The appendix is a thin tubular structure located in the lower right portion of your abdomen.
The overall purpose of the appendix is not fully known. But research suggests it is home to healthy gut bacteria and it plays a role in your immune system. Many people get their appendix removed when it becomes inflamed — a condition known as appendicitis.
If healthy cells of the appendix change into abnormal cancerous cells, the result is appendix cancer.
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Types of Appendix Cancer
Appendix cancers are rare, affecting about 2,500 to 5,000 people each year in the United States.
“It’s not a very common problem,” says M. Haroon A. Choudry, MD, a surgical oncologist at UPMC Hillman Cancer Center. “But these tumors can be difficult to treat, especially when they are discovered at an advanced stage.”
There are two major types of tumors:
- Epithelial tumors: These start in the cells along the inner lining (also known as mucosa) of the appendix. They include:
- Mucinous neoplasms and adenocarcinomas: The most common type, they produce mucus (a jelly-like substance) and often spread into the abdominal cavity.
- Goblet cell adenocarcinomas (adenocarcinoids): Usually more aggressive, they are more common in patients over the age of 50.
- Non-mucinous (colonic-type) adenocarcinomas: The second most common type, they are similar to regular colorectal cancers.
- Signet-ring cell adenocarcinoma: A rare, aggressive cancer, it occurs more often in the stomach or colon but can form in the appendix.
- Non-epithelial tumors: These start in cells found deeper in the appendix wall.
- Neuroendocrine tumors, also known as carcinoids, can produce hormones.
Dr. Choudry says that mucinous appendix tumors can be classified as low-grade and high-grade. Low-grade tumors are less likely to invade other organs. High-grade tumors are aggressive and harder to treat.
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What Causes Appendix Cancer?
The cause of appendix cancer is unknown. Some people may be at higher risk due to lifestyle, family history, and other factors including:
- Age: Appendix cancer is most common in people age 40 and older
- Gender: Women more frequently get appendix cancer than men, though not by a large amount
- Smoking: Smokers are more likely to get appendix cancer than non-smokers
- Family history: People with a family history of appendix cancer or other conditions, like multiple endocrine neoplasia type 1 (MEN1), are more at risk
- Medical history: Certain conditions involving the stomach’s ability to make acid may put you at a higher risk. These can include atrophic gastritis, pernicious anemia, and Zollinger-Ellison syndrome.
Symptoms of Appendix Cancer
There are few symptoms in the early stages of appendix cancer. The most common symptom of appendix cancer that hasn’t spread is appendicitis, which comes with lower right abdominal pain.
Because the appendix has a thin wall, tumors can break through and spread throughout the abdominal cavity. When that happens, it can cause symptoms such as:
- Abdominal pain
- Changes in bowel habits
- Decreased appetite
- Distended abdomen
- Ovarian masses
- Weight loss/gain
A disease called pseudomyxoma peritonei (PMP) can develop if a mucinous tumor spreads into the abdominal cavity. The mucus that the cancer cells produce builds up in the abdominal cavity. PMP can cause a distended abdomen, weight loss or gain, abdominal pain, and a change in bowel habits.
Because appendix cancer doesn’t have many early symptoms, it can be difficult to diagnose at early stages. “If it doesn’t present as acute appendicitis or if patients only have vague abdominal complaints, there can be a delay in the diagnosis of these tumors,” says Dr. Choudry . “In these situations, the disease usually gets diagnosed when it has already spread into the abdominal cavity.”
Imaging tests – MRIs, CT scans, and ultrasounds – can find appendix tumors. Doctors may use a biopsy to diagnose it.
Treatment for Appendix Cancer
Treatment depends on factors like the type of appendix cancer, grade of the tumor, and stage of the cancer.
“For mucinous appendix tumors, the two most important considerations for treatment include whether the cancer has ruptured and what the grade of the tumor is,” says Dr. Choudry.
Surgery is the most common treatment for appendix tumors that have not spread. Doctors may remove just the appendix or also may take part of the colon as well as nearby lymph nodes and blood vessels.
For epithelial appendix cancers that have spread within the abdominal cavity, doctors often combine surgery with chemotherapy delivered directly into the abdomen. This involves surgery to remove all visible tumors in the abdomen followed by a specialized procedure called hyperthermic intraperitoneal chemoperfusion (HIPEC) to deliver heated chemotherapy directly into the abdominal cavity.
The prognosis for appendix cancer depends on the specific type, tumor grade, how far it has spread, and the available treatment options.
For more information, contact UPMC Hillman Cancer Center at 1-866-923-1655.
UPMC Hillman Cancer Center provides world-class cancer care, from diagnosis to treatment, to help you in your cancer battle. We are the only comprehensive cancer center in our region, as designated by the National Cancer Institute. We have more than 70 locations throughout Pennsylvania, Ohio, New York, and Maryland, with more than 200 oncologists. Our internationally renowned research team is striving to find new advances in prevention, detection, and treatment.