Appendix cancer, also known as appendiceal cancer, is a rare malignancy developing from the appendix, a small, finger-shaped pouch connected to the caecum of the large bowel/intestine. It sits on the lower right side of the abdomen, and has an unknown function within the body.
Appendix cancer is more common in women, and tends to be diagnosed between the ages of 40-60. However, anyone can develop this disease.
Types of Appendix Cancer
There are several types of appendix cancer, which are categorised by the types of cells they develop from.
Neuroendocrine Tumours (NETs)
Appendiceal NETs are a rare type of NET that develops in the appendix, however, they are the most common type of appendix cancer. These tumours often produce symptoms similar to those produced by an appendicitis, and are often diagnosed during surgery to remove the appendix (appendectomy). Appendiceal NETs are often found at the tip of the appendix, and can have a good prognosis.
Goblet Cell Carcinoma (GCC)
Goblet cell carcinomas (GCC) are rare neuroendocrine tumours that develop in the appendix. More specifically, they develop in goblet cells, which are responsible for mucus secretion and production.
GCCs demonstrate a unique combination of both neuroendocrine cells and adenocarcinoma cells, which are cancerous cells that develop from mucus-producing cells. They tend to be more aggressive than classic neuroendocrine tumours, but are classified and staged as carcinomas of the appendix.
For more information on GCCs, please refer to the Rare Cancers Australia Goblet Cell Carcinoma (GCC) page.
Mucinous Adenocarcinoma
Mucinous adenocarcinomas are the second most common type of appendix cancer that develop from the mucus-producing glands in the appendix. These tumours produce mucin, which is a jelly-like substance found in the mucus that lines some organs. This mucin production can cause cancer cells to metastasise to other parts of the body, most commonly the peritoneum (a membrane that surrounds many abdominal organs). Mucinous adenocarcinomas are often diagnosed at a late stage of disease, and may not have as good of a prognosis as other types of appendix cancer.
Pseudomyxoma Peritonei (PMP)
Pseudomyxoma peritonei (PMP) is a rare tumour that causes a build-up of mucin in the abdomen or pelvis. It is often found in the appendix, and is associated with conditions such as mucinous adenocarcinomas. However, PMP can also develop in other organs, such as the large bowel or the ovary. While this type of cancer develops very slowly, it can put pressure onto nearby organs which may cause problems. PMP can have a good prognosis when caught early.
Colonic-type Adenocarcinoma
Colonic-type adenocarcinomas are rare types of appendix cancer that are often found in the base of the appendix. They behave similarly to colorectal adenocarcinomas, which is the most common type of bowel cancer. Unlike other types of appendix cancer, colonic-type adenocarcinoma is slightly more common in men. While this type of cancer can be aggressive, it can have a good prognosis when caught early.
Signet Ring Cell Adenocarcinoma
Signet ring cell adenocarcinomas are very rare types of appendix cancer that are also found in mucus-producing cells in the appendix. However, these cells look distinctly different under the microscope due to unusually large cytoplasmic vacuoles that push the nucleus to the edge of the cell, forming a signet-ring shape. This type of cancer is often diagnosed late, and may not have as good of a prognosis as other types of appendix cancer.
Treatment
If an appendix cancer is detected, it will be staged and graded based on size, metastasis (whether the cancer has spread to other parts of the body) and how the cancer cells look under the microscope. Staging and grading helps your doctors determine the best treatment for you.
Cancers can be staged using the TNM staging system:
- T (tumour) indicates the size and depth of the tumour.
- N (nodes) indicates whether the cancer has spread to nearby lymph nodes.
- M (metastasis) indicates whether the cancer has spread to other parts of the body.
This system can also be used in combination with a numerical value, from stage 0-IV:
- Stage 0: this stage describes cancer cells in the place of origin (or ‘in situ’) that have not spread to nearby tissue.
- Stage I: cancer cells have begun to spread to nearby tissue. It is not deeply embedded into nearby tissue and had not spread to lymph nodes. This stage is also known as early-stage cancer.
- Stage II: cancer cells have grown deeper into nearby tissue. Lymph nodes may or may not be affected. This is also known as localised cancer.
- Stage III: the cancer has become larger and has grown deeper into nearby tissue. Lymph nodes are generally affected at this stage. This is also known as localised cancer.
- Stage IV: the cancer has spread to other tissues and organs in the body. This is also known as advanced or metastatic cancer.
Cancers can also be graded based on the rate of growth and how likely they are to spread:
- Grade I: cancer cells present as slightly abnormal and are usually slow growing. This is also known as a low-grade tumour.
