The appendix is a small pouch, about the size of your finger. It is found in the lower right part of your belly. 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 very rare. It is important to find a provider who has treated other patients with appendix cancer. It can be helpful to get a second opinion from another provider to figure out what treatment is best for you.

There are different types of appendiceal cancer:

Colonic-type adenocarcinoma: Often happens at the base of the appendix.
Neuroendocrine/Carcinoid tumor: Often happens in the tip of the appendix.
Appendiceal mucoceles: Mucoceles are little sacs of mucous in the appendix. These can be cancer (malignant) or benign (not cancer).
Signet-ring cell adenocarcinoma: This is a more aggressive and rare type of appendiceal cancer. The center of these cancer cells looks like a signet ring under a microscope.
Goblet cell carcinomas/Adenoneuroendocrines: Looks and acts like neuroendocrine and colonic-type adenocarcinomas (above) but are more aggressive than neuroendocrine tumors.
Paraganglioma: This is a rare tumor and is 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 do 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.
Your belly is bigger than normal. This could be from bloating or swelling.
Appendicitis (when your appendix is inflamed).
Having fluid in your belly (called ascites).
Change in your bowel movements.
Feeling full soon after eating.
Feeling a hard mass in your belly.
Nausea and vomiting.

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 reasons (like testing related to infertility for women). 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: After a biopsy, a pathology report will be made to summarize the results of the biopsy. This is sent to your healthcare provider. This report is an important part of planning your treatment. You can ask for a copy of your report to keep.
Blood work.
Laparoscopy.

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 (4). 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 guide 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 is medications that kill cancer cells. It may be used alone, before surgery to shrink the tumor to make surgery easier, or after surgery to keep the cancer from coming back (called recurrence). Sometimes chemotherapy is given directly into your belly (called intraperitoneal or IP chemo).
Targeted therapy: Targeted therapy is a type of treatment that attacks cancer cells. 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.