Appendix Cancer - Types, Symptoms, Risk Factors, Diagnosis, Treatment, and Prognosis

What Is an Appendix?

An appendix is an organ that is found near the intestine. It is situated in the lower right part of the abdomen. Many researchers say that the appendix is an organ that has no useful function or very few functions. Other medical reports suggest that the appendix plays an important role in maintaining the gut health of the individual. In addition to this, it can also contribute to the functioning of the lymphatic system. It is approximately four inches long and attaches to the intestine. There are higher possibilities for the appendix to get infected and result in a condition called appendicitis.

What Is Appendix Cancer?

Cancer is an abnormal and disastrous growth in any part of the healthy tissue. The tremendous growth might decrease the functioning of the cells. When the abnormal cells outweigh the normal cells, it might result in the formation of a tumor or cancer. It can be benign or malignant according to the cells and tissues involved. A type of cancer that originates in the cells of the appendix is known as appendix cancer. It is also known as appendiceal cancer. It is a very rare type of cancer. Less than 100,000 patients have been reported to have appendix cancer in the United States of America.

What Are the Types of Appendix Cancer?

There are different types of appendix cancer:

1. Mucinous Adenocarcinoma of the Appendix - The mucinous adenocarcinoma can affect both the male and female gender. It can affect people who are more than 60 years of age. The adenocarcinoma is classified as high-grade and low-grade types.

2. Colonic-Type Adenocarcinoma - Only ten percent of the cancers belong to this category. It might resemble colon cancer. Men are more commonly affected by this type of cancer than women. Aged people have a higher possibility of occurrence.

3. Neuroendocrine Carcinoma - The other name for neuroendocrine carcinoma is known as carcinoid tumor. These cells are formed within the walls of the bowel. Most of the appendix cancers belong to this category. This type of cancer has a severe potential to spread and can be treated well with surgical options.

4. Goblet Cell Adenocarcinoma - Goblet cells are found in the respiratory tract and intestinal tract. In this type of cancer, the goblet cells are affected.

5. Signet Ring Cell Adenocarcinoma - Signet ring cell adenocarcinoma is the most aggressive of all the types. It is usually in association with the mucinous adenocarcinoma and colonic-type adenocarcinoma.

6. Paraganglioma - Paraglioma is a type of appendix tumor that can affect the nervous tissues. Paraganglia are found almost near the adrenal glands. Many blood vessels and nerves that are seen near the head and neck region are involved.

7. Appendiceal Mucoceles - Mucoceles refers to the sacs or the swelling that are found on the walls of the appendix. Mucinous cystadenomas and mucinous cystadenocarcinomas are the two variants of appendiceal mucoceles. Mucinous cystadenomas are similar to the interstitial polyps, and they do not spread. It is usually a benign condition. Mucinous cystadenocarcinoma is a malignant type and severely involves other organs.

How Is Appendix Cancer Staging and Grading Performed?

The TNM staging for appendiceal malignancies has undergone significant revisions in the past eight years, with several modifications introduced in the eighth edition compared to the previous seventh edition. While appendix cancers were categorized separately from colorectal cancers in the seventh edition, the eighth edition includes notable changes:

• Introduction of low-grade appendiceal mucinous neoplasms as T in situ.

• Expansion of T4 tumor definitions to include tumors with visceral peritoneal perforation indexes, as well as those with mucin presence on the serosal layer of the appendix or mesoappendix.

• Introduction of a similar concept to colorectal TNM classification, categorizing any evidence of tumor deposits (including satellite lesions in the subserosal layer) without metastatic lymphadenopathy as N1c.

• The inclusion of a sub-category M1c (non-peritoneal metastasis) was made, whereas the specific classification of pseudomyxoma peritonei was removed from M1a.

Stage Classification -

• Appendiceal carcinomas are divided into two primary subtypes: mucinous and nonmucinous. The histological grading includes G1 (grade 1) to G3 (grade 3) grades, with particular emphasis on poorly differentiated appendiceal carcinomas, especially in metastatic mucinous appendiceal carcinomas.

• Additionally, two subcategories (intraperitoneal acellular mucin and intraperitoneal grade 1 tumor) have been added to stage IVA.

What Are the Symptoms of Appendix Cancer?

The symptoms of appendix cancer are:

• Hernia.