- Grade II: cancer cells present as abnormal and grow faster than grade-I tumours. This is also known as an intermediate-grade tumour.
- Grade III: cancer cells present as very abnormal and grow quickly. This is also known as a high-grade tumour.
Once your tumour has been staged and graded, your doctor may recommend genetic testing, which analyses your tumour DNA and can help determine which treatment has the greatest chance of success. They will then discuss the most appropriate treatment option for you.
Treatment is dependent on several factors, including location, age, stage of disease and overall health.
Treatment for appendix cancer may include:
- Surgery, potentially including:
- Appendectomy (complete removal of the appendix).
- Hemicolectomy (removal of the portion of the small bowel next to the appendix).
- Cytoreductive surgery (also known as CRS) (surgery to remove all visible tumour from the abdominal cavity. Part of the bowel is often removed, and potentially other abdominal and/or reproductive organs).
- Peritonectomy (removal of the peritoneum).
- Chemotherapy, potentially including:
- Local chemotherapy.
- Systemic chemotherapy.
- Heated intraperitoneal chemotherapy (HIPEC).
- Early post-operative intraperitoneal chemotherapy (EPIC).
- Radiation therapy.
- Clinical trials.
- Palliative care.
For more information on the treatment options, please refer to the Rare Cancers Australia treatment options page.
Risk factors
Because of how rare appendix cancers are, there has been limited research done into the risk factors of this disease.
Early symptoms
The symptoms of an appendix cancer often vary by subtype.
General Symptoms of Appendix Cancer
The general symptoms of appendix cancer include:
- Abdominal pain in the lower right quadrant (often caused by an inflammation of the appendix, known as an appendicitis).
- Gradual increase in waist size.
- Build-up of fluid in the abdomen (also known as ascites).
- Bloating.
- Changes in bowel habits, potentially including constipation or diarrhea.
- Hernia.
- Ovarian mass/lump.
- Nausea and/or vomiting.
- Feeling full after eating little food.
Patients with mucinous adenocarcinomas, PMP, colonic-type adenocarcinomas, or signet-ring adenocarcinomas rarely experience additional symptoms to the ones listed.
Symptoms of Appendix NETs & Goblet Cell Carcinomas
In addition to the general symptoms, patients with an appendiceal NET or a GCC may also experience the following symptoms:
- Bowel obstruction (blockage of the bowels).
- Abdominal lumps.
- Gastrointestinal bleeding.
- Intussusception (part of the intestine slides into another part of the intestine).
Not everyone with the symptoms above will have cancer, but see your general practitioner (GP) if you are concerned.
Diagnosis/diagnosing
If your doctor suspects you have an appendix cancer, they may order the following tests to confirm the diagnosis and refer you to a specialist for treatment.
Physical examination
Your doctor will collect your overall medical history, as well as your current symptoms. Following this, they may examine your body to check for any abnormalities.
Imaging & blood tests
The doctor will take images of your body using magnetic resonance imaging (MRI), a computed tomography scan (CT scan), x-rays, bone scan and/or positron emission tomography (PET scan), depending on where it is suspected the cancer is. The doctor may also look at other parts of the body and looks for signs of metastasis. Additionally, a blood test may be taken to assess your overall health and help guide treatment decisions.
Diagnostic Laparoscopy
A diagnostic laparoscopy is used for conditions that cannot be confirmed by scans and tests alone. A laparoscopy involves inserting a thin tube with a light and a camera attached (laparoscope) into the abdomen via an incision. This procedure is performed under general anaesthetic, and is often performed as a day procedure.
Biopsy
Once the location of the cancer has been identified, the doctor will perform a biopsy to remove a section of tissue using a needle. In most cases, this will be done by a core-needle biopsy, which involves a larger, hollow needle being inserted into a small incision above the area to be biopsied. Once a sample has been removed, it will be sent to a lab and analysed for cancer cells.
Prognosis (Certain factors affect the prognosis and treatment options)
While it is not possible to predict the exact course of the disease, your doctor may be able to give you a general idea based on the rate and depth of tumour growth, susceptibility to treatment, age, overall fitness, and medical history. Generally, early-stage appendix cancers have a better prognosis and survival rates. However, if the cancer is advanced and has spread, the prognosis may not be as good and there may be a higher risk of cancer recurrence. It is very important to discuss your individual circumstances with your doctor to better understand your prognosis.
References
Some references are to overseas websites. There may be references to drugs and clinical trials that are not available here in Australia.