Appendix cancer, also called appendiceal cancer, is when abnormal cells grow and form a tumor in the appendix. Your appendix is a little pouch-like organ attached to the lower right side of your large intestine.
Tumors in the appendix can be noncancerous, too — they're called benign.
There are two main kinds of appendix cancer: adenocarcinomas and neuroendocrine tumors (NETs). Although appendix cancer is rare, a recent study reports that it has more than quadrupled in people born between 1981 and 1989.
Learn about the different types of cancers, how your doctor stages your tumor, and explore the best treatments for your appendiceal cancer.
Types of Appendix Cancers
The two types of appendix cancers grow from different cells in your appendix:
Adenocarcinoma tumors grow from the lining of your appendix.
NETs grow from special cells called enterochromaffin cells (ECs) that make hormones in your intestines.
Appendix adenocarcinoma
Appendix cancer that grows from the lining of your stomach is grouped into four main subtypes:
Mucinous adenocarcinoma. It's a type of tumor that can make mucus and can build up to cause bloating. Also called mucinous neoplasms, your tumor can be low-grade (not as harmful) or high-grade (spreads faster).
Colonic-type (nonmucinous). It's called “colonic-type” because the cancer cells look like colon cancer and you’re often diagnosed at a similar age. The tumor grows near the bottom lining of your appendix and usually spreads outside of your appendix — often mistaken for appendicitis.
Signet ring cell adenocarcinoma. This rare form of cancer is usually poorly differentiated --- the cancer cells don't look like healthy ones. The mucus inside the cancer cell pushes up on structures and looks like a signet ring.
Goblet cell adenocarcinoma. This very rare type of cancer looks like adenocarcinomas and NETs. Only about 0.01 to 0.05 in 100,000 people get this type of cancer each year in the U.S.
Neuroendocrine tumors
About half of all appendix cancers are slow growing NETs, but they can spread to other organs. These tumors can send out serotonin, insulin, and glucagon hormones. But somatostatin is a hormone made in your gastrointestinal (GI) tract and other parts of your body. It can stop your tumor from making hormones to lower levels.
What Causes Appendix Cancer?
It’s still unclear what causes appendix cancer. But DNA changes can cause some appendix cells to grow quickly and form a tumor.
Who's at risk for appendix cancer?
Although appendix cancer can affect anyone, some factors can raise your risk. You may have a higher risk for appendix cancer if you:
- Are age 50 or older
- Are White
- Use tobacco or smoke
- Have inflammatory stomach problems (like inflammatory bowel disease)
- Have appendicitis or a family history of appendix cancer
- Have multiple endocrine neoplasia type 1 (MEN1)
- Have anemia
- Have tumors in your pancreas (gastrinomas) or intestines (Zollinger-Ellison syndrome)
Slightly more women are diagnosed with NETs than men.
What Are the Symptoms of Appendix Cancer?
Many people with early-stage appendiceal cancer don't show symptoms. And about 20 in 100 people with appendix cancer aren’t diagnosed until their appendectomy — the surgery to remove your appendix.
With appendix cancer symptoms, you may get:
- Serious belly pain, especially on your right side
- Fluid in your belly or bloating
- A lump in your belly
- Vomiting and nausea
- Changers in your bowel movements
- A feeling like you're full while eating
Peritoneal disease
If your appendix cancer grows, it can spread to other organs. “The disease gets outside into the peritoneal cavity, which then we call peritoneal disease,” says Benjamin Powers, MD, a surgical oncologist and assistant professor at the University of Maryland School of Medicine in Baltimore. “[You] can present with symptoms of bloating, abdominal fullness, and some cramping after meals."
Your peritoneal cavity is the space inside your belly that holds all your organs, like your stomach and intestines. You can also get a hernia from the pressure that the mucus puts on your belly and muscles, says Powers.
Carcinoid syndrome symptoms
If your tumors are NETs, you may get carcinoid syndrome. It's a group of symptoms that can happen because of the extra hormones the tumor releases.
With carcinoid syndrome, you can have:
- Flushing that comes and goes
- Wheezing
- Diarrhea
- Heart valve problems
Is pseudomyxoma peritonei (PMP) a sign of appendix cancer?
Pseudomyxoma peritonei (PMP) literally stands for “false mucinous tumor of the peritoneum.” PMP is a rare type of cancer that makes a jelly-like tumor — as big as 20 to 30 pounds. And PMP can be a sign of appendix cancer in about 2 out of every 10,000 laparotomies — surgery to diagnose your symptoms.
When to call the doctor
Some symptoms can mean problems with your stomach or intestines that need urgent medical care.
Get medical care right away and go to the nearest emergency center if you notice:
- Serious belly pain, bloating, or swelling
- Pain that gets worse when you cough
- Fever or chills
- Vomiting or nausea that doesn't stop
- Diarrhea or constipation that doesn't go away
- Blood, black, or tarry stools (poop) mixed with mucus
- Can't pass urine (pee)
- Blood in your urine
Appendix Cancer Diagnosis
Because appendix cancer often doesn’t have symptoms, you're usually diagnosed during your appendectomy. After your appendix is removed, your doctor can see the cancer cells under a microscope. “Some studies show that as few as 1% to 2% of [appendectomy surgeries] have appendiceal tumors,” says Powers. “But other studies suggest it may be as high as 30%.”
