Veterans More Likely to Develop Breast, Prostate Cancer Than Civilians: Study

The United States active duty military population may differ from the United States general population in its exposure to cancer risk factors and access to medical care.  However, there is limited research regarding whether cancer incidence rates differ between these two populations.  Previous studies have focused on either a specific cancer or a specific branch of the military.  In an effort to gain a broader understanding, a 2009 study compared the incidence rates of six cancers (lung, colorectum, prostate, breast, testicular, and cervical) among all active duty military personnel and the general population.

How Was Data Collected and Analyzed?

In this study, data was analyzed from the Department of Defense’s Automated Central Tumor Registry (ACTUR) and the National Cancer Institute’s Surveillance, Epidemiology, and End Results (SEER) nine cancer registries for the years 1990-2004.  Both populations were restricted to persons aged 20-59 years old.

ACTUR (Military Population)

ACTUR was established in 1986 as the cancer database and clinical tracking system for the Department of Defense (DoD).  Military medical treatment facilities are required to report cancer data on all DoD beneficiaries, including active duty personnel and their family members, retired military personnel, and National Guard and Reserves personnel who are temporarily activated.  The current study analyzed 1990-2004 data, confined to military personnel on active duty.  The following items from ACTUR were used in the data analysis process: primary cancer site, age at diagnosis, gender, and race.

SEER (General Population)

SEER collects and publishes cancer statistics from population-based cancer registries.  For the current study, cancer rates from 1990-2004 were drawn from the SEER-9 Registries Database (Atlanta, Connecticut, Detroit, Hawaii, Iowa, New Mexico, San Francisco-Oakland, Seattle-Puget Sound, and Utah), comprising approximately 10 percent of the U.S. population.  The incidence of the six above-mentioned cancers was analyzed by gender, year of diagnosis, and race.

Results Show Breast, Prostate Cancer More Common Among Military Population

In regards to the six cancers examined, the most common among active duty military personnel were testicular cancer, followed by prostate, breast, and colorectal cancers.  In the SEER population, breast cancer was the most common among women, followed by lung, prostate, and colorectal cancers.  When comparing incidence rates between populations, the study found the following:

• For colorectal cancer, incidence was significantly lower in the ACTUR population compared to the SEER population, except for black women.
• For cervical cancer, incidence was significantly lower in the ACTUR population compared to the SEER population among black men and women, but not among white men and women.
• For lung cancer, incidence was significantly lower in the ACTUR population compared to the SEER population.
• Incidence rates of breast and prostate cancers were significantly higher in the military population across race and gender.
• For testicular cancer, there was no significant difference in incidence rates between populations.

Overall, the study found differences in cancer incidence rates between military personnel and the general population insofar as rates were lower among military personnel for colorectal, lung, and cervical cancers, but higher for breast and prostate cancers.  Specifically, prostate cancer rates in the military were twice those in the general population, and breast cancer rates were 20 – 40 percent higher.  Importantly, the rates of prostate cancer over time increased rapidly among military personnel across racial groups:

• Incidence rates of prostate cancer doubled among the white SEER population, but tripled among the white ACTUR population.
• Incidence rates of prostate cancer more than doubled among the black SEER population, but increased more than eight-fold among the black ACTUR population.

What Factors Contribute to the Different Incidence Rates Between Populations?

Variations in some risk factors may have contributed to the higher incidence rates of breast cancers in the military population.

Breast Cancer

With respect to breast cancer, military women may differ from those in the general population in reproductive history, such as age at first birth and the use of contraceptives.  Research shows that women in the military are more likely to use oral contraceptive pills, which have been demonstrated to increase the risk of breast cancer, particularly in younger women.  Additionally, women in the military are more likely to be engaged in industrial jobs than females in the general population.  In doing so, they are more likely to be exposed to chemicals that may be related to breast cancer.

Prostate Cancer

While research findings are inconsistent, depleted uranium has been suggested to increase the risk of prostate cancer.  Military personnel are more likely to be exposed to depleted uranium, which could have contributed to the increased risk of prostate cancer and incidence rates.

In both cases, differences may also be related to free access to medical care for the military population.  Military members may have more frequent visits to the doctor and thus are more likely to undergo breast and prostate cancer screenings.  Several studies have confirmed that cancer screening is associated with increases in breast and prostate cancer incidence rates.

Conclusions

Ultimately, findings of similarities and differences in incidence rates between military personnel and the general population according to cancer, race, and gender over time suggest that further research on risk factors and cancer screening practices in the military are warranted.  Such research may lead to a better understanding of etiology and the development of preventative strategies for both populations.