In the FY2021 NDAA Sec. 750 requirement, a two-phase study strategy was mandated. Phase 1 requires an epidemiologic study to determine if there is a higher rate of cancers and cancer mortality occurring for military aircrew and ground crew as compared to the U.S. population using the Surveillance, Epidemiology, and End Results database. The Phase 1 study was performed by the Defense Health Agency’s Armed Forces Health Surveillance Division, in collaboration with the National Cancer Institute, North American Association of Central Cancer Registries, the Military Departments, and the Murtha Cancer Center at Walter Reed National Military Medical Center.

There were 156,050 aircrew and 737,891 ground crew included and followed in the study between 1992 and 2017. Military members from all services were included.

The study was conducted between July 2021 and April 2022.

The Phase 2 study is required to investigate and identify the specific occupational and environmental risk factors associated with the increased risk of the cancers identified in the Phase 1 study.

Compared to the U.S. population, aircrew had a:

• 87% higher rate of melanoma,
• 39% higher rate of thyroid cancer,
• 16% higher rate of prostate cancer, and a
• 24% higher rate of cancer for all sites combined.

Ground crew members had higher rates of:

• Cancers of brain and nervous system (by 19%),
• Thyroid cancer (by 15%),
• Melanoma (by 9%),
• Kidney and renal pelvis cancer (by 9%), and
• Cancer of all sites combined (by 3%).

Rates of other site-specific cancers were either similar to or less than the U.S. population.

The FY2021 NDAA Sec. 750 requires a Phase 2 study, since the Phase 1-a study found there's an increased rate of cancers or cancer mortality among military aircrew or ground crew.

The current data isn't sufficient to determine a link between military occupations and cancer. The Phase 1-a study showed higher rates of cancer diagnoses in military aviators and ground support personnel than in the U.S. population when matched for age, race, and sex. However, these findings can't determine whether military occupations and cancers are linked. The purpose of the Phase 2 study will look at military occupational exposures and cancers.

Phase 1-a of the study didn't include these groups. However, by obtaining data from the Department of Veterans Affairs Central Cancer Registry (VACCR) and 46 state cancer registries, Phase 1-b will capture National Guard and Reserve service members.

Yes, the Phase 1-b study includes additional data from the Department of Veterans Affairs Central Cancer Registry (VACCR), which will result in a better understanding of cancer cases for veterans.

Yes, but previous studies have primarily focused on U.S. Air Force aviators. Our study is one of the largest to date and includes aviators from the Army, Navy, Air Force, and Marine Corps.

Although no observational study can demonstrate a causal effect, DOD will engage evidence-based mitigation measures if the weight of evidence is consistent with there being a causal effect of military occupations and cancer rates.

We anticipate delivery of findings of the second part of the Phase 1 study at the end of 2023. This second part of Phase 1 (referred to as Phase 1-b) will examine the rates of cancer diagnoses in Reserve and National Guard aviators and ground crew. The second study will begin shortly after, and an end date has not been set.

A recent study from the Millennium Cohort Study, published in March 2023, found a lower rate of cancer mortality in deployed military members, referred to as the “healthy deployer affect.”