What Is Appendix Cancer?

While rare, appendiceal cancer is often manageable

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The appendix is a small organ in the digestive system that is connected to the large intestine on the right side of the abdomen. The purpose of the appendix is not well understood. Tumors, both those that are cancerous (malignant) and noncancerous (benign), can grow in the appendix.

Cancer of the appendix is rare, but it can spread to other organs and lead to complications. Between 2009 and 2018, cancer in the appendix occurred in less than two per 100,000 people in the United States.

Most of the time, the cancer is found incidentally during the process of looking for the source of another problem such as appendicitis (infection of the appendix). Because it is so rare, there is little in the way of clinical trial data that can be used to help make treatment decisions.

Patient with abdominal pain

Thitaree Mahawong / EyeEm / Getty Images

Types of Appendix Cancer

Appendix cancer may be classified in different ways. Putting these tumors into different groups has been difficult for researchers, and not all studies or cancer centers agree on how it should be done.

This article will outline one possible classification that includes four main groups. The group that any particular instance of this cancer falls into is based on the type of cells that are found in the tumor.

Colonic-Type Adenocarcinoma

The appendix has a lining called the epithelium. Appendiceal adenocarcinoma tumors start in this lining. It is thought to be the most common type of cancer in the appendix.

Colonic-type adenocarcinoma tumors are thought to be similar to the tumors found in colon cancer. The average age for diagnosis is in the early 60s, and it’s slightly more common in men.

Mucinous Adenocarcinoma

Mucinous tumors are so called because they excrete a substance called mucin. Mucin is a type of protein that is the main component of mucus. The average age of those diagnosed with this type of tumor is 60 years, and it occurs equally among genders.

It may be diagnosed after the tumor ruptures. A rupture causes the tumor cells and the mucin that has been secreted to enter into the abdomen (the peritoneal cavity).

Goblet Cell Adenocarcinoma

This is a rare subtype of appendix cancer. It is caused by tumors that have a mix of characteristics. The tumors found in this type of cancer have a cell type that is similar to those found in the intestine, called the goblet cell.

Goblet cells secrete mucin. The average age of diagnosis is 52 years, and it occurs equally across the sexes.

Neuroendocrine Tumor

These tumors are similar to those found in the small intestine. They may secrete serotonin, a chemical made in the digestive system that is most often associated with mood regulation, but is also responsible for other body functions such as vomiting and blood vessel constriction.

This type of cancer might be found after the appendix is removed (appendectomy) for presumed appendicitis. These tumors are more common in people between the ages of 38 to 48 years and found slightly more often in women.

Appendix Cancer Symptoms

For most cases of appendix cancer, especially in the early stages, there are no symptoms. Symptoms might only occur if the cancer has spread beyond the appendix to other organs or structures in the body or if a tumor has ruptured.

Many of the symptoms of appendix cancer are nonspecific and could be the result of several different types of diseases and conditions. Signs and symptoms of appendix cancer may include:

  • Abdominal distention (bloating)
  • Appendicitis
  • Bowel obstruction
  • Change in bowel habits (going to the bathroom more or less often)
  • Development of a hernia
  • Masses on the ovaries
  • Severe abdominal pain
  • Vague pain or discomfort in the lower right abdomen or the pelvis

When cancer spreads to another organ (such as the liver), it is an advanced form of appendix cancer. Spread of a neuroendocrine tumor into the liver can cause a condition called carcinoid syndrome. The signs and symptoms of carcinoid syndrome include:

  • Abdominal pain
  • Diarrhea
  • Feeling of fullness in the abdomen
  • Right-sided heart valve disease
  • Shortness of breath
  • Skin flushing (face and upper chest feel warm and become darker because of increased blood flow)
  • Wheezing

Causes

It’s not known what causes cancer in the appendix. No risk factors have been associated with the development of this type of cancer.

Diagnosis

Diagnosing appendix cancer can be challenging. This is because there may be no signs or symptoms in the early stages. When in the later stages, the symptoms are nonspecific and could be caused by a variety of diseases or conditions.

In the process of diagnosing appendix cancer, several different types of tests might be used to get a picture of what’s causing the symptoms.

  • Biopsy: A biopsy is a piece of tissue taken from an organ. In some cases, appendix cancer is only diagnosed after an appendectomy. A pathologist will study the appendix to look for tumors or other abnormalities.
  • Blood tests: Various blood tests can’t diagnose appendix cancer but can help a physician rule out other conditions. Tumor markers may be helpful in understanding that a tumor is present, but it does not indicate where that tumor is located or how advanced it might be.
  • Computed axial tomography (CAT) scan: In this test, a 3D image of the structures inside the body is created. Appendix cancer may be seen on a CT scan, and tumor size assessed. It can show whether cancer has spread outside of the appendix.
  • Magnetic resonance imaging (MRI): An MRI is a test that creates an image of the organs inside the body without using radiation. An MRI might help stage appendix cancer and see the size of any tumor(s).
  • Positron emission tomography (PET) scan: Sugar that has been treated with radioactive elements is given to the patient during a PET scan. Tumors will uptake the sugar and show up on the scan results. This test may be used to determine where any tumor(s) are located and if there are any found outside of the appendix.

