Study Finds Appendix Cancer Rates Have Quadrupled Among Millennials

Cases of appendiceal cancer tripled for Americans born between 1976 to 1984 and quadrupled for those born between 1981 to 1989, according to a study published June 9 in the Annals of Internal Medicine.

The study compared chronological data in five-year intervals from the National Cancer Institute’s Surveillance, Epidemiology and End Results (SEER) Program, using 1941 to 1949 as the baseline. The lead author, Andreana Holowatyj, PhD, MSCI, assistant professor of Medicine at Vanderbilt University Medical Center and Vanderbilt-Ingram Cancer Center, said the findings reveal the need for increased awareness about appendiceal cancer from both clinicians and the public as well as more research to determine the reasons for the sharp spike in incidence.

“When you take these alarming rates that we are seeing for appendiceal cancer across generations, together with the fact that 1 in every 3 patients diagnosed with appendiceal cancer is diagnosed under the age of 50, these point to a timely need for everyone to be aware of the signs and symptoms of appendix cancer.

“Albeit cancer of the appendix is rare, it is important for individuals who have these symptoms to see a health care professional. Ruling out the possibility of an appendix cancer diagnosis, or diagnosing it early, is important for this cancer as we continue to learn what factors may be contributing to this worrisome trend,” Holowatyj said.

Symptoms may include abdominal pain, bloating, changes in bowel habits, and loss of appetite.

Appendiceal cancer is a rare cancer with about 3,000 new cases diagnosed every year in the United States, according to prior studies, but Holowatyj and colleagues took a closer look at statistics by combing through the SEER database.

“As incidence rates in younger generations are often indicative of future disease burden, these results support the need for histology-specific investigations of appendiceal adenocarcinoma, as well as increased education and awareness of appendiceal adenocarcinomas among health care providers and the public,” the study stated.

Appendiceal cancer has had no standardized screening guidelines, risk factors or tumor classifications — a lack of clinical evidence that has resulted in late diagnosis and poor prognosis. Up to 1 of every 2 patients is diagnosed with distant metastatic disease, and five-year survival rates vary between 10% and 63%.

Earlier this year, Holowatyj and a team of experts identified six key research priority areas to deliver a fundamental understanding of appendiceal tumors and to improve treatments and outcomes for patients.

The recommendations published Feb. 20 in Nature Reviews Cancer are the result of a concerted focus by the Appendix Cancer Pseudomyxoma Peritonei (ACPMP) Research Foundation to better understand the disease that afflicts an estimated 3,000 new patients across all age groups each year.

The recommendations arose from the inaugural ACPMP Research Foundation Scientific Think Tank, sponsored by ACPMP and chaired by Holowatyj at Vanderbilt-Ingram Cancer Center in December 2023.

The current study in the Annals of Internal Medicine received support from the Appendix Cancer PMP Research Foundation and the National Institutes of Health (grants K12HD043483 and P50CA236733).

Other authors on the study are Mary Kay Washington, MD, PhD, professor of Pathology, Microbiology and Immunology at VUMC, Richard Goldberg, MD, of the West Virginia University School of Medicine, and Caitlin Murphy, PhD, MPH, of the UT Health Houston School of Public Health.