Article Impact Level: HIGH Data Quality: STRONG Summary of Annals of Internal Medicine, ANNALS-24-02479. https://doi.org/10.7326/ANNALS-24-02479 Dr. Andreana N. Holowatyj et al.
Points
- A SEER-based study of 4,858 cases found that appendiceal adenocarcinoma incidence has sharply increased in recent U.S. birth cohorts, with the 1985 cohort showing a fourfold rise compared to 1945.
- This rising trend was consistent across all histologic subtypes of appendiceal adenocarcinoma, with the most significant increases seen in Generation X and Millennial birth cohorts.
- The findings suggest a growing disease burden in younger generations, emphasizing the need for increased clinical vigilance and awareness among healthcare professionals and the public.
- Despite limitations such as the low number of signet ring cell carcinoma cases, the study’s results mirror similar increases in other gastrointestinal cancers across successive generations.
- Researchers advocate for focused etiologic studies and improved strategies for early detection to address the rising incidence and potential future impact of appendiceal adenocarcinoma.
Summary
A retrospective cohort study utilizing the SEER (Surveillance, Epidemiology, and End Results) database assessed the incidence rates of appendiceal adenocarcinoma (AA) across different birth cohorts in the United States from 1975 to 2019. The study included 4,858 individuals aged 20 years or older who were diagnosed with pathologically confirmed AA. The researchers created 21 overlapping birth cohorts from 1891–1899 to 1991–1999 and estimated the age-specific incidence rates for AA relative to the 1945 birth cohort. They found that the incidence of AA has significantly increased in recent birth cohorts, with the 1980 cohort experiencing a tripling of incidence (incidence rate ratio [IRR], 3.41 [95% CI, 2.54 to 4.56]). The 1985 cohort showed a quadrupling of incidence (IRR, 4.62 [95% CI, 3.12 to 6.82]) compared with the 1945 cohort.
This increase in AA incidence was seen across all histologic subtypes, including nonmucinous, mucinous, goblet cell, and signet ring cell carcinoma. The magnitude of the increase varied, but it was particularly notable among individuals born after 1945, especially in Generation X and Millennials. The findings suggest that the rising incidence of AA in younger generations may indicate a future increase in the disease burden. Given the rarity of AA and its growing incidence, the study calls for targeted etiologic research and heightened awareness of AA among healthcare providers and the public.
While the study identified clear trends in the rising incidence of AA, it also highlighted some limitations, including the inability to examine signet ring cell carcinomas in detail due to the rarity of this subtype. The study’s results align with similar trends observed in other gastrointestinal cancers, suggesting shared environmental or genetic factors contribute to the increasing incidence of cancers like AA across generations. The authors emphasize the importance of further research to understand better the factors driving these trends and improve early detection and prevention.
Link to the article: https://www.acpjournals.org/doi/10.7326/ANNALS-24-02479
References Holowatyj, A. N., Washington, M. K., Goldberg, R. M., & Murphy, C. C. (2025). Birth cohort effects in appendiceal adenocarcinoma incidence across the united states. Annals of Internal Medicine, ANNALS-24-02479. https://doi.org/10.7326/ANNALS-24-02479
