Appendix Cancer Sharply Rises Among GenX and Millennials

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On June 11, 2025

Cancer of the appendix, while rare, has been dramatically increasing among younger generations, making it part of a troubling trend of gastrointestinal cancers appearing more frequently at ages earlier than typically expected, new data shows.

An analysis of data from the National Cancer Institute published this week in the Annals of Internal Medicine found a sharp rise in appendix cancer (appendiceal adenocarcinoma) cases in the United States, especially among Gen X and millennials.

When looking at nearly 5,000 cases of appendix cancer, researchers noted that cancer incidence among Gen X adults was more than 3 times greater compared with a control group of adults born between 1941 and 1949. For millennials, the cancer rate was 4 times higher compared with the control group.

“It’s concerning that we’re seeing appendix cancer rates triple among Gen Xers and quadruple among older millennials,” says lead study author Andreana N. Holowatyj, PhD, an assistant professor of hematology, oncology, and cancer biology at Vanderbilt University Medical Center in Nashville, Tennessee.

“But I also think it’s important to emphasize the rarity of this disease overall and not spark any considerable alarm.”

Rising Appendix Cancer Rates Are Part of a Trend

The appendix is a small, tubular pouch located between the small and large intestine. Although its function in the gastrointestinal tract is not entirely clear, the organ is thought to store good bacteria that can help restore gut health after events such as diarrhea.

Annually, appendix cancer affects only about 1 or 2 people per one million, according to the National Cancer Institute.

But recent data show these cancer cases have been steadily climbing. One study found that overall incidence of malignant appendix tumors in the United States more than doubled from 2000 to 2016 — and the diagnosis increases were highest among younger age groups.

“This is not a pattern that’s just limited to cancers of the appendix — we’re seeing this trend across multiple cancers in the gastrointestinal tract,” says Dr. Holowatyj, whose lab focuses on early-onset cancers (those diagnosed before age 50). These early-onset GI cancers include colorectal, stomach, pancreatic, and esophageal.

Why Are More Young People Getting Gastrointestinal Cancers?

The chance of developing cancer rises steadily with age, with the highest cancer rates in adults 60 and older.

Because cancer has been considered more of an old person’s disease, the recent jump in gastrointestinal cancers among younger adults has been puzzling. Research as to why this is occurring has only recently begun, and so far researchers haven’t identified a clear reason for the trend.

Evidence suggests, however, that these gastrointestinal cancers may share similar modifiable risk factors — such as obesity, poor diet, alcohol consumption, and tobacco use, according to Ardaman Shergill, MD, an oncologist specializing in gastrointestinal cancers at UChicago Medicine.

“I speculate that risk-reducing strategies in other cancers, like not smoking, stopping or at least limiting alcohol, and regular exercise, may have beneficial effects in appendix cancer as well,” says Dr. Shergill, who was not involved in the study.

Holowatyj adds that genetics may also play a role, and her lab is working to better understand how various risk factors may contribute to the disease.

“I’m inspired by all of my patients who have battled appendix cancer and continue to battle appendix cancer as they try and help us understand what’s driving disease development and how we can reduce this burden over time,” she says.

What Are the Symptoms of Appendix Cancer?

Preventing appendix cancer is vital, as this disease can be especially difficult to diagnose in its early stages before the cancer has spread.

“Symptoms of appendix cancer are vague, nonspecific, and often overlap with other gastrointestinal or gynecologic cancers,” says Zachary J. Brown, DO, a surgical oncologist and assistant professor of surgery at the NYU Grossman Long Island School of Medicine in New York.

“Patients may experience nonspecific symptoms such as persistent abdominal pain, fatigue, or unexplained weight loss. As a result of the nonspecific symptoms and not being able to see this cancer on colonoscopy, appendix cancers are often found at a late stage,” Dr. Brown says.

Other potential symptoms of appendix cancer include:

Acute appendicitis (most cases of appendix cancer are discovered during surgery for appendicitis, which is painful inflammation of the appendix)
Abdominal bloating
Vague pain in the lower right abdomen
Pelvic discomfort
New hernias
Bowel obstruction
Changes in bowel habits
Ovarian masses

How Is Appendix Cancer Treated?

Surgery is the most common treatment option for appendix cancer, along with chemotherapy and other treatments.

“Often these are long surgeries needing many hours to complete,” says Shergill.

The prognosis for survival depends on the type of appendix cancer, the stage at diagnosis, and how far the cancer has spread.

The five-year survival rate for low-grade appendix tumors is between 67 to 97 percent. For more advanced appendix cancers, or those that have spread to other parts of the body, survival rates can be much lower.

“There is still so much to learn about this disease,” says Brown, who was not involved in the study. “A better understanding of the tumor biology, molecular characteristics as well as definitive risk factors for appendix cancers is essential. This will allow for improved therapies and potential earlier detection.”