But if you have symptoms, your doctor may order blood tests, imaging scans, or perform a procedure.
Blood tests
Your doctor may test your blood for:
- Cancer antigen 19-9 (CA 19-9)
- Cancer antigen 125 (CA-125)
- Carcinoembryonic antigen (CEA)
- White and red blood cells
- C-reactive protein (CRP)
- Chromogranin A (CgA)
Your doctor may also test your urine for serotonin or its byproducts to check for carcinoid syndrome.
Imaging scans
Here are some common imaging tests your doctor may order:
- A CT scan uses X-rays to make a detailed picture of your appendix.
- Endoscopic ultrasound uses a thin tube with a camera on the end and ultrasound to make pictures of your appendix.
- An MIBG nuclear medicine scan uses a small amount of radioactive iodine, which your cancer cells break down faster or slower. Cancer cells show up as “hot spots” (brighter) or “cold spots” (duller) in the picture.
- MRI uses strong magnets and radio waves to make pictures of your organs.
- A positron emission tomography (PET) scan tells your doctor if your cancer has spread to other organs.
Biopsy
Your doctor takes a small piece of tissue from your appendix to look at the cells under a microscope. This test can tell you the type and stage of your appendix cancer.
Laparoscopy
During surgery, your doctor makes a few small cuts in your belly to insert a small scope with a camera on the end. They’ll check your appendix, nearby organs, and tissues for cancer.
Stages of Appendix Cancer
Your doctor will stage your appendix cancer to help you decide on the best treatment. Your cancer stage can depend on how big your tumor is and its location. Most doctors use the American Joint Committee on Cancer (AJCC) staging system (stages I to IV), but most people use numbers 1 to 4.
Although NETs are staged differently, appendix adenocarcinomas are staged the same and include:
- Mucinous
- Colonic-type
- Goblet cell
- Signet ring
Stage 0
Often called carcinoma in situ, your adenocarcinoma cells are in the innermost lining of your appendix and haven't spread beyond one area.
Stage 1
Your adenocarcinoma has spread into the deepest layer of your appendix wall, but not to other parts of your body.
NETs cancer cells commonly grow at the end of your appendix. Your stage 1 tumor is usually 2 centimeters (cm) or less, about the size of a peanut, but hasn’t spread to nearby lymph nodes.
Stage 2
Stage 2 appendix cancer hasn't spread into nearby lymph nodes or organs.
For adenocarcinoma, your tumor has spread into the smooth muscle layer. The stage 2 subtypes include:
- 2A: The cancer cells are in nearby connective and fatty tissues.
- 2B: Your cancer has spread to your appendix lining.
- 2C: The cancer cells are in your appendix muscle layers.
For NETs, your tumor is between 2 to 4 cm big --- that's up to the size of a walnut. Stage 2 subtypes include:
2A: Your tumor is 2 cm or smaller or has spread to the connective and fatty tissues in your appendix.
2B: Your tumor is more than 2 cm big or has spread to nearby tissues of your appendix.
Stage 3
Stage 3 cancer can grow beyond your appendix into nearby lymph nodes but not to distant organs.
Adenocarcinoma stage 3 substages include:
- 3A: Your tumor has spread into your peritoneal (belly) cavity.
- 3B: Your cancer is in nearby lymph nodes.
- 3C: The cancer is in nearby lymph nodes and organs.
Bigger than a walnut (>4 cm), your NETs tumor has spread into layers of your appendix. Stage 3 subgroups include:
- 3A: About 4 cm or bigger, the tumor hasn't spread beyond the appendix.
- 3B: A tumor of any size has spread to nearby lymph nodes.
- 3C: Your cancer has spread to nearby lymph nodes and organs.
Stage 4
Your appendix cancer has spread to distant organs.
Stage 4 adenocarcinoma includes subgroups:
- 4A: Your cancer has spread to other organs but not distant lymph nodes.
- 4B: The cancer is in one to three distant lymph nodes.
- 4C: The cancer has spread to four or more distant lymph nodes.
Your NETs cancer has spread to nearby lymph nodes and distant organs.
Where does appendix cancer spread to?
When appendix cancer begins to spread, it usually enters your peritoneal cavity and can spread to your abdominal (belly) lymph nodes. It rarely spreads beyond that but when it does, it can affect your:
- Ovaries
- Intestines
- Uterus
- Liver
- Spleen
- Lung
- Bone
How Is Appendix Cancer Treated?
Various medicines, procedures, and surgery can treat appendix cancer. It can depend on many different factors and your cancer treatment plan.
