There is no appendix cancer screening test. A colonoscopy looks at the colon, and it can reach the opening of the appendix, but it cannot see inside the appendix, which is where these cancers usually begin. That is why most of us were found by accident.

My husband David got lucky, and I do not use that word loosely. His tumor had grown out of his appendix and was pushing into his colon. During a colonoscopy, his doctor could actually see it. The doctor told us that normally you cannot see that far into that part of the colon, but nothing was in the way of the view that day. David’s GI doctor, the person who discovered the tumor, gave it to us as good news.

“Good news. It’s appendix cancer. A quick snip in outpatient surgery and you will be home the same day, cancer free.”

David’s GI doctor, the day he found the tumor

It did not turn out to be a quick snip. David was already stage 3B by the time it was found, and it took a right hemicolectomy, not a same-day outpatient procedure. He is alive and well now, under watchful surveillance. Lucky. And I still think about how different things might have been if it had been caught earlier, on a first colonoscopy, before it ever grew far enough to come into view.

That is the hard part. A colonoscopy did find David’s cancer. It just found it late, and only because the tumor had grown into a spot the scope happened to see. Nothing screened for it. Nothing was watching the appendix on purpose.

Why a colonoscopy usually misses appendix cancer

The appendix is a small, narrow, dead-end tube that branches off the colon. A colonoscopy travels through the colon and reaches the appendiceal orifice, which is the little opening where the appendix connects. That opening is the door. The scope reaches the door and looks right at it.

The door is as far as it goes. The appendix is too narrow and too closed off for a colonoscope to enter, so the inside of the appendix is never seen. Appendix cancer usually starts inside that tube, in the wall and the lining, in the exact place the scope cannot reach.

A colonoscopy can only catch it when the tumor has grown outward far enough to change the opening. Then a doctor might see a bulge at the orifice, mucus pushing out, or tissue that looks rough and bleeds easily. Those are later signs. Early disease shows nothing at the door. This is why the medical literature plainly says appendiceal cancer is rarely detected by colonoscopy. A normal colonoscopy is a colon test. It is not an appendix cancer screening test, and it was never built to be one.

There is no appendix cancer screening test

The colon has the colonoscopy. The breast has the mammogram. The cervix has the Pap test. The appendix has nothing. There is no appendix cancer screening test that catches it early in people who feel fine.

So it gets found the hard way. It turns up during surgery for what looked like appendicitis. It shows up on a scan ordered for something unrelated. It hides behind symptoms that look like a hundred more common things. This is true across the appendiceal cancers, including low-grade and high-grade mucinous neoplasms, goblet cell adenocarcinoma, signet ring cell, and the neuroendocrine tumors. Different subtypes, same blind spot.

Found by accident

Connie Zickler’s pain started in 2016. Her scans and bloodwork showed nothing clear. In 2018 a doctor told her she had ovarian cancer and operated, and she woke up to be told it was not cancer after all. In 2021 the pain came back hard. The scans again pointed at her ovaries. She went through months of needle biopsies that all came back negative while the disease kept spreading. It took a specialist at a cancer center recognizing the pattern almost immediately to finally name it. It was appendix cancer, and it had been appendix cancer the whole time. Five years passed between her first pain and the right diagnosis. Two of those years were spent chasing the wrong cancer.

Amy Jellison never had a symptom that pointed at her appendix. She had recurring urinary infections, heartburn, and nausea. A scan found a cyst on her ovary, and she was scheduled for a hysterectomy.

“During the hysterectomy, my gynecologist removed my appendix, noting it looked abnormal.”

Amy Jellison

That was the only reason it was caught. The biopsy came back as a low-grade appendiceal mucinous neoplasm that had already spread beyond the appendix. If that surgeon had not looked twice at an organ she was not even operating on, it would have kept growing quietly.

