(UroToday.com) The 2024 South Central AUA annual meeting included a session on bladder cancer, featuring a presentation by Dr. Gal Saffati discussing exposures and bladder cancer risk among military veterans. Bladder cancer is a significant concern among veterans, with approximately 3,200 U.S. veterans diagnosed annually, making it the fourth most diagnosed cancer within the Veterans Affairs (VA) system.
While established risk factors such as smoking, age, gender, and exposure to carcinogens are known, a notable portion of cases arise without identifiable risk factors. Military personnel are a unique population who may have encountered higher levels and varieties of carcinogenic agents during their service than the general population. Recent attention has been drawn to herbicides like Agent Orange (2,3,7,8-tetrachlorodibenzo-p-dioxin), Agent Blue (arsenical cacodylic acid), and depleted uranium, all of which have been implicated in bladder cancer incidence among veterans, although further research is needed to fully understand these associations. Dr. Saffati and colleagues conducted a systematic review and meta-analysis to evaluate the existing literature regarding exposure to potential carcinogens and the occurrence of bladder cancer among veterans.
In December 2023, a systematic review was performed following the PRISMA guidelines. PubMed, Scopus, and Ovid MEDLINE were queried for terms related to bladder cancer incidence, as well as terms associated with veterans. Studies included retrospective cohort studies, reviews, and observational studies. These search terms were paired with potential carcinogens identified via preliminary topic exploration. Data was extracted independently by two authors and analyzed.
A total of 26 studies involving 4,320,262 patients were included. Seven of these studies examined the impact of Agent Orange, with 1,017,100 exposed patients and 2,467,819 control patients. Among them, four studies reported hazard ratios, encompassing a total of 2,705,283 veterans. The meta-analysis demonstrated a notable rise in bladder cancer risk among Agent Orange-exposed individuals (HR 1.17, 95% CI 1.01-1.36, p < 0.00001):
Additionally, four studies investigated hazard ratios for bladder cancer incidence with depleted uranium exposure (28,485 exposed patients). The meta-analysis revealed a significant increase in bladder cancer risk among depleted uranium-exposed patients (HR 2.13, 95% CI 1.31-3.48, p = 0.002):
Other exposures were contaminated drinking water, ionizing radiation, chromates, diesel fumes, cutting oils, asbestos, and solder. Meta-analyses were not conducted for these exposures, as no single exposure possessed the available aggregate data to synthesize a cumulative hazard ratio.
Dr. Saffati concluded his presentation discussing exposures and bladder cancer risk among military veterans with the following take-home points:
- This review confirms an association between Agent Orange and depleted uranium military exposures and heightened bladder cancer risk among veterans
- These findings emphasize the urgent need for early screening, enhanced clinical management strategies, and preventive measures for veterans exposed to these carcinogenic agents
- Moving forward, future research needs to focus on elucidating the specific carcinogenic agents driving these findings and further illustrating the disproportionate prevalence of identified exposures among veterans
Presented by: Gal Saffati, Research Fellow, Baylor College of Medicine, Houston, TX
Written by: Zachary Klaassen, MD, MSc – Urologic Oncologist, Associate Professor of Urology, Georgia Cancer Center, Wellstar MCG Health, @zklaassen_md on Twitter during the 2024 South Central American Urological Association (AUA) Annual Meeting, Colorado Springs, CO, Wed, Oct 30 – Sat, Nov 2, 2024.