Treatment

How appendix cancer will be managed is going to be different based on the specifics of each individual case.

Colonic-Type Adenocarcinoma

In many cases, surgery will be used to treat this type of appendix cancer. What will need to be determined, based on if the cancer has spread or not, is how extensive the surgery will be.

For cancer that has not spread, the appendix and part of the large intestine might be removed (called a right hemicolectomy). Lymph nodes are also usually removed, as these structures may be affected as much as 30% of the time.

If the cancer has spread to another organ, there may be a need for more extensive surgery. This could include removing parts of the liver or the lungs, for instance, if that is where the cancer has spread. After surgery, there may be a need for treatment with chemotherapy.

Mucinous Adenocarcinoma

This type of appendix cancer tends to stay localized to the appendix. If that is the case, removing the appendix is often the treatment. If the cancer is more advanced, there may be a need for a hemicolectomy. There may or may not be a need for chemotherapy for these patients.

This type of appendix cancer carries a risk of the appendix rupturing. If the appendix has ruptured, and mucin and tumors have moved into the abdominal cavity, more extensive surgery will be needed. This could include a type of surgery called a cytoreduction.

During a cytoreduction, several different abdominal structures may be removed either in part or completely. This includes the abdominal wall lining (the peritoneum), membrane connecting the stomach and abdominal organs (the omentum), small and large intestine, gallbladder, spleen, liver, uterus, and/or ovaries.

A type of chemotherapy that may be used is called intraperitoneal (IP) chemotherapy. This is a medication that is administered directly into the abdomen through a catheter. In some cases, this might be given during surgery in what’s called intraoperative hyperthermic intraperitoneal chemotherapy (HIPEC).

Goblet Cell Adenocarcinoma

Because there may be lymph nodes involved in this type of appendix cancer, surgery to have a right hemicolectomy might be used to treat it. If lymph nodes are found to be involved, there may also be a need for chemotherapy after surgery.

If the cancer has spread into the abdominal cavity, cytoreduction surgery followed by HIPEC or IP chemotherapy might also be needed.

Neuroendocrine Tumor

Because this tumor is sometimes considered benign, it may be undercounted because it would not be added to cancer registries. It is slightly more common in females, and in people who are White or Black. The average age of diagnosis is between 38 and 48 years.

These tumors begin in specialized cells in the lining of the appendix and are similar to those found in the small intestine. This cancer is generally found after an appendectomy, and it is rare for it to spread to other organs. When it does, however, the most common site is the liver.

When this cancer is diagnosed after an appendectomy, no other treatment is usually given. For larger tumors, a hemicolectomy may be done, and in the case of tumors spreading to other organs, other surgery may be needed.

Prognosis

The prognosis for appendix cancer varies widely depending on the type of cancer found and how it is treated. The way cancer prognosis is often discussed is with the five-year survival rate. That is the percentage of people with a type of cancer still living five years after their diagnosis.

For those with benign tumors of the appendix, the five-year survival rate might be anywhere between 91% and 100%.

However, more complicated cancers of the appendix, such as mucinous adenocarcinoma, might be lower, at 80%. This is because of a complication called pseudomyxoma peritonei (PMP), which may occur when a mucinous adenocarcinoma causes the appendix to rupture.

In PMP, the mucus from the ruptured tumors spreads throughout the abdominal cavity. This can cause complications throughout the digestive tract, including putting pressure on other organs, digestive problems, and even malnutrition.

Chemotherapy might also be given, but one study showed that a complete cytoreduction surgery was the most important factor in increasing survival rates with PMP.

There are no specific guidelines for monitoring people who have a diagnosis of appendix cancer. In some cases, especially when cancer has spread or the tumors are large, regular tests may be needed to keep tabs on progress. For others, chemotherapy and monitoring might be needed to be sure all cancer has been removed.

Coping

A diagnosis of appendix cancer can be difficult and bring up many different emotions, as well as questions.

This type of cancer is rare. Having a rare condition poses particular challenges because there are fewer data and studies available to use in decision making. In addition, the patient community is much smaller, making it harder to find someone else who has “been there.”

It can also come as a shock for those who had an appendectomy for what was thought to be appendicitis, only to find out there was a form of cancer in the appendix. Some people are diagnosed this way even when there were no other symptoms or reason to think that cancer was a potential diagnosis.

This can lead to difficulty in not only coping with the diagnosis, but also in the abrupt change to one’s life in order to deal with the necessary treatments (surgery and/or chemotherapy and regular monitoring).

Asking questions of healthcare professionals is going to be an important part of the diagnosis, treatment, and recovery process. With so much differentiation in the treatment and management of appendix cancer, it will be necessary to have a good understanding of every part of the process.

A Word From Verywell

The appendix is the little organ we don’t think much about. Many people may not even know that one can develop cancer in this organ and that it can lead to serious disease. However, the prognosis for most cases is good.

Surgery will be common, since removing the appendix is usually uncomplicated and people often recover well.

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