Factors that affect appendix cancer treatment
Your cancer treatment can change depending on factors like your:
- Cancer type
- Cancer stage
- Surgery and history
- Overall health
- Medical conditions
- Treatment choice
- Cancer-related syndromes (carcinoid syndrome or carcinoid heart syndrome)
Your doctor may suggest waiting if your cancer is very early stage. Your doctor will monitor you and you'll go in for follow-up visits, imaging scans, and blood tests.
Surgery for appendix cancer
There are three main types of surgery to treat appendix cancer:
- Appendectomy: The surgery removes your appendix. If your tumor is early stage, well-differentiated, and hasn't spread, this may be the only treatment that you'll need.
Hemicolectomy: Usually, your surgeon removes the entire right side of your colon and your appendix. Your doctor will do a lymphadenectomy to take out any lymph nodes with cancer, too.
Cytoreductive (debulking) surgery: Your surgeon takes out any organs (or as much of the tumor as possible, debulk) with cancer cells along with any fluid in your belly (ascites).
Hyperthermic intraperitoneal chemotherapy (HIPEC)
If your appendix ruptures, your surgeon may suggest cytoreductive surgery and add heated chemotherapy into your belly for one to two hours.
"[Your chemo] is swished around inside, spreading it throughout your [belly], and then drained out," says Powers. The heat also helps the chemo medicine work better.
“[HIPEC] is a major surgery,” Powers says. “We will go in, remove all [your tumors] and affected organs — then we're going to do a hot chemotherapy bath.”
You'll likely stay in the hospital for 8 to 10 days to recover, but it may take even longer to "recover from the intensive surgery," says Powers. “We also know that patients who get this treatment have an overall (median) survival that goes well beyond a decade.”
Because the medicine goes into your belly, you may get fewer side effects. Chemotherapy can also go into your IV (in your vein), also called systemic therapy. You may get this chemo before or after your surgery to help shrink or kill any cancer cells.
“Given the rarity of [appendix cancer], a lot of the treatments for systemic therapy have been borrowed from colorectal cancer,” Powers said.
Treatments for NETs
Because NETs can make and release hormones, you may get certain complications.
Your doctor may suggest treatments such as:
Surgery. Appendectomy, right hemicolectomy, and cytoreductive surgery can treat NETs.
Chemotherapy. Chemo before or after your surgery can help shrink or destroy your cancer cells.
Radiofrequency ablation. The procedure uses a probe that emits radio waves to destroy the blood vessels that supply oxygen to your tumor cells.
Cryosurgery. Also called cryotherapy, an ultrasound helps guide a device to freeze the cancer cells and destroy your tumor.
Hepatic artery embolization. Can block the blood vessels that supply oxygen to the tumors inside your liver to shrink and destroy them.
Liver transplant. Replaces your liver (if your cancer spreads to your liver) with a donated one.
Chemoembolization. Mixes chemo medicine with a special substance to block and cut off blood flow directly inside the artery (blood vessel) that feeds oxygen to your tumor in your liver.
Everolimus (Afinitor). A targeted therapy that may help if chemotherapy isn’t working for you.
Carcinoid syndrome treatment
Peptide receptor radionuclide therapy (PRRT) can inject a lab-made hormone that mimics somatostatin to block NETs from making hormones. And some of the medicines contain radiation to shrink your cancer cells, too.
PRRT can help
- Slow the growth of cancer cells
- Lower hormone levels from NETs
- Prevent carcinoid syndrome
Can Appendix Cancer Be Cured?
Some appendix cancers can be cured, especially low-grade NETS that are diagnosed early.
How rare is appendix cancer?
Although it’s rare, a recent study shows that appendix cancer has quadrupled in people born between 1981 and 1989. More people are getting it each year and experts aren’t sure why. In fact, fewer than 1,000 people in the U.S. have appendix cancer. "This rarity makes it hard to pinpoint a lot about the disease," says Powers.
What is the survival rate of appendix cancer?
Between 67 to 97 in 100 people with NETs and other slowly spreading appendix cancers live for five years. But these numbers can depend on many factors such as your health, age, cancer stage, and treatment.
Takeaways
Although appendiceal cancer is a rare growth from your appendix cells, more people are getting it each year. Your appendix is a small pouch-like organ attached to the right side of your intestines. Appendix cancer usually doesn’t cause symptoms, but if you get serious belly pain, signs of infection, vomiting, diarrhea, or bowel changes, get emergency medical care right away.
Appendix Cancer FAQs
Can you get appendix cancer after having your appendix removed?
It’s very rare, but you can get appendix cancer after it’s taken out. A stump (like an appendix) can form from a few cancer cells left over from surgery.
Does appendix cancer spread to the colon?
Yes, because your appendix is close to your colon. That's why a hemicolectomy commonly treats appendix cancer and removes your colon, too.
How painful is appendix cancer?
Most people with appendix cancer don’t get symptoms. Your symptoms can depend on your appendix cancer type, location, and stage.
If your appendix cancer has spread, you can get symptoms for appendicitis:
Serious belly pain (can get worse when you cough)
Fever
Changes in your bowel movements
Nausea and vomiting
