Appendix cancer
Appendix cancer refers to malignant tumors that develop in the appendix, a small, tube-like structure attached to the large intestine. Though its exact function remains unclear, it may play a role in the immune system. Appendiceal tumors are classified as part of the broader category of colorectal and gastrointestinal cancers, with the most common types being carcinoid tumors, mucinous cyst adenocarcinoma, and colonic-type adenocarcinoma. Symptoms often mimic those of appendicitis, including abdominal pain, fever, and nausea, and many patients remain asymptomatic until the cancer is advanced. Diagnosis typically occurs incidentally during surgery for other conditions, as there are no standard screening tests. Treatment generally involves surgical removal of the tumor and affected tissues, potentially combined with intraoperative chemotherapy to target any remaining cancer cells. The prognosis for patients with appendix cancer varies significantly based on tumor type, extent of spread, and treatment efficacy. While no definitive prevention methods exist, lifestyle changes such as a healthy diet and exercise may lower the risk of developing related colorectal cancers.
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Appendix cancer
Also known as: Carcinoid tumor, colonic adenocarcinoma, mucinous cyst adenocarcinoma, signet-ring cell adenocarcinoma
Related conditions: Appendicitis, peritoneal carcinomatosis, disseminated peritoneal adenomucinosis
Definition: Appendix cancer is a cancerous tumor in the appendix, the pouchlike, thin tube with a closed end that is located in the lower right quadrant of the abdomen. The appendix, also called the vermiform appendix because its appearance is wormlike, is attached to the cecum, the first section of the large intestine, close to where it joins with the small intestine. It is not known to have a significant function in the body but may play a role in the immune system.
Cancerous tumors that originate in the appendix are part of the larger grouping of colorectal cancers or gastrointestinal cancers. Types of appendix cancer include carcinoid tumor, mucinous cyst adenocarcinoma, colonic-type adenocarcinoma, and signet-ring cell adenocarcinoma.
Risk factors: Because appendix cancer is not common, no specific risk factors have been identified. However, risk factors for colorectal cancers in general include a diet high in red meat and low in fiber, lack of exercise, obesity, high alcohol intake, family history of colorectal cancer, and cigarette smoking.
Etiology and the disease process: The cause of appendix cancer is unknown. It often goes undiagnosed until it causes appendicitis or the appendix ruptures. In a majority of patients, appendix tumors spread in a process called peritoneal seeding, in which multiple, initially small, tumors are produced throughout the abdominal cavity. Low-grade tumors grow more slowly and are generally less invasive, whereas high-grade tumors are faster growing and considerably more invasive.
Incidence: Cancer that starts in the appendix, or primary appendix cancer, is uncommon. Therefore, these cancers are usually included in the statistical data for colorectal cancer and actual incidence rates are not available. One estimate is that primary appendix cancer accounts for about 0.5 percent of intestinal cancers.
About 66 percent of appendix tumors are carcinoid tumors, 20 percent are mucinous cyst adenocarcinoma, and 10 percent are colonic-type adenocarcinoma. Signet-ring cell adenocarcinoma, which is rare, is an aggressive cancer that is more difficult to treat than other adenocarcinomas.
Symptoms: People with appendix cancer may not experience symptoms until the disease is far advanced. The first reported symptoms are typically those of appendicitis, which include fever, pain in the lower right quadrant of the abdomen, nausea, and vomiting. Other symptoms may include bowel changes, abdominal bloating, pelvic pain, infertility, and an increase in waistline size, with possible navel protrusion. Some people experience no symptoms at all, and the cancer is found incidentally during surgery for another condition such as ovarian tumors.
Screening and diagnosis: There are no screening tests for appendix cancer. Most often it is found during surgery for another abdominal condition, either when a biopsy is performed on the tissue that has been removed or when the surgeon observes abnormalities or tumors in the abdomen. Computed tomography scanning, magnetic resonance imaging, and ultrasound can be performed if appendix cancer is suspected or to determine the extent of the cancer’s spread. Radionuclide scanning is performed to determine the spread of a carcinoid tumor.
No standard staging system exists for appendix cancer. Instead, appendix tumors are usually classified by whether the cancer is confined to the appendix or has spread and how far: to distant organs or only to nearby tissues.
Treatment and therapy: The treatment of appendix cancer depends on the type of tumor, its size, and whether the cancer has spread. Surgery to remove the tumor along with nearby blood vessels, lymph nodes, and part of the large bowel is the most common treatment for tumors that are low grade and slow growing. For higher-grade, more aggressive tumors and tumors that have seeded the abdomen, the surgeon removes as much of the cancer in the abdomen as possible. When complete, it means that all visible tumors were removed; when incomplete, it means that some tumors could not be removed. This surgery is typically combined with intraoperative hyperthermic intraperitoneal chemotherapy; a high concentration of a chemotherapy solution is instilled in the abdomen during surgery. The solution, heated to just above normal body temperature, has been found to be effective because it destroys cancer cells and tumors that are too small to be seen and also because it can reach all surfaces in the abdomen. Postoperative intraperitoneal chemotherapy is also used in some cases.
Prognosis, prevention, and outcomes: The prognosis for appendix cancer varies greatly and depends on several factors, including the type of tumor, whether it has spread, and how it is treated. Complete cytoreductive surgery combined with intraoperative hyperthermic intraperitoneal chemotherapy has been found to be effective in increasing survival rates, especially with mucinous cyst adenocarcinoma. Appendix cancer has no known method of prevention, although increased exercise, a high-fiber and low-fat diet, smoking cessation, and weight loss if overweight or obese may reduce risk.
Bibliography
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Carmignani, C. P., and P. H. Sugarbaker. “Synchronous Extraperitoneal and Intraperitoneal Dissemination of Appendix Cancer.” European Journal of Surgical Oncology 30.8 (2004): 864–68. Print.
Holland, Jimmie C., and Sheldon Lewis. The Human Side of Cancer. New York: HarperCollins, 2000. Print.
Ruoff, Carl, et al. "Cancers of the Appendix: Review of the Literatures." ISRN Oncology (2011): 1–6. Web. 17 Oct. 2014.
Shepherd, Neil A., et al., eds. Morson and Dawson's Gastrointestinal Pathology. 5th ed. Chichester: Wiley, 2013. Print.
Sugarbaker, Paul H. “New Standard of Care for Appendiceal Epithelial Neoplasms and Pseudomyxoma Peritonei Syndrome?” Lancet Oncology 7.1 (2006): 69–76. Print.