Younger Generations Increasingly Affected by Appendix Cancer

Rising Incidence

Appendiceal adenocarcinoma (AA) remains a rare disease even among medical professionals (in the U.S., only 1 to 2 cases per million people are diagnosed annually). However, its incidence has been increasing in recent years.

A 2021 study showed that in the United States, one in three AA cases is diagnosed in adults under the age of 50. To investigate the causes, researchers analyzed the occurrence of AA across overlapping five-year birth cohorts.

Younger Generations at Risk

Authors of a recently published study in the Annals of Internal Medicine used data from the Surveillance, Epidemiology, and End Results (SEER) program, which includes information from 8 nationally representative cancer registries covering approximately 45.9% of the U.S. population. From 1975 to 2019, SEER recorded 4,858 AA cases.

Compared to the 1945 birth cohort (born between 1941 and 1949), the incidence of AA more than tripled in those born around 1980, and more than quadrupled in those born around 1985.

This trend suggests the disease is becoming more common in newer generations, underscoring the importance of identifying causes and attempting to reverse this pattern.

Causes Remain Unclear

The risk factors and precise causes of AA are not well understood. Potential contributors include frequent antibiotic use in childhood and in the food industry, shifting lifestyle patterns, the rise in obesity rates since the 1970s, and harmful environmental exposures.

Similar trends are observed in other gastrointestinal malignancies, indicating that there may be shared causes driving the rise in incidence across generations.

Challenging to Detect

AA symptoms develop late and, unlike other gastrointestinal cancers, are difficult to detect through imaging or colonoscopy. Tumors are often discovered incidentally. Around 95% of cases are only identified after an appendectomy performed for suspected appendicitis—raising the risk of late diagnosis and worse outcomes.

What Are the Conclusions?

The presented data highlight the need to study AA etiology and raise awareness among healthcare providers and the public. One such effort is the ongoing Appendiceal Cancer Consortium (APPECC), which aims to identify AA risk factors and their link to prognosis.

Editorial Team, Medscope.pro

Sources:

1. Holowatyj A. N., Washington M. K., Goldberg R. M. et al. Birth Cohort Effects in Appendiceal Adenocarcinoma Incidence Across the United States. Annals of Internal Medicine 2025 Jun 10, doi: 10.7326/ANNALS-24-02479.

2. Appendiceal Cancer. National Cancer Institute. Available at: www.cancer.gov/.../appendiceal-cancer

3. Gibbs T., Washington M. K., Eng C. et al. Histologic and Racial/Ethnic Patterns of Appendiceal Cancer among Young Patients. Cancer Epidemiol Biomarkers Prev 2021 Jun; 30(6): 1149–1155, doi: 10.1158/1055-9965.EPI-20-1505.

4. Study reveals alarming rise in appendix cancer among Millennials and Generation X. The Jerusalem Post. Available at: www.jpost.com/health-and-wellness/article-857155

5. Appendiceal Cancer Consortium (APPECC). National Cancer Institute. Available at: www.epi.grants.cancer.gov/cohort-consortium/projecthub/activeprojects/project-proposal/33