Appendix Cancer is NOT the Same as Colorectal Cancer and Here’s Why

Appendix Cancer is NOT the Same as Colorectal Cancer and Here's Why

March is colorectal cancer awareness month. Colorectal cancer is the third most common cancer in the US, and the second leading cause of cancer death. It affects men and women of all racial and ethnic groups, and is most often found in people 50 years or older although incidence in those younger than 50 is on the rise.[1].

Appendix cancer is very rare and often misunderstood, misdiagnosed, and has a  significant lack of awareness, including among many physicians. Appendix cancer is similar in some respects to colorectal cancer, particularly in that early-onset incidence is rising in both diseases (incidence rates of individuals of all ages with appendix cancer have risen 232% between 2000 and 2016 in the United States). However, appendix cancer is a distinct disease. Widespread sharing of correct information facilitates a more meaningful understanding about this rare disease.

“Appendix cancer falls under the same umbrella as colorectal cancer.”


Appendix cancer is its own type of cancer. It’s a rare cancer and it’s unlike any other. Appendix cancer is cancer that starts in the cells lining the inside of the appendix. There are a number of different types of cancers of the appendix. The different types are determined by which type of cells in the appendix become cancerous and what the cells look like under the microscope. The different types are associated with different behaviors (i.e. likelihood of spreading to other organs or other parts of the body, rate of growth, ability to be completely removed with surgery etc.) and therefore the types of treatment that are offered. Foundational genetic research funded by ACPMP in 2011 and 2012 led to a series of research studies proving that appendix cancer is genetically distinct from colorectal cancer.

“Since appendix cancer is treated with the same chemotherapies as colorectal cancer, I can see a colorectal cancer specialist for appendix cancer.”


Some surgical oncologists that treat colorectal cancer may also specialize in appendix cancer, but not all colorectal surgeons know how to treat appendix cancer or are qualified to do so. When searching for a specialist to treat appendix cancer and/or PMP, patients should be aware that research studies have concluded that centers offering the CRS/HIPEC procedure, the standard of care for metastasized mucinous appendiceal cancer, reach the peak of the learning curve only after the center has completed 130140180, or even more than 200 of these procedures. Not all patients will need CRS/HIPEC, but the physicians who perform it are the ones most familiar with appendix cancer and considered specialists. For more information on how to find and select a specialist, please visit our Find a Specialist resource.

“Colonoscopies are a reliable diagnostic tool for detecting appendix cancer.”


When detected early through colonoscopy screening, colorectal cancer is one of the most preventable and treatable forms of cancer, and we encourage all adults to keep up to date with regular colon cancer screenings[2]. Unfortunately, appendix cancer does not typically invade the inside of the colon. Therefore, appendix cancer will not always be seen during a colonoscopy. There are no presently known genetic, familial or environmental factors known to cause appendix cancer.  There are also no known ways to prevent appendix cancer.

The actual diagnosis of appendiceal cancer cannot be made until a tumor specimen is examined by a pathologist, usually following diagnostic tests consisting of CT scans, MRIs, and/or tumor marker tests. Final diagnosis is frequently accomplished at the time of appendectomy for appendicitis, surgery for an intestinal blockage or presumed ovarian cyst or cancer, hernia repair, or through a diagnostic tumor biopsy performed for an abnormal clinical or radiographic finding such as a palpable tumor or tumors seen on an imaging study.

“Since my appendix cancer went to my colon, it is now colon cancer.”


Like any form of cancer, the origin of the cancerous tumor determines the type of cancer. If the cancer originated in the appendix, it is appendiceal cancer. Like colorectal cancer that has metastasized to the liver, it is not then referred to as liver cancer, it is still colorectal cancer. Appendix cancer can metastasize to other surfaces of organs in the abdomen. Appendiceal cancers can metastasize to the colon, rectum, pancreas, liver, small bowel, gallbladder, ovaries, uterus, and others.


With any cancer diagnosis, it’s essential to do your own research and to educate yourself, but especially with a rare cancer. Knowledge is power and you are your own best advocate! The Appendix Cancer Pseudomyxoma Peritonei Research Foundation is here as a resource. If a patient has just been diagnosed, it’s important to learn about appendix cancer and PMP as well as first steps, to help guide decision-making and care. Remember that while rare, you are not alone.