Appendix Cancer

What is appendix cancer?

Appendix cancer — also called appendiceal cancer — is a rare disease. It occurs when the cells in your appendix mutate (change) and grow out of control.

Your appendix is part of your digestive system. It’s a small tube-like pouch located on the lower right side of your abdomen, near the junction of your large intestine (colon) and small intestine. Scientists don’t know for sure what your appendix does. But some believe it helps your immune system function. Others consider it a vestigial organ (one that’s no longer useful in modern times).

Types of appendix cancer

There are several benign (noncancerous) and malignant tumors that can develop in your appendix. Malignant, or cancerous ones, have the potential to grow and spread. Experts classify malignant appendix tumors based on the type of cell where the cancer starts. Types include:

• Appendiceal adenocarcinoma.
• Neuroendocrine tumors.

Appendiceal adenocarcinoma (epithelial tumors)

Most appendix cancers are appendiceal adenocarcinoma. Adenocarcinoma cancers start in the glandular tissue that lines your organs. There are several categories of appendiceal adenocarcinoma, including:

• Mucinous adenocarcinoma. This type starts in the lining of your appendix and releases mucin, a component of mucus. Although these tumors can spread, most don’t spread beyond your abdomen.
• Colonic-type (nonmucinous) adenocarcinoma. These tumors develop near the bottom of your appendix. They behave a lot like colon cancer tumors and cause many of the same symptoms.
• Signet ring cell adenocarcinoma. This variant is rare, but it can occasionally form in your appendix. The cancer cells secrete and store large amounts of mucin. It’s called signet ring adenocarcinoma because the cancer cells have a signet ring appearance under a microscope.
• Goblet cell adenocarcinoma. This extremely rare variant of adenocarcinoma has some features of neuroendocrine tumors, too.

Appendiceal neuroendocrine tumors (carcinoid tumors)

Neuroendocrine tumors affect neuroendocrine cells, which receive signals from your nervous system and release hormones. In most cases, these tumors grow slowly.

How common is appendix cancer?

Appendix cancer is extremely rare. In the United States, appendix cancer affects approximately 1 to 2 people out of every 1 million each year. That’s significantly less than even 1% of the population.

What are the symptoms of appendix cancer?

You can have appendix cancer without developing symptoms. Or you may not notice symptoms until the tumor has spread. Appendix cancer symptoms vary from person to person and may include:

• Appendicitis (inflammation or infection of your appendix).
• Bloating (fullness or tightness in your belly).
• Fluid buildup in your abdomen (ascites).
• Increase in waist size.
• Pain in your abdomen or pelvis.
• Changes in bowel habits (including diarrhea).
• Nausea and vomiting.
• Feeling full soon after you start eating (early satiety).

Sometimes, appendix cancer occurs alongside a rare condition called pseudomyxoma peritonei (PMP). With PMP, cancer cells secrete jelly-like mucin that can cause your appendix to swell. Over time, it can cause symptoms like a bloated stomach and abdominal pain.

What causes appendix cancer?

Appendix cancer starts when the cells in your appendix mutate and grow out of control. But experts don’t know what sets this process in motion.

Risk factors

Certain factors may increase your risk of appendix cancer, including:

• Age. Appendix cancer can occur at any age, but it’s more likely to develop in people between 40 and 60. Most people diagnosed are in their 50s.
• Sex. People assigned female at birth (AFAB) are more likely than people assigned male at birth (AMAB) to develop neuroendocrine tumors in their appendix.
• Smoking or using tobacco products. Tobacco use can increase your chances of all cancers, including appendix cancer.
• Medical history. Certain health conditions, including atrophic gastritis, pernicious anemia and Zollinger-Ellison syndrome, may increase your risk for appendix cancer.
• Family history of cancer. A recent study suggests that some people with appendix cancer inherit genes that increase their cancer risk. But more research is needed to know if some forms might be hereditary (run in families).

How is appendix cancer diagnosed?

People with appendix cancer often see their healthcare providers because they’re having symptoms of appendicitis. Diagnosis usually happens after an appendectomy (removal of the appendix). Sometimes, existing tumors show up on imaging tests or surgery for an unrelated condition.

If your provider suspects appendix cancer, they’ll recommend more tests, which may include:

• Imaging tests. Your provider may recommend a computed tomography (CT) scan or MRI (magnetic resonance imaging). These tests take pictures of the tissues inside your body. They can show tumors and reveal signs of cancer spread. When it spreads, appendix cancer advances to nearby abdominal organs or the tissue lining them (peritoneum).
• Laparoscopy. Your provider inserts a laparoscope — a long, slender fiber optic instrument — through an incision (cut) in your abdomen. A small camera captures images of your appendix and projects them onto a screen.
• Biopsy. During this procedure, your provider takes a tissue sample and sends it to a pathology lab to test for cancer cells. It can be difficult to take a biopsy of the appendix. So, if the cancer has potentially spread to another region, your provider will take a sample from that area.
• Blood tests. If your biopsy results are positive for appendix cancer, then your provider will recommend lab tests to check your protein levels. Specific protein levels can help determine how advanced the cancer is.

