Appendix Cancer: The Basics

Appendix Cancer: The Basics 

The appendix is a small pouch, about the size of your finger. It is found where your large and small intestines meet. Appendix cancer (also called appendiceal cancer) is caused by cells in the appendix growing out of control. As the number of cells grow, they form a tumor. Appendix cancer is quite rare. It affects about 1 or 2 people per 1 million people every year in the United States (fewer than 1,500 people per year). It may be helpful to get a second opinion from another cancer center to compare and decide what treatment is best for you.

There are a few different types of appendiceal cancer:

• Colonic-type adenocarcinoma: Often happens at the base of the appendix. This is the most common type.
• Neuroendocrine/Carcinoid tumor: Often happens in the tip of the appendix.
• Appendiceal mucoceles: Mucoceles are little sacs of mucous. These can be cancer (malignant) or benign (not cancer). 
• Signet-ring cell adenocarcinoma: The center of these cancer cells looks like a signet ring under a microscope.
• Goblet cell carcinomas/Adenoneuroendocrines: Look and act like neuroendocrine and colonic-type adenocarcinomas (above). 
• Paraganglioma: Often benign (not cancer). 

Appendix cancer that has spread from the appendix to another part of the body is called metastatic cancer.

Risk Factors

It is not known what causes appendix cancer. There is nothing you can change that will lower your risk. The only known risk factors are:

• Sex: Neuroendocrine tumors in the appendix are more common in women. Adenocarcinomas are more common in men.
• Age: As you age, your risk of appendix cancer gets higher.

Screening

There are no standard screening tests.

Signs and Symptoms of Appendix Cancer

• Pain in the belly or near the hips.
• Feeling swollen in the belly.
• Appendicitis (when your appendix is inflamed). 
• Having fluid in your belly (called ascites).
• Your waistline gets bigger quickly.
• Change in your bowel movements.
• Feeling full soon after eating.
• Feeling a hard mass in your belly.
• It can be found incidentally (by chance) when a woman is having a hard time having a baby (called infertility). 

Diagnosis of Appendix Cancer

Appendix cancer is often found by chance or by accident (called incidentally) when a person has their appendix removed for appendicitis or other reason. If you are having any of the signs or symptoms above, your provider will do a physical exam. If your provider thinks you may have appendix cancer, you may also have:

• Ultrasound.
• CT scan.
• MRI.
• Octreotide Scan: Only used for neuroendocrine tumors.
• Biopsy: A pathology report summarizes the results of the biopsy and is sent to your healthcare provider. This report is an important part of planning your treatment. You can request a copy of your report for your records.

Staging Appendix Cancer

To guide treatment, appendix cancer is "staged." The stage is based on:

• Size and location of the tumor.
• Whether cancer cells are found in the lymph nodes.
• Whether cancer cells are found in other areas of the body.

Stages range from stage 0 (zero) to stage IV (four). Stage 0 is the smallest and least amount of cancer. Stage four means the cancer has spread to other areas of the body. The stage and type of appendix cancer will help choose your treatment plan.

Treatment

Treatment for appendix cancer depends on the type of appendix cancer you have and the stage. It also depends on your health at the time of diagnosis. Because appendix cancer is so rare, there are no formal guidelines for treatment. Adenocarcinoma is often treated like colon cancer because the cells are similar. 

Treatment options may be:

• Surgery: Your appendix may be taken out (called appendectomy), part of your colon may be taken out (called hemicolectomy), or the inner lining of your belly may be taken out (called peritonectomy). You may also have as much of the tumor removed as possible, called debulking surgery. Your surgeon will also remove lymph nodes in the area to see if any cancer has spread to them.
• Chemotherapy given by IV (intravenous) may be used alone, or before surgery to shrink the tumor to make surgery easier, or after surgery to keep the cancer from coming back (called recurrence). In some cases, chemotherapy is given directly into your belly (called intraperitoneal or IP chemo).
• Targeted therapy: Your provider may run tests on your tumor cells to see if targeted therapy will work for you.
• Radiation therapy is not often used to treat appendiceal cancer but may be used to help with your symptoms.  

Talk with your provider about which course of treatment is right for you. 

Resources for More Information

This article is a basic guide to appendix cancer. You can learn more about appendix cancer and treatment by visiting these sites:

https://www.cancer.net/cancer-types/appendix-cancer/introduction 

https://www.cancer.gov/pediatric-adult-rare-tumor/rare-tumors/rare-digestive-system-tumors/appendiceal-cancer