What Is Appendix Cancer? Symptoms and Treatment

What Is Appendix Cancer?

Appendix cancer is cancer of the appendix, an extension located in the cecum, the part of the large intestine at the junction of the small and large intestines. Rare cancersinclude it. There are several different types of appendix cancer, and this cancer generally causes no symptoms in its early stages.

Note: The medical name of the appendix is "appendix vermiformis". It is a worm-shaped extension of the cecum. The cecum is the first part of the colon (large intestine). Appendix means "addition", and vermiformis means "worm-shaped"; it is a tubular, finger-like pouch approximately 5-10 cm long. The purpose of this organ is not fully known. People can live without their appendix without problems. Its most commonly known disease is the inflammatory condition called appendicitis .

We mentioned that appendix cancer is very rare; it affects, per 1 million people, 2 to 9 individuals. However, some studies from recent years suggest that appendix cancer incidence is tending to rise.

A recent retrospective study estimated that in 2000 the rate was, per 1 million, 6, rising in 2009 to, per 1 million, 10 people.

In this article, we discuss the types, symptoms, causes, risk factors, diagnosis, treatment and survival rates of appendix cancer.

What Are the Types of Appendix Cancer?

Some appendix tumors are benign, meaning they do not invade tissue and do not cause metastasis . Other tumors are malignant and therefore cancerous, meaning they invade or can spread to other organs.

An appendix tumor may be one of the following types:

• Neuroendocrine tumor
   Carcinoid tumor is another name for this type, which generally starts at the tip of the appendix and accounts for more than half of appendix cancers.
• Mucinous cystadenoma
  This is a benign tumor starting in mucoceles, areas of mucus-filled swelling or sacs in the appendix wall. A mucinous cystadenoma is benign and does not spread to other organs when it develops in an intact appendix. It is also known as a low-grade mucinous neoplasm.
• Mucinous cystadenocarcinoma
  This tumor type also starts in mucoceles but is malignant and may spread elsewhere. Of all appendix cancer cases, it accounts for approximately 20 percent.
• Colonic-type adenocarcinoma
  Of all appendix tumors, approximately 10 percentare adenocarcinomas, and they generally start at the base of the appendix when originating from this organ. They can spread to other organs and parts of the body.
• Goblet cell carcinoma
  Also known as an adenoneuroendocrine tumor, this tumor type has characteristics resembling both a neuroendocrine tumor and an adenocarcinoma. A goblet cell carcinoma can spread to other organs and may be more aggressive than a neuroendocrine tumor. 
• signet-ring cell adenocarcinoma
  A rare malignant tumor that is difficult to treat, signet-ring cell adenocarcinoma grows more quickly and is harder to treat than other adenocarcinomas.
• Paraganglioma
  This tumor type is usually benign. However, the medical literature has reported a rare case of malignant paraganglioma of the appendix.

What Are the Symptoms of Appendix Cancer?

Appendix cancer generally causes no symptoms in its early stages. It is usually diagnosed when it causes complaints or begins spreading to other organs. Doctors may also find this cancer while assessing a patient for a different condition.

The symptoms and complaints caused by appendix cancers usually depend on the tumor's effects. Appendix cancer can lead to the following conditions:

Pseudomyxoma peritonei

Some appendix tumors can cause pseudomyxoma peritonei (PMP), which occurs when the appendix ruptures and tumor cells leak into the abdominal cavity. Tumor cells secrete a protein gel called mucin that can build up in the abdominal cavity and continue to spread.

PMP can contain cancer cells leaking into the abdominal cavity. Without treatment, its accumulation can lead to digestive system problems and bowel obstructions. Mucinous cystadenomas and mucinous cystadenocarcinomas of the appendix can cause PMP.

Symptoms of pseudomyxoma peritonei include: 

• intermittent abdominal pain
• abdominal bloating and tightness 
• loss of appetite 
• feeling full after eating only a small amount 
• nausea or vomiting 
• constipation or diarrhea 
• inguinal hernia (groin hernia), containing mucus and more common in men

Appendicitis

Appendicitis, inflammation of the appendix, may be the first sign of appendix cancer. This is because some appendix tumors can block the appendix, trapping bacteria normally found in the intestines inside it.

The most common treatment for appendicitis is emergency surgery to remove the appendix. When the surgeon removes the appendix, a biopsy of the tissue may reveal that the person has appendix cancer.

The most important sign and symptom of appendicitis is abdominal pain:

• in the lower right abdomen, 
• worsening with movement or deep breaths 
• coming on suddenly and becoming worse. Appendicitis may also cause:
• abdominal swelling
• nausea or vomiting
• constipation or diarrhea

Not every type of appendix cancer causes appendicitis. For example, most neuroendocrine tumors form at the tip of the appendix, so they are unlikely to cause a blockage that could lead to appendicitis.

