Appendicitis before Age 20 Years Is Associated with an Increased Risk of Later Prostate Cancer

Background: Appendicitis before age 20 years has been observed to influence the risk of several inflammatory conditions, possibly through underlying immunological mechanisms. Inflammation has further been suggested to be involved in prostate cancer development. We therefore hypothesized that immunological characteristics signaled by appendicitis before late adolescence might influence the risk of later prostate cancer, and aimed to evaluate this association in a population-based study.Methods: We identified a large cohort of Swedish men who underwent assessment for military conscription around the age of 18 years (n = 242,573). Medical diagnoses at time of conscription were available through the Swedish Military Conscription Register. The Swedish Cancer Register was used to identify diagnoses of prostate cancer. Multivariable adjusted Cox regression analyses were used to estimate HR and 95% confidence intervals (95% CIs) for the association between appendicitis and prostate cancer.Results: During a median of 36.7 years of follow-up, 1,684 diagnoses of prostate cancer occurred. We found a statistically significant association between appendicitis and overall prostate cancer (adjusted HR 1.70; 95% CI, 1.08-2.67). The risk was notably increased for advanced (HR 4.42; 95% CI, 1.74-11.22) and lethal (HR 8.95; 95% CI, 2.98-26.91) prostate cancer.Conclusions: These results suggest that a diagnosis of appendicitis before adulthood potentially signals underlying immune characteristics and a pattern of inflammatory response relevant to prostate cancer risk.Impact: The study lends support to the proposed role of inflammation in prostate carcinogenesis, and adds another area of investigation potentially relevant to prostate cancer development. Cancer Epidemiol Biomarkers Prev; 27(6); 660-4. ©2018 AACR.