NEW YORK (Reuters Health) – A study of Vietnam War era veterans shows that exposure to Agent Orange is associated with a significantly increased risk of prostate cancer, earlier disease onset and with more aggressive features.

“Consideration should be made to classify this group of individuals as ‘high risk’, just like men of African-American heritage and men with a family history of prostate cancer,” Dr. Karim Chamie, from the University of California Davis, Sacramento, and colleagues conclude.

As reported in the November 1st issue of Cancer, prior research has established a link between Agent Orange exposure and the development of various soft tissue malignancies. The apparent association with prostate cancer, however, was relatively weak, but this may have been because the studies were conducted nearly a decade ago at a point when many of the veterans had not reached an age when prostate cancer is common.

The current investigation, by contrast, involved men who were entering their 60s and, therefore, had an inherently higher risk of prostate cancer. The study included 6214 veterans who were exposed to Agent Orange from 1962 to 1971 and 6930 veterans who were not exposed to the defoliant. The subjects were followed from 1998 to 2006.

Among the exposed group, 239 men were identified with prostate cancer, compared with 124 cases among the unexposed men, for an odds ratio of 2.19. On average, prostate cancer developed 407 months after Agent Orange exposure, the report indicates.

Agent Orange exposure was associated with a younger age at prostate cancer diagnosis (59.7 vs. 62.2 years), a higher prevalence of Gleason scores 8 to 10 (21.8% vs. 10.5%), and higher rate of metastatic disease at presentation (13.4% vs. 4%).

On multivariate analysis, Agent Orange exposure was found to be the strongest predictor of both developing prostate cancer and of high-grade and metastatic disease on presentation, the authors note.

“The current findings support aggressively screening these veterans for prostate cancer in the hopes of detecting high-risk cancers before metastases develop,” the authors state. “The expansion of benefits and screening programs will place further pressures on the VA healthcare system given the current level of budgetary appropriations.”

Reference:
Cancer 2008;113:2464-2470.