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Appendix Cancer Facts

Appendix cancer is diagnosed in fewer than 1,000 Americans each year.

The appendix is part of the digestive system, and it is located close to where the large intestine and small intestine come together. Tumors in the appendix may be interpreted as malignant (cancer) or benign (not cancer). Given the rarity of this disease, all patients with an appendix tumor should have their pathology formally reviewed and seek the advice of doctors who specialize in treating appendix cancer.

Most cases of appendix cancer are found when a person has surgery for another condition. Almost half are found during surgery for acute appendicitis; others are discovered when an abdominal mass is seen during a CT scan for an unrelated condition.

The outcome for appendix cancer depends a great deal on the size of the tumor. When the tumor is smaller than 2 centimeters, the cancer is less likely to spread. However, when tumors are larger they generally require more aggressive treatment.  

Appendix cancer is classified by the type of cells within the tumor. The main types are:

Carcinoid tumors

About half of appendix cancers are carcinoid tumors. Carcinoid tumors are most often found in women in their 40s. Most carcinoid tumors are small, and they often can be treated successfully.

Non-carcinoid appendix tumors

These tumors begin in the epithelial cells that line the inside of the appendix. Most epithelial cells produce mucin, a gelatinous material. These tumors have a tendency to spread, and the success of treatment depends on several factors.

PMP Cancer (PMP), Pseudomyxoma peritonei

Mucin within the abdomen has few tumor cells, but cells may spread outside the appendix into the abdomen. Adenocarcinoid tumors, also known as goblet cell carcinomas, have characteristics similar to both carcinoid and adenocarcinoma tumors of the appendix. Most patients are diagnosed in their 50s.

Appendix Cancer Risk Factors

Anything that increases your chance of getting appendix cancer is a risk factor. Not everyone with risk factors gets appendix cancer.

Risk factors include:

  • 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.

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