3 reasons appendix cancer is hard to diagnose
April 03, 2026
Until about 15 years ago, appendix cancer was often lumped together with colon cancer. That’s because the appendix is technically part of the colon.
Today, though, doctors recognize appendix cancer as its own separate disease, with distinct genetic drivers at the molecular level that differ from those of colorectal cancers.
Even so, appendix cancer can still be difficult to diagnose. Why?
Here are three reasons gastrointestinal medical oncologist John Paul Shen, M.D., and gastrointestinal surgical oncologist Beth Helmink, M.D., Ph.D., shared during a recent episode of UT MD Anderson’s Cancerwise podcast.
1. Early-stage appendix cancer doesn’t cause any symptoms
The first reason appendix cancer is hard to diagnose is that, unlike the cancers of the gut, it doesn’t cause symptoms like pain, bleeding, nausea/vomiting or constipation.
“In some cases, an appendix tumor may cause appendicitis,” explains Shen. “Then, you would have pain and go to an emergency room. The problem is, it’s otherwise a very silent disease. So, unless a tumor is near the very tip of your appendix, you might not even know you have one until it’s already spread throughout your abdomen.”
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2. Colonoscopies can’t detect appendix cancer
Another reason appendix cancer is hard to diagnose? There’s currently no screening test for it. It can’t be detected by a colonoscopy, the recommended screening test for colorectal cancer.
“People come to me so frustrated sometimes, because their colonoscopy didn’t show anything,” notes Helmink. “What they don't realize is that the scope itself is bigger than the appendix. So, you can’t actually look inside of it.”
3. Appendix cancer is often misdiagnosed as ovarian cancer
Appendix cancer is also difficult to diagnose because its vague symptoms — such as bloating and abdominal discomfort — mimic those of ovarian cancer. It also spreads in the same way — through a liquid or gelatinous fluid that seeps between the abdominal organs.
“Many of our female patients are misdiagnosed as having ovarian cancer,” says Helmink. “That’s because a lot of these tumors spread to the ovaries. So, sometimes, people do have ovarian masses. They’re just coming from the appendix, not the ovary itself.
To hear the entire discussion between Helmink and Shen — including which patients make the best candidates for surgery, how molecular testing is sometimes making targeted therapy and immunotherapy a treatment option, and which well-established chemotherapy drug is making a comeback against high-grade mucinous appendix cancer — listen to the podcast.
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