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The appendix is part of the digestive system, and it is located close to where the large intestine and small intestine come together. The exact function of the appendix is uncertain, but it may play a role in your immune system.
Appendix (or appendiceal) cancer occurs when the appendix's cells mutate and grow out of control, forming a tumor. Tumors can either be malignant or benign. Malignant appendix tumors can spread to other parts of the body, while benign tumors remain relegated to the appendix. Since appendix cancer is rare, all patients with an appendix tumor should have their pathology formally reviewed and seek the advice of doctors who specialize in treating appendix cancer.
The outcome for appendix cancer often depends on tumor size. Tumors less than 2 centimeters are less likely to be malignant and spread. However, larger tumors generally require more aggressive treatment.
Types of appendix cancer
Appendix cancer is classified by the type of cells that form the tumor. The main types are:
Carcinoid tumors: About half of appendix cancers are carcinoid tumors (also called neuroendocrine tumors). These tumors affect neuroendocrine cells that receive signals from the nervous system and release hormones. Most carcinoid tumors are small and slow-growing, and they often can be treated successfully.
Mucinous cystadenoma: These benign (non-cancerous) tumors develop in the lining of the appendix (the epithelium). So long as the appendix remains intact, mucinous cystadenoma will not spread to other organs.
Appendiceal adenocarcinoma: These tumors begin in the epithelium or lining of the appendix. They specifically affect glandular cells, which secrete bodily fluids. There are several categories of adenocarcinoma tumors, summarized below:
- Mucinous adenocarcinoma: The second most common type of appendix cancer is mucinous adenocarcinoma. Mucinous tumors originate in the lining of the appendix, and they are characterized by their secretion of mucin, the gelatinous protein component of mucus.
- Colonic-type adenocarcinoma: These tumors are similar to those of colorectal cancer and cause many of the same symptoms. They tend to appear near the base of the appendix.
- Signet ring cell adenocarcinoma: Though rare, this aggressive type of tumor can occasionally develop in the appendix. When it occurs, the cancer cells produce and store large amounts of mucin, which gives them their characteristic signet ring appearance under the microscope.
Appendix cancer, especially adenocarcinoma type tumors, can sometimes lead to a disease known as pseudomyxoma peritonei (PMP).
PMP is characterized by the presence and growth of mucin-producing tumor cells in the abdomen. The tumor cells may start in the appendix. As the tumor develops and fills with mucus, it may rupture and spread mucus throughout your peritoneal cavity - the space between your internal organs and the inner lining of your abdomen. As mucinous tumor cells grow and accumulate, they press on your other organs. This pressure can impair your body's digestive functions and lead to malnutritiion.
Common symptoms of PMP include increasing abdominal girth, abdominal pain or pressure, a feeling of fullness, and enlarged ovaries (in women).
Anything that increases your chance of getting appendix cancer is a risk factor. They include:
- Age: Appendix cancer is commonly diagnosed in people over 50; it is rare in children
- Smoking tobacco
- Gender: Women are more likely to develop carcinoid tumors than men
- Certain health conditions, such as atrophic gastritis, pernicious anemia or Zollinger-Ellison syndrome, which affect the stomach’s ability to make acid
- Having a family history of multiple endocrine neoplasia type 1 (MEN1) syndrome, a disorder also called endocrine adenomatosis and Wermer syndrome
Not everyone with risk factors gets appendix cancer. However, if you have risk factors, you should discuss them with your doctor.
Learn more about appendix cancer:
Why choose MD Anderson for appendix cancer treatment?
When you are treated in MD Anderson’s Gastrointestinal Center for appendix cancer, some of the nation’s top experts focus on finding the best treatment for you. They work together closely and communicate often to be sure you receive the most advanced personalized care with the least impact on your body.
Appendix Cancer Expertise
Surgery is often the main therapy for cancer of the appendix, and the skill of the surgeon is an important part of your successful treatment. MD Anderson’s surgeons are among the most experienced in the nation in the delicate procedure.
As one of the nation’s most active cancer centers, MD Anderson sees more appendix cancer cases than most oncologists. This gives us an exceptional level of expertise that often gives you higher chances for successful treatment.
Innovation and Support
Because we are one of the nation’s leading research centers, we’re able to offer clinical trials of experimental treatments of groundbreaking drugs and delivery methods for every type and stage of appendix cancer.
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Many cancers can be prevented with lifestyle changes and regular screening.
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