgery is usually recommended to take another margin of normal tissue around the area where the tumor began.
Imaging tests
Computed tomography (CT or CAT) scan.A CT scan creates a three-dimensional picture of the inside of the body with an x-ray machine. A computer then combines these images into a detailed, cross-sectional view that shows any abnormalities or tumors. Sometimes, a contrast medium (a special dye) is injected into a patient’s vein to provide better detail.
Magnetic resonance imaging (MRI). An MRI uses magnetic fields, not x-rays, to produce detailed images of the body. A contrast medium may be injected into a patient’s vein to create a clearer picture.
Ultrasound. An ultrasound uses sound waves to create a picture of the internal organs.
Radionuclide scanning (OctreoScan). A small amount of a radioactive, hormone-like substance that is attracted to a carcinoid tumor is injected into a vein. A special camera is then used to show where the radioactive substance accumulates. This procedure is useful in detecting spread of a carcinoid tumor, especially to the liver.
Staging is a way of describing a cancer, such as where it is located, if or where it has spread, and if it is affecting the functions of other organs in the body. Doctors use diagnostic tests to determine the cancer's stage, so staging may not be complete until all of the tests are finished. Knowing the stage helps the doctor to decide what kind of treatment is best and can help predict a patient's prognosis (chance of recovery). There are different stage descriptions for different types of cancer.
There is no standard system for staging appendix cancer. However, many doctors classify an appendix tumor into three general stages:
Localized spread. The tumor has not spread beyond the wall of the primary organ, such as the appendix, stomach, or intestine.
Regional spread. The tumor has spread through the wall of the primary organ and involves nearby tissue, such as fat, muscle, or lymph nodes.
Distant spread. The tumor has spread to tissue or organs far away from the primary organ, such as other areas of the abdomen, liver, bones, or lungs.
Recurrent. Recurrent cancer is cancer that comes back after treatment.
Tumor grades. Doctors may also use the term "grade," which describes how much the tumor appears like normal tissue. The grade of a cancer can help the doctor predict how quickly the cancer might grow. In cancer that resembles normal tissue, doctors can clearly see different types of cells grouped together (called well differentiated). In a higher-grade cancer, cancer cells usually look less like normal cells, or "wilder" (called poorly differentiated or undifferentiated). In general, a patient with a more differentiated tumor has a better prognosis.
GX: The tumor grade cannot be identified.
G1: The tumor cells are well differentiated.
G2: The tumor cells are moderately differentiated.
The treatment of appendix cancer depends on the size and location of the tumor, whether the cancer has spread, and the patient’s overall health. In many cases, a team of doctors will work with the patient to determine the best treatment plan.
This section outlines treatments that are the standard of care (the best treatments available) for this specific type of cancer. Patients are also encouraged to consider clinical trials when making treatment plan decisions. A clinical trial is a research study to test a new treatment to prove it is safe, effective, and possibly better than standard treatment. Your doctor can help you review all treatment options. For more information, visit the Clinical Trials section.
Surgery
Surgery is the most common treatment for appendix cancer. Most often, appendix cancer is low grade and therefore slow growing. Often it can be successfully treated with surgery. For advanced appendix cancer, debulking surgery (to remove as much tumor as possible) may be performed.
An appendectomy is usually the only treatment needed for an appendix tumor smaller than 1.5 cm. For a tumor larger than 2 cm, the removal of about one-third of the colon next to the appendix, along with nearby blood vessels and lymph nodes, is often needed.
There is some controversy about the extent of surgery that is necessary in patients with slow growing, low grade cancer. Some surgeons recommend aggressive surgery that includes the removal of the peritoneum (the lining of the abdomen) to remove as much of the cancer as possible. In patients with a very slow growing tumor, such surgery can be effective in removing the majority of the cancer cells. Patients should see a specialist with expertise in this type of procedure, as it is a difficult operation. Sometimes, chemotherapy (see below) will be used after surgery to destroy any remaining cancer cells.
A right hemicolectomy may be used for advanced appendix cancer. In this procedure, approximately half of the large intestine is removed. Even though a large amount of the large intestine is removed, the operation usually does not result in the need for a colostomy or stoma (an opening in the abdomen through which the bowel contents are emptied into a bag).
In cases where appendix cancer is discovered unexpectedly after an appendectomy was performed for what was thought to have been appendicitis, a second operation to remove more tissue (using similar surgical techniques to those described above) is often recommended.
In cases where the tumor produces mucous, much of the bulk of the abnormal tissue is often not cancer, but is due to accumulation of the mucous. The mucous looks like jelly, and the condition is often referred to as “jelly belly.” Removing the mucous from the abdomen can often relieve a patient’s symptoms of bloating.
Chemotherapy
Chemotherapy is the use of drugs to kill cancer cells. Systemic chemotherapy is delivered through the bloodstream, targeting cancer cells throughout the body. The most common type of chemotherapy used in the treatment of appendix cancer is intraperitoneal chemotherapy, which is chemotherapy that is given directly into the abdominal cavity. For appendix cancer, chemotherapy is most often used soon after surgery when cancer is found outside of the appendix region. Most surgeons will try to remove as much of the tumor as possible and will insert a tube in the abdomen through which chemotherapy can be administered after the operation. In some cases, the chemotherapy is warmed up to above body temperature to increase its ability to penetrate the tissue that may be lined with tumor cells; this is called intraperitoneal hyperthermic chemotherapy. Once chemotherapy is completed, the tube is removed, generally without the need for another operation.