It is important to remember that someone diagnosed with appendicitis may have appendix cancer. Other factors, such as abdominal trauma and inflammatory bowel disease, can cause appendicitis. Many cases of appendicitis have no known cause.

Other Symptoms of Appendix Cancer

In some cases, people with appendix cancer may discover a hard mass in the abdomen or pelvic (groin) region. They may also have abdominal pain or swelling. In women, ovarian cancer (cancer of the ovaries) and appendix cancer may be confused, but it should be remembered that appendix cancer is very rare.

If the tumor in the appendix region is malignant (cancerous), cancer cells may grow on the surface of other abdominal organs and on the peritoneum (the lining of the abdominal cavity). This progression of disease is known as peritoneal carcinomatosis (peritonitis carcinomatosa) . If untreated, it may cause ileus (bowel obstruction) .

Appendix cancers generally do not spread to organs outside the abdominal cavity, except for signet-ring cell adenocarcinomas.

What Are the Causes and Risk Factors of Appendix Cancer?

Scientists have not yet fully clarified the causes of appendix cancers. No link has been found between appendix cancer and genetic or environmental causes of cancer .

Doctors generally believe appendix cancer affects men and women equally. Because it is rare in children, being an adult (older age)is the only known risk factor. Most patients with appendix cancer are diagnosed between the ages of 40 and 59.

How Is Appendix Cancer Diagnosed?

Appendix cancer is most often diagnosed incidentally after appendicitis surgery or when the tumor spreads to other organs and causes symptoms.

There is no appendix cancer-specific early detection screening technique . Similarly, blood tests are not a reliable indicator of appendix cancers.

A definitive diagnosis of appendix cancer is possible through microscopic examination of tumor tissue by a pathologist.

How Is Appendix Cancer Treated?

The two main treatments for appendix cancer are surgery and chemotherapy.

The most important factors in selecting appendix cancer treatment are: 

• tumor type
• the location and stage of the cancer (extent of spread) 
• the person's general health and any other diseases

If cancer has not spread beyond the appendix, surgery alone may be sufficient. If it has spread to other organs, the surgeon may remove affected organs to eliminate all cancer. This may include part of the intestines, ovaries or peritoneum.

The American Association of Endocrine Surgeons recommends that if an appendix cancer patient's tumor is larger than 2 cm, surgery should remove the right half of the colon and the appendix. This technique is known as right hemicolectomy .

For some patients, after surgery, adjuvant (protective) chemotherapy is also necessary.

HİPEK (HYperthermic PEritoneal Chemotherapy), the application of heated chemotherapy inside the abdomen during surgery, may be effective against appendix cancer that has spread to the abdominal lining and cavity.

With HİPEK, the surgeon fills the patient's abdomen with heated chemotherapy solution, continuing for approximately 1.5 hours. This technique may eliminate cancer cells doctors cannot see. The surgeon will perform HİPEK after removing the appendix and visible tumor cells. However, HİPEK requires substantial experience and is therefore recommended only for suitable/selected patients and only by experienced surgeons.

A new cancer treatment attracting attention in recent years and making significant contributions in many cancer types, immunotherapies, have not yet received approval for use in appendix cancers. However, the FDA has tissue-agnostic approval for MSI-high cancers. Therefore, for advanced appendix cancers that have exhausted available treatment options, if testing identifies MSI-high status, the immunotherapy pembrolizumab (Keytruda) may be considered.

Appendix Cancer Survival Rates

Survival rates for appendix cancer vary according to the tumor type, whether it has spread and where it is located.

Doctors use, to provide a predictive indication of how many people will live for at least 5 years after a cancer diagnosis, 5-year survival rates. However, it is very important to note that these figures are only estimates and that each person's outlook will differ.

According to the American Society of Clinical Oncology, the 5-year survival rates for neuroendocrine tumors of the appendix are: 

• If the tumor is smaller than 3 cm and has not spread, approximately 100 percent. 
• If the tumor is smaller than 3 cm and has spread to regional lymph nodes, around 78 percent. 
• Regardless of whether it has spread to other parts of the body, if the tumor is larger than 3 cm, around 78 percent. 
• If cancer has spread to other parts of the body, approximately 32 percent. 
• For goblet cell carcinoma, overall, 76 percent of people live for 5 years or longer following diagnosis.

Statistics are not available for other subtypes because this is a rare disease.

Appendix Cancer Summary

Appendix cancers are extremely rare and cause no symptoms in many people at an early stage. Doctors generally diagnose appendix cancers only when they begin to spread to other organs, meaning at advanced stages. An exception is incidental diagnosis after appendicitis surgery.

Because appendix cancer is very rare, many details about the disease remain unclear. Nevertheless, appendix cancer can be said to be one of the treatable cancers, and many patients have good outcomes with modern cancer treatments.