08/11/2026
The Basics
Appendix cancer, also known as appendiceal cancer, is a rare malignancy that originates in the appendix, a small tubular organ connected to the beginning of the colon occurs in less than 1% of all appendectomies. [see References: 1] The exact function of the appendix is unknown, but more recent studies suggest that it may house certain bacteria that aid in digestion and help replenish the digestive tract after a gastrointestinal illness.[2] It originates from a malignant, mucinous growth in the appendix, the small tubular organ connected to the colon. Because of its location and often subtle early presentation, these tumors cannot always be detected with a colonoscopy. The exact function of the appendix is unknown, but more recent studies suggest that it may house certain bacteria that aid in digestion and help replenish the digestive tract after a gastrointestinal illness.[2] Appendix cancers are very diverse and include several distinct types of tumors, ranging from mucinous neoplasms to goblet cell carcinomas and neuroendocrine tumors.
In addition to histologic tumor subtype, appendix cancers are also classified by “grade,” which describes how abnormal the cancer cells appear under a microscope and reflects how aggressive the tumor is. Low-grade tumors tend to grow more slowly, while high-grade tumors are more aggressive.
Appendix cancer most commonly presents as pseudomyxoma peritonei (PMP), a clinical syndrome characterized by accumulation of mucin and widespread peritoneal disease within the abdominal cavity. Mucin is a jelly-like substance that the body normally produces to protect the lining of the stomach, intestines, and the appendix. In some appendix cancers, tumor cells produce excess mucin which can cause the appendix to rupture, and lead to abdominal spread. PMP is classified as either a low-grade, less aggressive form, known as disseminated peritoneal adenomucinosis (DPAM) or low-grade mucinous carcinoma peritonei (LGMCP), or a more invasive form known as peritoneal mucinous carcinomatosis (PMCA) or high-grade peritoneal carcinoma peritonei (HGMCP).[3] Overall 10-year survival for PMP is approximately 32%,[4, 5] though outcomes vary significantly by tumor grade and completeness of surgical removal.
When detected early, many types of appendix cancer are highly treatable. Cytoreductive surgery and heated intraperitoneal chemotherapy (CRS/HIPEC) is considered the standard of care treatment for all types of advanced appendix cancers. CRS refers to the aggressive surgical removal of all visible tumors. HIPEC is the perfusion of heated chemotherapy throughout the abdominal cavity and is performed immediately following cytoreductive surgery.
https://www.abdominalcancers.org/appendix-cancer