• Bloated abdomen.

• Discomfort in the lower right abdomen.

• Severe abdominal pain.

• Obstruction of the bowel.

• Ovarian masses.

• Diarrhea.

The malignant form of appendix cancer develops on the surface of the spleen, uterus, liver, ovaries, and peritoneum.

What Are the Risk Factors Associated With Appendix Cancer?

The risk factors associated with appendix cancer are:

• Atrophic Gastritis: It is an inflammation in the lining of the stomach.

• Pernicious Anemia: Pernicious anemia refers to the deficiency of vitamin B-12.

• Zollinger-Ellison Syndrome: It is a rare condition in which the digestive tract is affected. In this condition, the formation of tumors called gastrinoma might occur.

• Smoking.

• Having a family history of appendix cancer or multiple endocrine neoplasia type 1 (MEN1) disorder.

What Is the Pathophysiology Behind Appendix Cancer?

Blockage of the appendiceal lumen by cancerous cells results in inflammation, venous congestion, and subsequent infection of the appendix. In cases of mucinous tumors of the appendix, there might be an enlargement of the appendix due to the blockage caused by mucous-filled sacs. These mechanisms are responsible for the most common clinical presentation of this condition, which is acute appendicitis.

How Is Appendix Cancer Diagnosed?

Appendix cancer does not produce any symptoms in the initial stages. It might accidentally be revealed during an imaging session for other conditions, such as appendicitis. Sometimes doctors identify appendix cancer after the complete removal of the appendix.

Imaging techniques like MRI (magnetic resonance imaging), CT (computed tomography), and ultrasound procedures can be helpful. Computed tomography is the most preferred scan for most patients. For more precise images, magnetic resonance imaging is recommended by doctors. Blood tests are mostly not helpful for appendix cancer. In some cases, a biopsy is recommended by the doctor where the sample tissue is collected from the involved site and sent for microscopic diagnosis. Most reliable results can be obtained with this technique.

What Are the Treatment Options for Appendix Cancer?

The treatment is planned according to the following criteria:

1. Any other underlying health conditions of the individual.

2. Family history of the patient.

3. Type of cancer involvement.

4. Spreading of cancer.

If the cancer involvement is seen only in the appendix, then minor surgery is sufficient to cure the condition. If cancer has spread to other regions, then surgery is required to remove the cancerous tissue from that site. This might commonly include ovaries, peritoneum, and intestines.

The American Association of Endocrine Surgeons suggests a hemicolectomy in which the right half of the colon is removed. This method is preferred if the size of the cancer is more than two centimeters.

What Are the Complications Associated With Appendix Cancer?

• Pseudomyxoma peritonei (PMP) is characterized by the growth of mucinous-producing cancerous cells in the peritoneal cavity, leading to the accumulation of mucinous fluid. PMP often presents as the initial stage for most patients and is categorized based on grade.

• Disseminated peritoneal adenomucinosis (DPAM), associated with low-grade appendiceal mucinous neoplasm (LAMN), typically exhibits fewer mitotic figures and simple epithelial cells. On the other hand, high-grade peritoneal mucinous adenocarcinomatosis (PMAC) is usually linked with mucinous adenocarcinoma.

• In the presence of metastatic disease, adhesions, and intestinal obstruction commonly occur. Metastasis to the ovaries and retroperitoneum, as well as the rare complication of hydroureteronephrosis, may occur.

How Is the Prognosis for Appendix Cancer?

The prognosis for appendix cancer is predicted by the American Society for Clinical Oncology, where the average age is estimated to be around five years. This estimation of five years is grouped according to the following:

• If the cancer is less than three centimeters without any other site involvement or spreading, the prognosis is 100 percent.

• If the cancer is less than three centimeters and is spreading, the prognosis is 78 percent.

• If cancer is more than three centimeters, the prognosis is 78 percent.

• In cases of severe involvement of other sites, the prognosis is only 32 percent.

Conclusion:

Appendix tumors are rare, but more than half of cases do not show symptoms, and one-third are already spread when diagnosed, which makes outcomes worse. So, it is important for healthcare teams to be careful and communicate well, especially if patients have certain risk factors. This helps reduce complications and deaths. Support from palliative care teams, social workers, and case managers is also important in caring for these patients.