The side effects of chemotherapy depend on the individual and the dose used, but can include fatigue, risk of infection, nausea and vomiting, loss of appetite, and diarrhea. These side effects usually go away when treatment is finished.
The medications used to treat cancer are continually being evaluated. Talking with your doctor is often the best way to learn about the medications prescribed for you, their purpose, and their potential side effects or interactions with other medications. Learn more about your prescriptions through Cancer.Net's Drug Information Resources, which provides links to searchable drug databases.
Radiation therapy
Radiation therapy is the use of high-energy x-rays or other particles to kill cancer cells. Radiation therapy is rarely used in the treatment of appendix cancer. In certain cases, a form of radiation called P32 may be recommended. In this procedure, radioactive phosphorus is dissolved in a liquid and placed inside the body after surgery through a tube inserted in the abdomen (see above). P32 delivers strong radiation therapy to a local area; because the radioactivity disappears quickly (within a few hours), there is no need to remove the substance from the abdomen after treatment.
Doctors and scientists are always looking for better ways to treat patients with appendix cancer. A clinical trial is a way to test a new treatment to prove that it is safe, effective, and possibly better than a standard treatment. Patients who participate in clinical trials are among the first to receive new treatments before they are widely available. However, there is no guarantee that the new treatment will be safe, effective, or better than a standard treatment.
Patients decide to participate in clinical trials for many reasons. For some patients, a clinical trial is the best treatment option available. Because standard treatments are not perfect, patients are often willing to face the added uncertainty of a clinical trial in the hope of a better result. Other patients volunteer for clinical trials because they know that finding new drugs and other therapies is the only way to make progress in treating appendix cancer. Even if they do not benefit directly from the clinical trial, their participation may benefit future patients with appendix cancer.
To join a clinical trial, patients must complete a learning process known as informed consent. During informed consent, the doctor should list all of the patient’s options, so the person understands how the new treatment differs from the standard treatment. The doctor must also list all of the risks of the new treatment, which may or may not be different from the risks of standard treatment. Finally, the doctor must explain what will be required of each patient in order to participate in the clinical trial, including the number of doctor visits, tests, and the schedule of treatment. Learn more about clinical trials, including patient safety, phases of a clinical trial, deciding to participate in a clinical trial, questions to ask the research team, and links to find cancer clinical trials.
Cancer and its treatment can cause a variety of side effects. However, doctors have made major strides in recent years in reducing pain, nausea and vomiting, and other physical side effects of cancer treatments. Many treatments used today are less intensive but as effective as treatments used in the past. Doctors also have many ways to provide relief to patients when such side effects do occur.
Fear of treatment side effects is common after a diagnosis of cancer, but it may be helpful to know that preventing and controlling side effects is a major focus of your health-care team. Before treatment begins, talk with your doctor about possible side effects of the specific treatments you will be receiving. The specific side effects that can occur depend on a variety of factors, including the type of cancer, its location, the individual treatment plan (including the length and dosage of treatment), and the person’s overall health.
Ask your doctor which side effects are most likely to happen (and which are not), when side effects are likely to occur, and how they will be addressed by the health-care team if they do happen. Also, be sure to communicate with your doctor about side effects you experience during and after treatment. For more information on the most common side effects of cancer and different treatments, along with ways to prevent or control them, visit Cancer.Net’ s section on Managing Side Effects.
In addition to physical side effects, there may be psychosocial (emotional and social) effects as well. Learn more about the importance of addressing these needs in Cancer.Net’s section on Caring for the Whole Patient.
For more information on late effects or long-term side effects, please read the After Treatment section or talk with your doctor.
After treatment for appendix cancer ends, talk with your doctor about developing a follow-up care plan. This plan may include regular physical examinations and/or medical tests to monitor your recovery for the coming months and years. People treated for appendix cancer will generally need to follow up with an oncologist (a doctor who specializes in cancer), surgeon, or internal medicine specialist to monitor any symptoms of abdominal recurrence, such as pain, nausea, blood in the stool, severe bloating and cramping; CT or MRI scans may be recommended as part of follow-up care.
People recovering from appendix cancer are encouraged to follow established guidelines for good health, such as maintaining a healthy weight, not smoking, eating a balanced diet, and having recommended cancer screening tests. Talk with your doctor to develop a plan that is best for your needs. Moderate physical activity can help rebuild your strength and energy level. Your doctor can help you create an appropriate exercise plan based upon your needs, physical abilities, and fitness level. Learn more about Healthy Living After Cancer.
Research for more advanced diagnostic procedures and treatment for appendix cancer is ongoing, but is hampered by the rare nature of the disease. Always discuss all diagnostic and treatment options with your doctor.
Regular communication with your doctor is important in making informed decisions about your health care. Consider asking the following questions of your doctor:
What type of appendix cancer do I have?
Can you explain my pathology report to me?
Is the cancer considered to be localized, regional, or advanced? What does this mean?
How often do you treat people with appendix cancer?
What are my treatment options?
What clinical trials are open to me?
What treatment option do you recommend? Why?
What is my prognosis?
Can surgery be done to remove all of the cancer?
Can surgery be done to debulk the cancer? How will this help me?
How experienced is the surgeon with this type of operation?
Do you recommend chemotherapy after surgery?
What are the possible side effects of this treatment, both in the short term and the long term?
How will this treatment affect my daily life? Will I be able to work, exercise, and perform my usual activities?
What follow-up tests will I need, and how often will I need them?
What support services are available to me? To my family?
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