Experts are Baffled by the Increase of a Rare Cancer in Young People

A seldom-seen cancer is increasingly being diagnosed in younger generations, and experts remain uncertain about the cause. Recent studies in the United States indicate that individuals from Generation X and Millennials are three to four times more likely than older adults to develop cancer of the appendix, a small organ attached to the digestive tract that rarely draws attention until issues arise.

Traditionally, appendiceal cancers were largely confined to older adults. Today, however, about one-third of patients with this cancer are under 50. Epidemiologist and molecular biologist Andreana Holowatyj from Vanderbilt University, who has led multiple investigations on the topic, is working to understand this rise. For years, she has monitored the growing incidence across age groups.

While other cancers have seen significant progress in detection and treatment, appendix cancer remains poorly understood, Holowatyj stated in 2024. A prior national study she led revealed a 232% increase in malignant appendix cancer cases in the US from 2000 to 2016, affecting all generations.

Once considered vestigial, the appendix is now understood to have potential roles in gut health. Inflammation, known as appendicitis, is the most common complication, and cancer is occasionally discovered after surgical removal.

Symptoms of appendix cancer, including abdominal pain, bloating, and pelvic discomfort, often mimic more common conditions such as digestive issues or colorectal cancer, which affects approximately 150,000 Americans annually. By contrast, appendix cancer affects roughly 3,000 people each year, resulting in limited research and awareness.

Holowatyj emphasizes the importance of medical evaluation for relevant symptoms: Even though appendiceal cancer is rare, early diagnosis is crucial, and ruling it out should be a priority as we investigate contributing factors to this concerning trend.

Currently, no standard screening protocols exist, and treatment options are limited. The cancer can be difficult to detect, especially as non-surgical management of appendicitis grows more common. It may be mistaken for hernias, fibroids, cysts, or, in women, endometrial lesions. Appendiceal tumors have distinct molecular characteristics compared to colorectal cancers, Holowatyj noted in 2020. They behave differently, respond poorly to typical colorectal chemotherapy, and disproportionately affect younger adults.

Recent findings show a dramatic increase in appendix cancer among those born between 1976 and 1984, with cases tripling, and a quadrupling among those born from 1981 to 1989. The reasons remain unclear. Possible contributors include shifts in diet, activity levels, genetic predispositions, environmental exposures like plastics or chemical contaminants, and even water quality changes.

Surgical oncologist Steven Ahrendt of the University of Colorado, not involved in the studies, noted seeing more young patients with advanced appendix tumors. With colon cancer rising among young adults, its plausible that similar factors affect appendix cancer, he said.

Other research highlights a broader trend: gastrointestinal cancers are rising among people under 50, with significant increases in cancers of the bowel, appendix, bile duct, and pancreas. Diet, poor sleep, ultra-processed foods, alcohol, persistent chemical pollutants, and microplastics are suspected contributors.

Holowatyj and her team continue to explore risk factors and mechanisms behind appendix cancer. Because it is so rare, this cancer has limited attention. We are dedicated to advancing understanding and treatment options for affected patients, she stated. Recent studies were published in Gastroenterology and the Annals of Internal Medicine.

Author: Connor Blake