Your appendix is a narrow tube-shaped sac that connects to your colon near the beginning of your large intestines. The purpose of your appendix still isn’t clear, but some scientists think that it may be a part of your immune system.
Appendix cancer is sometimes called appendiceal cancer. It occurs when healthy cells become abnormal and grow rapidly. These cancerous cells become a mass or tumor inside the appendix, which is often found by accident after surgical removal of the appendix.
Appendix cancer is considered rare. In the United States, it affects about one or two people per million people each year, according to the
In this article, we review the different types and classifications of appendix cancer, along with symptoms, risk factors, and treatment options.
There are several classifications of appendix cancers, but they’re not well defined. That’s due to the rarity of this type of cancer, which limits the amount of research.
Classifications of appendix cancer are as follows:
In this type, sometimes known as typical carcinoid, a tumor forms with certain cells from the wall of the bowel.
It accounts for about
Mucinous adenocarcinoma of the appendix
Mucinous adenocarcinoma of the appendix, also called MAA, occurs in females and males equally. The average age of onset is around
Most of the time, MAA is discovered after a rupture of the tumor that leads to the release of mucin.
This type of cancer accounts for 10 percent of appendix cancers and acts similar to colorectal cancer. It usually appears in people between the ages of
Colonic-type adenocarcinoma usually starts in the base of your appendix.
Goblet cell adenocarcinoma
Goblet cell carcinoid is also called GCC. It develops in both neuroendocrine cells and a type of epithelial cell called goblet cells that produce a jelly-like substance called mucin.
GCC most often onsets between the ages of 50 to 55. Typically, it causes either appendicitis or abdominal pain with a mass.
Signet ring cell adenocarcinoma
Signet ring cell adenocarcinoma is considered a subtype of colonic-type adenocarcinoma or mucinous adenocarcinoma.
While it’s the most aggressive type and most likely to spread to other organs, it’s very rare. This type more commonly occurs in the colon or stomach but can develop in the appendix as well.
Your doctor may also discover it during a routine colonoscopy. However, if there are symptoms, they may include:
- bloated abdomen
- ovarian masses
- chronic or severe abdominal pain
- nonspecific discomfort in the lower right abdomen
- changes in bowel function (such as constipation, obstruction, diarrhea)
Many of these symptoms may not occur until the cancer is more advanced. In about a
Doctors often use the TNM staging system to describe the extent of appendix cancer. TNM stands for
- Tumor. The extent of the cancer in your appendix.
- Node. Whether the cancer has reached your lymph nodes.
- Metastasis. Whether the cancer has spread beyond your pancreas.
Each of three aspects of the tumor is staged and plays a role in determining the overall stage of the cancer.
The size and location of the appendiceal tumor are given a score from T0 to score T4b:
|T0||No evidence of cancer|
|Tis||Evidence of cancer in situ, or cancer cells in the first layer of your appendix|
|T1||Evidence of cancer cells in the next layer of your appendix called the submucosa|
|T2||The cancer has entered a deep layer of your appendix called the muscularis propria|
|T3||The cancer has spread into a layer of connective tissue called the subserosa or the blood supply of your appendix called the mesoappendix|
|T4||The cancer has grown into the lining of your abdominal cavity or nearby organs|
|T4a||Evidence of the tumor in the visceral peritoneum, the tissue that covers the outer surface of most organs|
|T4b||Cancer is present in other organs or structures such as your colon|
The extent that your cancer has invaded your lymph nodes is given a score from N0 to N2:
|N0||No cancer in surrounding lymph nodes|
|N1||Cancer is in 1 to 3 lymph nodes in the area|
|N2||Cancer is in 4 or more lymph nodes in the area|
The extent that the cancer has spread to other parts of your body is given a score from M0 to M1c:
|M0||Cancer has not spread to other parts of your body|
|M1||Cancer has spread to other parts of your body|
|M1a||It has spread to a particular region called the intraperitoneal acellular mucin|
|M1b||It has spread within the peritoneum further than stage M1a|
|M1c||It has spread beyond the peritoneum|
Doctors assign a grade to your cancer based on how different cancer cells look from healthy cells under a microscope. A higher-grade cancer is expected to spread quicker.
