Cases of appendix cancer appear to be rising sharply among younger adults, according to a new study.
The research, published June 10 in Annals of Internal Medicine, specifically found that diagnoses of the little-known disease tripled among Generation X and quadrupled among older millennials in the United States.
This study provides data to back up “a general sense that the diagnosis has increased,” Garrett Nash, MD, MPH, an attending surgeon on colorectal service at Memorial Sloan Kettering Cancer Center, told Health.
However, experts stress that appendix cancer is still exceedingly rare, so the risk of developing this disease is low.
Cancer can grow from cells that make up the appendix, a small pouch of tissue in the abdomen that’s part of the intestines and colon. Doctors aren’t entirely sure what the appendix does, but they think it may support immune function.
There are two types of appendix cancer:
- Neuroendocrine appendiceal cancer: The most common type, this kind of cancer grows from enterochromaffin cells, which produce chemicals that help digestion and movement in the gut.
- Epithelial appendiceal cancer: This type occurs in cells that line the appendix.
The most common presentation of early-stage appendix cancer is appendicitis, when the appendix becomes inflamed and infected. Most cases of appendix cancer remain undiagnosed until after someone has the organ removed due to appendicitis.
“Cure rates are very high when the cancer is confined to the appendix,” Nash said. But if the appendix bursts, any tumor cells can spread throughout the abdominal cavity, added Andreana Holowatyj, PhD, an assistant professor of hematology and oncology at the Vanderbilt University Medical Center who led the research team.
To assess incidence rates among age groups, the research team pulled data from the National Cancer Institute about 4,858 people aged 20 or older who were diagnosed with appendix cancer between 1975 and 2019.
After grouping people by birth year, the scientists discovered that, compared to people born in the 1940s, appendix cancer rates more than tripled among Generation Xers born in the 1970s and early 1980s and quadrupled among older millennials born between 1981 and 1990.
The finding comes as an increasing number of younger adults are being diagnosed with other cancers, including those of the colon, breast, uterine, prostate, and stomach.
In fact, rising cases of colon cancer in younger generations is what inspired Holowatyj to want to study appendix cancer. Her previous research showed that one in three people with the disease are diagnosed before they reach the age of 50.
In the U.S., appendix cancer has been thought to affect only about one or two people per one million a year, according to the National Cancer Institute. While the organization does note that “recent studies show that appendiceal cancer is becoming more common,” Michael Foote, MD, an oncologist at Memorial Sloan Kettering Cancer Center, said that it still “remains extremely rare.”
“So saying that it’s surging,” he continued, “could mean just a few more people are diagnosed each year.”
A 2023 report noted that a variety of factors, such as diet, lifestyle, and exposure to environmental toxins and antibiotics, could be driving a surge in gastrointestinal cancer cases among younger adults.
As for the rise of appendix cancer specifically, Holowatyj noted that the cause remains unknown, but she believes it’s likely “a constellation of factors—and the intersection of those factors overall.”
Nash, meanwhile, identified environmental exposures as “the leading suspect.”
Because cases of appendix cancer are rising but appendectomy procedures aren’t, the increase in cancer cases likely isn’t because of more detections, Holowatyj pointed out.
In a study involving 352 people with appendix cancer that Holowatyj worked on but has not yet been published, younger people showed symptoms more often than older adults.
The most prevalent symptoms were:
- Abdominal pain
- Bloating/distension
- Pelvic pain
- Having an abdominal or pelvic mass
Other symptoms can include fluid build-up, increasing waist size, diarrhea, nausea, and vomiting.
However, most symptoms don’t often show up until the cancer is at a later stage, according to theMD Anderson Cancer Center. “Unfortunately, the majority [of appendix cancer cases] present as stage IV,” Nash said.
With symptoms not always obvious, no preventive screening method, and diagnosis largely only after appendix removal, Holowatyj said it’s important to be aware of any symptoms and alert your doctor.
If you had appendicitis but didn’t have it removed, schedule a follow-up scan to minimize the risk that the appendicitis masked a tumor, Nash advised.
“I think the biggest take home [message] is…‘See something, say something,’” Holowatyj said.