Stages of appendix cancer

Cancer staging allows healthcare providers to determine how advanced cancer is, develop the best treatment plan and determine likely treatment outcomes.

Providers use different staging guidelines based on the type of tumor:

• Appendiceal adenocarcinomas: Providers use the TNM staging system. They consider how large tumors are (T), if the cancer has spread to your lymph nodes (N) and if it’s spread to distant organs (M). Cancer that has spread is called metastatic cancer. Providers consider these factors together to assign a stage from one to four, with one being early-stage cancer and four being advanced.
• Appendiceal neuroendocrine tumors: Providers stage neuroendocrine tumors based on whether surgery can remove them completely. They also consider the tumor grade (how abnormal the cells look beneath a microscope). Your prognosis is better if you have a low-grade tumor (few abnormal cells) that a provider can remove with surgery.

Staging is especially complex in appendix cancer because there are so many different types of tumors. Each type has different characteristics that will shape your treatment options and prognosis.

But don’t be intimidated. Ask your healthcare provider to explain what your cancer type and stage mean for you.

How is appendix cancer treated?

There are several potential appendix cancer treatments, including surgery and drug treatments. Your healthcare provider will consider several things before planning your treatment, including the size and stage of the tumor, your overall health and your personal preferences.

Surgery

Surgery is the most common treatment for appendix cancer. Surgical approaches include:

• Appendectomy. Removing your appendix may be enough to treat small tumors less than 1 or 2 centimeters (less than an inch).
• Hemicolectomy. You may need additional surgery, like hemicolectomy, for larger and more aggressive tumors. It involves removing part of your large intestine and some lymph nodes in addition to removing your appendix.
• Cytoreductive (debulking) surgery. You may need more extensive surgery for cancer that has spread throughout your abdomen. Your surgeon will remove as much of the tumor as possible, including parts of affected organs.

Drug treatments

You may need drug treatments for appendix cancer if surgery can’t get rid of all the cancer. Treatments include:

• Chemotherapy. This treatment uses drugs to kill cancer cells that have spread beyond your appendix. It also destroys any cancer cells that may remain after surgery. You can receive the medicine through an injection or by taking a pill.
• Hyperthermic intraperitoneal chemotherapy (HIPEC). HIPEC is a special type of chemotherapy treatment that usually happens during surgery. It involves heating chemotherapy drugs and circulating them inside your abdominal cavity. The heat and direct application make the chemo more powerful and effective.
• Targeted drug therapy. The goal of this treatment is to target cancer cells while limiting damage to healthy cells. Specific drugs target certain genes or proteins that encourage cancer growth. Drugs providers use in targeted therapy for appendix cancer include cetuximab, bevacizumab, ramucirumab and panitumumab.

What can I expect if I have appendix cancer?

Your experience depends on many things, like the type of tumor, its size and its grade. Your overall health and how you respond to treatment are important, too.

Some types of appendix cancer are curable. For example, most low-grade appendiceal neuroendocrine tumors are curable with surgery. Generally, the smaller the tumor, the more likely it is that treatment will get rid of the cancer for good. Larger tumors typically spread quickly and may not respond as well to treatment.

Your healthcare provider can offer guidance on what to expect based on your diagnosis.

What is the survival rate of appendix cancer?

The five-year survival rate for low-grade appendix cancer is 67% to 97%. That means that 67% to 97% of people diagnosed with the disease are still alive five years later. The five-year survival rate for aggressive tumors or late-stage appendix cancer can be much lower.

Remember that survival rates can’t tell you how you’ll respond to treatment or how long you’ll live. These numbers represent the experiences of people who’ve been diagnosed with appendix cancer in the past. Because appendix cancer is so rare, information about life expectancy may not be precise. If you have questions about survival rates, talk to your healthcare provider.

When should I see my healthcare provider?

Call your provider immediately if you develop appendix cancer symptoms, including appendicitis, bloating or abdominal pain.

If you already have an appendix cancer diagnosis, call your provider if your symptoms change or worsen. Let them know if you’re experiencing treatment side effects. They can recommend ways to ease your discomfort. They may also connect you with palliative care resources. Palliative care professionals help people with various illnesses (including non-life-threatening ones) manage symptoms.

What questions should I ask my healthcare provider?

Learning all you can about your condition can help you make informed decisions about your health. Questions to ask your provider include:

• What kind of appendix tumor do I have?
• What size is the tumor?
• What stage and grade of appendix cancer do I have?
• What are my treatment options?
• When do I need to start treatment?
• Will I be able to work while getting cancer treatment?
• Are there resources or support groups available to me?