Appendiceal cancer is given a grade from G1 to g4:
|G1||Tumor cells look similar to healthy cells|
|G2||Tumor cells look fairly different from healthy cells|
|G3||Tumor cells look very different from healthy cells|
|G4||The tumor cells look distinct compared to healthy cells|
TNM staging system
Doctors assign an overall stage to your cancer based on TNM and grade scores. A higher stage means the cancer has progressed further and has a worse prognosis.
The table below shows staging for appendiceal carcinomas. It’s worth noting that the staging descriptions for other types of appendix cancers — such as neuroendocrine tumors of the appendix — are slightly different.
|Stage 0||Tis + N0 + M0|
|Stage 1||T1 or T2 + N0 + M0|
|Stage 2A||T3 + N0 + M0|
|Stage 2B||T4a + N0 + M0|
|Stage 2C||T4b + N0 + M0|
|Stage 3A||T1 or T2 + N1 + M0|
|Stage 3B||T3 or T4 + N1 + M0|
|Stage 3C||Any T + N2 + M0|
|Stage 4A||Any T + N0 + M1a or any T + any N + M1b + G1|
|Stage 4B||Any T + any N + M1b + G2 or G3|
|Stage 4C||Any T + any N + M1c + any G|
The cause of appendix cancer is largely unknown and no avoidable risk factors have been identified. However, appendix cancer becomes more common with age and is rare in children.
Neuroendocrine tumors are more common in women than men.
Although more research is needed, a few potential risk factors have been suggested by experts, including:
- pernicious anemia, a deficiency of vitamin B12
- atrophic gastritis, or long-term inflammation of the stomach lining
- Zollinger-Ellison syndrome, a condition of the digestive tract
- a family history of multiple endocrine neoplasia type 1 (MEN1), a disorder that leads to tumors in the glands that produce hormones
The treatment for appendix cancer depends on the:
- type of tumor
- stage of the cancer
- person’s overall health
A multidisciplinary team of medical professionals will help you through your treatment. Your team will include a variety of professionals that may include doctors, nurse practitioners, dietitians, counselors, and more. A type of doctor called a surgical oncologist will operate on your cancer while a medical oncologist will develop your chemotherapy plan.
Surgery is the most common treatment for localized appendix cancer. If the cancer is localized to the appendix only, the treatment is usually to remove the appendix. This is also called an appendectomy.
For some types of appendix cancer, or if the tumor is larger, your doctor may recommend removing one-half of your colon and also some lymph nodes. Surgery to remove half of your colon is called a hemicolectomy.
If the cancer has spread, your doctor may recommend cytoreductive surgery, also called debulking. In this type of surgery, the surgeon will remove the tumor, surrounding fluid, and possibly any nearby organs that are attached to the tumor.
Treatment may include chemotherapy before or after surgery if:
- the tumor is larger than 2 centimeters
- the cancer has spread, especially to the lymph nodes
- the cancer is more aggressive
Types of chemotherapy include:
- systemic chemotherapy given intravenously or by mouth
- regional chemotherapy given directly into the abdomen, such as intraperitoneal chemotherapy (EPIC) or hyperthermic intraperitoneal chemotherapy (HIPEC)
- a combination of systemic and regional chemotherapies
Radiation therapy is rarely used to treat appendix cancer. However, it may be recommended if your cancer spreads to other body parts.
After surgery, your doctor will follow up with imaging tests, such as a CT scan or MRI, to ensure the tumor is gone.
Since appendix cancer is such a rare condition, there’s little information available about its recurrence or survival rates.
According to the American Society of Clinical Oncology, , the 5-year survival rate for Grade 1 and Grade 2 neuroendocrine tumors is between 67 to 97 percent. The survival rate for advanced appendix cancer that has spread to other body parts is lower.
Survival rates also vary between cancer types. Neuroendocrine tumors have the highest chance of survival while signet-ring cell tumors have the lowest five-year survival rate at
The 5-year survival rate increases for some cases of appendix cancer when part of the colon is also removed and chemotherapy is used. However, not all cases of appendix cancer require these additional treatments.
The survival rate and outlook are generally good for most people with early-stage appendix cancer.
In most cases, appendix cancer goes undetected until an appendectomy is already being performed for other reasons.
After any cancer diagnosis, it’s important to follow up regularly with your doctor to be sure there’s no recurrence of cancer.