What is appendiceal cancer?
Appendiceal cancer is a type of cancer that grows from cells that make up the appendix. The appendix is a small pouch of tissue in the abdomen. It is part of the intestines and colon, which absorb nutrients and remove waste from the body. We do not know what the appendix does, but it may help the immune system. There are two main types of appendiceal cancer: epithelial appendiceal cancer and neuroendocrine appendiceal cancer.
Epithelial appendiceal cancer grows from cells that make up the lining of the appendix. It may also be called adenocarcinoma. These cells help make a jelly-like substance called mucin. Mucin protects the lining of the stomach, intestines, and appendix. Most epithelial appendiceal cancers can lead to a build-up of mucin, which can cause the appendix to rupture. When mucin from the appendix builds up in the abdomen, it causes a condition called pseudomyxoma peritonei, or PMP.
Mucinous neoplasms are a rare and complex type of epithelial appendiceal cancer. Depending on how the cells look under a microscope they may be low grade (LAMN) or high grade (HAMN) and may spread to other parts of the body.
Neuroendocrine tumors of the appendix, grow from cells called enterochromaffin cells (ECs). ECs make chemicals involved in digestion and movement in the intestines. Neuroendocrine tumors of the appendix are the most common type of appendiceal cancer. They are also called carcinoid tumors.
Appendiceal cancer can spread to different parts of the abdomen directly from the appendix, usually when it ruptures. Less often, appendiceal cancer can spread through lymph nodes to areas outside the abdomen.
How common is appendiceal cancer?
Appendiceal cancer is very rare. In the US, it has been thought to affect about 1 or 2 people per 1 million per year. However, recent studies show that appendiceal cancer is becoming more common. It is more common in people between the ages of 50 and 55 years old, but can happen at any age.
How is appendiceal cancer diagnosed?
Many people with appendiceal cancer do not have symptoms when the cancer first starts. Later, when the tumor gets larger, symptoms can include:
- Feeling bloated or growing abdominal size
- A mass in the abdomen
- Nausea and vomiting
- Feeling full soon after starting to eat
Many people with appendiceal cancer are diagnosed after the appendix is removed when it is believed they have appendicitis. For people without symptoms, these tumors can also be discovered if the person has an imaging test for another reason.
Imaging: If you have symptoms of appendiceal cancer, your doctor will use scans such as CT and MRI to look at the appendix.
Biopsy: To check if a tumor is appendiceal cancer your doctor will do a biopsy, taking a small sample from the tumor with a needle. An expert, called a pathologist, will study cells from the sample under the microscope to see what kind of tumor it is.
Biopsies of the appendix are very difficult to do. So, they are usually done on tissues in the body where the cancer may have spread).
Diagnostic Laparoscopy: This procedure uses an instrument inserted in the abdomen to view the organs in the area. If doctors see signs of tumors, they may biopsy the peritoneum (the membrane which lines the organs in the abdomen) to see if the cancer has spread.
Lab Tests: If a biopsy shows that you have appendiceal cancer, your doctor will order lab tests of your blood to check for protein levels. This may help decide the stage of your cancer, which means how advanced it is. Knowing the stage of your cancer is important for planning treatment.
Getting the correct diagnosis is very important to get the right treatment.
How is appendiceal cancer treated?
Treatment for each patient will be unique. You should go to an expert in appendiceal cancer treatment to decide the best approach for you.
Treatment options to discuss with your doctor include:
Surgery: You may have surgery to remove the appendix and any other organs and tissue in the abdomen and pelvic area that may be affected. Affected areas may include parts of your intestine, colon, and peritoneum.
Chemotherapy: When the appendiceal cancer has spread to other parts of the abdomen, chemotherapy is used to kill the cancer cells. In some cases, a specific way of giving chemotherapy called hyperthermic intraperitoneal chemotherapy, or HIPEC, is used. This treatment uses hot chemicals to wash the inside of the abdomen during surgery.
Does appendiceal cancer run in families?
Appendiceal cancer is not known to run in families.
How does appendiceal cancer form?
We do not yet know what causes appendiceal cancer. Scientists are always working to understand how cancer forms, but it can be hard to prove.
What is the prognosis for someone with appendiceal cancer?
The estimate of how a disease will affect you long-term is called prognosis. Each person is different and prognosis will depend on many factors, such as:
- The type of appendiceal cancer that you have
- Where the tumor is in your body
- If the cancer has spread to other parts of your body
- How much of the tumor was taken out during surgery
If you want information on your prognosis, it is important to talk to your doctor. Also, NCI has resources to help you understand cancer prognosis.
Doctors estimate appendiceal cancer survival rates by how groups of people with appendiceal cancer have done in the past. Because there are so few appendiceal cancer patients, these rates may not be very accurate
The 5-year survival rate for neuroendocrine tumors of the appendix and other low-grade tumors is between 67% to 97%. However, the 5-year survival rate for more advanced appendiceal cancer or that which has spread to other parts of the body can be much lower.