Appendix cancer involves the rare malignancies of the vermiform appendix. Although, carcinoids are the most common tumours of the appendix, not all appendiceal carcinoids are malignant. Malignant features include size over 1 to 2 cm, presence in lymph nodes, or invasion of tissues adjacent to the appendix.
Adenocarcinomas are more common primary malignancies of the appendix than carcinoids. Despite this, adenocarcinomas originating in the appendix are rare and usually resemble colonic adenocarcinoma, microscopically. Primary lymphomas can occur in the appendix. Breast cancer, colon cancer, and tumours of the female genital tract may also metastasise to the appendix.
There are different types of tumours that can start in the appendix:
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, primarily, in either the GI tract or lungs, but may also occur in the pancreas, the testicles, or the 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, and is found during an examination or procedure performed for another reason.
Colonic-type adenocarcinoma accounts for about 10% of appendix tumours and usually occurs at the base of the appendix. This type of tumour looks and behaves like the most common type of 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, considered to be the most aggressive adenocarcinoma, 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.
Paraganglioma is a rare tumour that develops in the cells of the paraganglia, a collection of cells from the nerve tissue, that persist 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
Digestive disturbances, excessive flatulence
Loss of appetite, inability to eat a complete meal
Constipation and/or diarrhoea, 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. Rare in children, the average age at diagnosis is 40, for carcinoid tumours of the appendix.
In addition to a physical exam, the following tests may be used to diagnose appendix cancer:
A biopsy, the removal of a small amount of tissue for examination under a microscope, is required to make a definite diagnosis. The sample removed during a biopsy is analysed by a pathologist. However, most often, appendix cancer is found unexpectedly during or after abdominal surgery, owing to the lack of symptoms. 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. Sometimes, a contrast medium is injected into a patient's vein or given orally to provide better detail.
Magnetic Resonance Imaging (MRI)
An MRI uses magnetic fields, not X-rays, to produce detailed images of the body. A contrast medium may be injected into a patient's vein or given orally to create a clearer picture.
An ultrasound uses sound waves to create a picture of the internal organs.
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 these diagnostic tests are done, doctors review all of the results with the patient. If the diagnosis is cancer, these results also help the doctor describe the cancer; this is called staging.
Surgery is the removal of the tumour and the surrounding tissue during an operation. It is the most common treatment for appendix cancer. Most often, appendix cancer is low-grade and, therefore, slow-growing. Often it can be successfully treated with surgery.
Chemotherapy is the use of drugs to kill cancer cells, usually by killing their ability to grow and divide. Chemotherapy is given by a medical oncologist, a doctor who specialises in treating cancer with medication. For appendix cancer, chemotherapy is often used soon after surgery, 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 doctor who specialises in giving radiation therapy to treat cancer is called a radiation oncologist. 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 certain cases, a form of radiation called P32 may be recommended. In this procedure, radioactive Phosphorous is dissolved in a liquid and placed inside the body after surgery. P32 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.