Colleen felt nothing at all. She was not in pain. Over months her abdomen swelled until she looked pregnant, and she was told it was weight gain and a slow metabolism. A scan finally sent her to the emergency room, where it was read as advanced ovarian cancer. It was not ovarian. It was a low-grade appendiceal mucinous neoplasm that had already spread through her abdomen.

“It all started quietly. I was completely asymptomatic, no pain, no discomfort.”

Colleen

Jeremy Kitzhaber is a veteran. His first symptoms came in his early 40s, not long after he left the service. He had never heard of appendix cancer, and the local doctor he first saw did not recognize it either. By the time it had a name it was stage 4, and he has been living with it for more than a decade. Sometimes the problem is not that the scope cannot reach it. Sometimes it is that no one in the room has ever seen this disease before.

“I didn’t even know this kind of cancer existed until it was me. My doctor didn’t know what it was either.”

Jeremy Kitzhaber

Colin Campbell is an offshore diver from a small island off the west coast of Scotland. At 47 he had real appendicitis, confirmed by his bloodwork and a CT scan. He expected the usual plan, remove the appendix and recover. Instead his surgeon pushed antibiotics and sent him home. Four months later, after the NHS refused him a second opinion, Colin borrowed money and paid privately to have his appendix taken out. Pathology found a ruptured low-grade appendiceal mucinous neoplasm. The cancer had been sitting inside the whole time. A small tumor in an inflamed appendix is nearly impossible to see on a scan, which is why for years a problem appendix was simply removed and examined. The operation was the safety net. The antibiotics cleared the infection and left the tumor behind.

“I was not misdiagnosed. I genuinely had appendicitis. What I was denied was the chance to be diagnosed with the tumor that caused it.”

Colin Campbell

Amy Moeller was diagnosed with pseudomyxoma peritonei in 2012, at 38, and lived years past it. When it came back more than a decade later, it was surveillance imaging that caught the recurrence, not a screening program. Even after you are a patient, staying ahead of this disease still depends on scans and watchful follow-up, because there is still no test that screens for it in the first place.

These are different people on completely different paths, and the same theme runs through all of them. Nobody was screened. Everybody was found by chance, by surgery, or by a doctor who happened to look closer. You can read more of these stories on the patient stories page, and the pattern repeats over and over.

What we can do until there is an appendix cancer screening test

I cannot hand you a screening test that does not exist yet. What I can tell you is that the way we get one is by showing the pattern. Right now the story of how appendix cancer gets found is scattered across thousands of individual patients who each felt alone and confused when it happened to them. When those stories sit together in one place, they stop being scattered and start being data.

That is what the Patient-Led Global Appendix Cancer Registry is for. It gathers our molecular, pathology, and diagnostic details so researchers can study appendix cancer as its own disease instead of a footnote to colon cancer. More than 1,500 of us across 52 countries are already part of this community. Every story we add makes the picture clearer for the person who gets diagnosed next.

So here is my ask. Tell us how your cancer was found. Add your details to the registry. We do this partly for ourselves, because we want better treatments in our own lifetimes. But we also do it for the people who come after us, so that one day appendix cancer gets caught before it becomes something a person has to battle for the rest of their life.

Common questions

Can a colonoscopy detect appendix cancer?

Sometimes, but not reliably. A colonoscopy can reach the opening of the appendix, but it cannot see inside the appendix where these cancers usually start. It tends to catch appendix cancer only after the tumor has grown out toward the opening, which is often late.

Is there a screening test for appendix cancer?

No. There is currently no appendix cancer screening test. Unlike colon, breast, or cervical cancer, there is no routine test that catches it early in people without symptoms.

How is appendix cancer usually found?

Most often by accident. It is commonly discovered during surgery for a suspected appendicitis, or on a scan ordered for an unrelated problem. Many people are misdiagnosed with other conditions first.

If my colonoscopy was normal, am I cleared of appendix cancer?

Not necessarily. A normal colonoscopy checks the colon. It does not rule out a tumor growing inside the appendix. If you have ongoing abdominal symptoms that no one can explain, it is reasonable to ask a specialist about the appendix specifically.