A rare but deadly form of cancer is increasing rapidly among younger Americans, according to a new peer-reviewed study.
Researchers at Vanderbilt University Medical Center found that appendix cancer cases have tripled among Generation X and quadrupled among millennials compared to earlier generations.
The findings, published in the Annals of Internal Medicine, reveal that younger adults—those born between 1976 and 1989—are facing unusually high rates of a disease once considered extremely rare. “One in every three appendix cancers is now diagnosed in adults under age 50,” said Dr. Andreana Holowatyj, the study’s lead author. “By contrast, only one in eight colorectal cancers are diagnosed in the same age group.”
Appendix cancer affects about 1 to 2 people per million annually in the U.S., according to the National Cancer Institute. But despite its rarity, the researchers warn the upward trend points to a broader public health concern.
Holowatyj and her team analyzed records from the National Cancer Institute’s SEER program, which tracks long-term cancer trends. Between 1975 and 2019, they found 4,858 confirmed cases—many in people ages 18 to 49. The SEER database, which covers nearly half the U.S. population, is one of the most reliable sources for analyzing disease trends.
Medical experts are now asking whether appendix cancer is part of a larger increase in gastrointestinal (GI) cancers affecting younger adults. “We’ve been observing the same pattern in colorectal and stomach cancers,” said Dr. Andrea Cercek of Memorial Sloan Kettering Cancer Center. She and others suspect environmental factors such as food and water contamination, microplastics, lifestyle changes, and dietary habits may be to blame.
Another challenge is that appendix cancer is difficult to detect early. Most people show no symptoms in its early stages, and 95% of cases are only discovered after surgery for appendicitis. “It’s not easy to detect or screen for appendix cancer,” said Dr. Deborah Doroshow, a cancer specialist at Mount Sinai. “It doesn’t usually show up on abdominal scans or during colonoscopies.” That often results in a diagnosis only after the cancer has spread, leading to worse outcomes.
Typical symptoms, if they appear, may include abdominal pain, bloating, nausea, vomiting, or a sudden feeling of fullness while eating. Still, these are often mistaken for minor digestive issues. “Young patients are sometimes dismissed because of their age,” Doroshow warned. “Especially women and people of color may face more difficulty getting timely diagnoses.”
The five-year survival rate for appendix cancer ranges widely—from 10% to 63%—depending on how early it’s caught and what type it is. Treatments usually include surgical removal of the appendix and affected tissue, followed by chemotherapy if the disease has spread.
Researchers are urging more study into both environmental and genetic causes of the disease. For now, the best tools available are public awareness and clinical vigilance. “The rise in appendix cancer is a signal we can’t ignore,” Holowatyj said. “The sooner we understand what’s behind it, the better we can protect future generations.”