Appendix is part of the digestive system and is classified as a vestigial organ. This pouch shaped organ is below the lower side of the abdomen and hangs down from the colon. It is considered as part of the gastrointestinal (GI) tract. Appendix cancer occurs when healthy cells in the appendix have abnormal growth giving rise to tumour. The tumour can either be benign (restricted to the appendix) or malignant (spread in other part of the body).
It is difficult to catch appendix cancer early and there are types which can be detected if the patient happens to be treated for appendicitis (inflammation of the appendix).
The cancer can be classified as Localized (affecting the colon, rectum, small intestine or stomach), Regional (affecting nearby tissue and lymph nodes) or Metastatic (spread to other parts of the body).
One of the rare forms of malignancies of appendix cancer involves the vermiform appendix (a finger-like, blind-ended tube). Although appendiceal carcinoids (a slow growing tumour) are quite common in the appendix, not all such carcinoids are malignant. Malignant features include size over 1 to 2 cm, presence in lymph nodes and invasion of tissues adjacent to the appendix.
Adenocarcinomas are more common primary malignancies of the appendix than carcinoids. Adenocarcinomas in the appendix usually resemble colonic adenocarcinoma. Primary lymphomas can occur in the appendix. Breast cancer, colon cancer, and tumours of the female genital tract may also spread to the appendix.
The types of Adenocarcinomas are:
Mucinous Adenocarcinoma: It begins in the appendix and produces mucin (a jelly-like substance that tends to spread cancerous cells to other parts of the body). These tumours are discovered after they have spread to the peritoneum (the lining of the abdominal cavity).
Goblet Cell Carcinoids: It is a less common tumour where it behaves quite similarly to mucinous adenocarcinoma. They are aggressive compared to carcinoid tumour. Patients above the age of 50 have a higher probability of getting this type of adenocarcinoma.
Other different types of tumours that can start in the appendix which includes:
Carcinoid Tumour: A carcinoid tumour starts in the hormone-producing cells that are normally present in small amounts in almost every organ of the body. A carcinoid tumour starts either in the GI tract or lungs or in the pancreas, the testicles and ovaries. An appendix carcinoid tumour most often occurs at the tip of the appendix. Approximately 66% of all appendix tumours are carcinoid tumours. It usually shows no symptoms and goes unnoticed until it has spread to other organs. Neuroendocrine tumours are classified under carcinoid tumours since it is difficult to detect and originates from the hormone producing cells.
Colonic-type Adenocarcinoma: Otherwise known as intestinal type adenocarcinoma, it accounts for about 10% of appendix tumours and usually occurs at the base of the appendix. This type of tumour looks and behaves like colorectal cancer. It often goes unnoticed and a diagnosis is frequently made during or after surgery for appendicitis.
Signet-ring Cell Adenocarcinoma: Signet-ring cell adenocarcinoma is considered to be the most aggressive adenocarcinoma. It is very rare and also the most difficult to treat. It usually occurs in the stomach or the colon and can cause appendicitis when it develops in the appendix. An appendectomy (surgical operation to remove vermiform appendix) is performed.
Paraganglioma: Paraganglioma is a rare tumour that develops in the cells of the paraganglia, a collection of cells from the nerve tissue that exists in small deposits after foetal development. It is found near the adrenal glands and some blood vessels and nerves. This tumour is usually considered benign and is often successfully treated with complete surgical removal. Paraganglioma is very rare outside of the head and neck region.
The symptoms of appendix cancer may include:
- Pain in the lower right quadrant
- Feeling bloated
- Abdominal distension
- Digestive disturbances and excessive flatulence
- Loss of appetite and inability to eat a complete meal
- Constipation, diarrhoea and shortness of breath
- The appearance of a hernia
Although risk factors often influence the development of cancer most do not directly cause cancer. Causes of appendix cancer are unknown and no avoidable risk factors have been identified. Age may raise a person’s risk of developing appendix cancer. It is however rare in children and the average age at diagnosis is 40 years.
In the initial stages, the doctors can conduct a physical examination by applying gentle pressure on the area. When the pain is released, the pain can feel worse. This could signal a possible abnormality in the appendix. Apart from it, the other tests to diagnose appendix cancer include:
A biopsy is conducted through the process of removing a small amount of tissue for examination under a microscope. The sample removed during a biopsy is analysed by a pathologist. Appendix cancer is often found unexpectedly during or after abdominal surgery. If cancer is suspected at the time of surgery, the doctor will remove a portion of the colon and surrounding tissue for examination. The cancer is diagnosed after the pathologist has processed and reviewed the tissue under the microscope.
Computed Tomography (CT or CAT) Scan:
A CT scan creates a three-dimensional picture of the inside of the body with an X-ray machine, which a computer then combines into a detailed, cross-sectional view that shows any abnormalities or tumours. A CT scan can also be used to measure a tumour’s size.
Magnetic Resonance Imaging (MRI):
An MRI uses magnetic fields to produce detailed images of the body. A contrast medium may be injected into a patient’s vein or given orally to get a clearer picture.
An ultrasound uses sound waves to create a picture of the internal organs. It gives a clearer picture on stage of the cancer.
Radionuclide scanning (OctreoScan):
In this, small amount of a radioactive, hormone-like substance that is attracted to a carcinoid tumour is injected into a vein. A special camera is then used to show where the radioactive substance accumulates. This procedure is useful in detecting the spread of a carcinoid tumour, especially to the liver.
After the completion of various diagnostic tests, the results are reviewed. If the diagnosis confirms a cancer, these results help in the staging of the cancer and the possible prognosis.
A tumour removal surgery is performed as part of the treatment. A surgery is performed to remove the appendix tumour and the surrounding tissues affected by it. It is the most common treatment option for appendix cancer. Most often, appendix cancer is low-grade and slow-growing. Often it can be successfully treated with surgery.
Chemotherapy is the use of drugs to kill cancer cells by killing their ability to grow and divide. It is often used soon after surgery during the advanced stages, when cancer is found outside the appendix region.
Radiation therapy is the use of high-energy X-rays or other particles to kill cancer cells. A radiation therapy regimen usually consists of a specific number of treatments given over a set period of time.
Radiation therapy is rarely used in the treatment of appendix cancer. In this procedure, an isotope is dissolved in a liquid and placed inside the body after surgery. It delivers strong radiation therapy to a specific area through a tube inserted in the abdomen. Because the radioactivity disappears quickly (within a few hours), there is no need to remove the substance from the abdomen after treatment. Side effects from radiation therapy may include fatigue, mild skin reactions, upset stomach, and loose bowel movements. Most side effects go away soon after treatment is finished.