How Does Military Service Impact Cancer Risk? It’s Complicated

CHICAGO—While it’s extremely difficult to link cancer rates to military service, researchers are starting to get some initial inklings of possible connections, a US Department of Veterans Affairs (VA) oncologist told an audience at the 2023 annual meeting of the Association of VA Hematology/Oncology.

One study found surprising levels of abnormal proteins and cancer in the blood of service members, said Christin DeStefano, MD, of David Grant US Air Force Medical Center at Travis Air Force Base in California. Another may have uncovered a link between military trauma and lymphoma. And an analysis of pilots found they have higher rates of certain kinds of cancer— but lower levels of other cancer types.

“It is hard to tell if service-related exposures heighten the risk of cancer. Some aspects of military service might increase cancer risk,” DeStefano said. “But other aspects of military service might decrease cancer risk.”

The VA has been especially focused on the possible link between military service and cancer since the passage of the PACT Act in 2022. The legislation prioritizes claims for cancer, terminal illnesses, and homelessness, and it’s sparked more than 4.1 million free toxic-exposure screenings for veterans.

VA Under Secretary for Health Shereef Elnahal, MD, MBA, noted in the keynote address at the 2023 AVAHO annual meeting that “Every type of solid tumor is now considered a presumptive condition associated with burden of exposure to veterans deployed anywhere in Central Command, either in the Persian Gulf War or the post-9/11 conflicts.”

DeStefano noted that there are a variety of challenges to analyzing data regarding connections between military exposure and cancer. For one, “it’s hard to include people from the time they enter the military to postmilitary service. Some are getting their health care in the civilian health care systems.” In addition, “There are a lot of problems with ICD-9 and ICD-10 codes, which can be very erroneous. Maybe somebody came in with a mass, the doctor or the nurse practitioner was busy and they put down ‘suspected cancer,’ and now they have that ICD code in their chart where they never actually had cancer.” This is why more reliable cancer registries are so important, she said.

Another challenge is figuring out when exposures occurred and whether they actually occurred in the military at all. “There are multiple studies suggesting that a first driver event is often acquired 20 to 40 years before a cancer diagnosis, often in one’s 20s and 30s,” she said. “It's hard to quantify an exposure, since there can be exposures before military service and exposures after military service. The amount of exposure and duration of exposure might differ, and individuals might metabolize the exposures differently from each other.”

To make matters more complicated, research is pointing in surprising directions. DeStefano highlighted her not-yet-published study of monoclonal gammopathy (MG), a condition in which abnormal proteins are found in the blood, in 534 service members. MG can be a cancer precursor. Those exposed to burn pits in Iraq had similar risks of MG (6.7%) vs an unexposed, matched control group (5.4%; P = .22), Dr. DeStefano said. Over a mean follow-up of 14 years and 10 years, respectively, 7% of participants in each group developed cancer.

“You might think, ‘this is a negative study. There's no difference.’ However, it is very notable that the prevalence of monoclonal gammopathy was 6.1%. That is 3 times as high as we would expect in somebody in their 40s,” she said. “Also, 7% having a cancer diagnosis is not insignificant.” She added: “It is very possible that many of these service members already have full-blown multiple myeloma or something associated with monoclonal gammopathy that just has not been diagnosed yet.”

In another study, this one published in 2021, Dr. DeStefano and colleagues tracked 8834 injured Iraq/Afghanistan veterans and compared them with matched controls to see if there was a link between severe trauma and cancer. There wasn’t  except for lymphoma (22 vs 7 cases, respectively; odds ratio = 3.1; 95% CI, 1.34-7.37; P = .008). The connection remained after adjustment for confounders.

What’s going on? “It’s possible that blast injury might induce some alterations to the immune system that might set the stage for lymphoma genesis,” she said. “Or maybe that blast injury is a surrogate for a toxic exposure: Maybe carcinogens are released during a blast injury.”

Dr. DeStefano also highlighted a 2022 study that tracked 386,190 Air Force officers. The study found that combat pilots (9.1% of the total) had greater adjusted odds of testicular and prostate cancers and melanoma than the other officers. Why? “Military pilots have exposure to cosmic ionizing radiation as well as ultraviolet radiation,” she said.

But while “these are scary, sobering things,” she noted that combat pilots were less likely to develop several cancers than the general population, including kidney, testicular, colorectal, bladder and thyroid cancer, and they were less likely to die from colorectal cancer.

CHICAGO—While it’s extremely difficult to link cancer rates to military service, researchers are starting to get some initial inklings of possible connections, a US Department of Veterans Affairs (VA) oncologist told an audience at the 2023 annual meeting of the Association of VA Hematology/Oncology.

One study found surprising levels of abnormal proteins and cancer in the blood of service members, said Christin DeStefano, MD, of David Grant US Air Force Medical Center at Travis Air Force Base in California. Another may have uncovered a link between military trauma and lymphoma. And an analysis of pilots found they have higher rates of certain kinds of cancer— but lower levels of other cancer types.

“It is hard to tell if service-related exposures heighten the risk of cancer. Some aspects of military service might increase cancer risk,” DeStefano said. “But other aspects of military service might decrease cancer risk.”

The VA has been especially focused on the possible link between military service and cancer since the passage of the PACT Act in 2022. The legislation prioritizes claims for cancer, terminal illnesses, and homelessness, and it’s sparked more than 4.1 million free toxic-exposure screenings for veterans.

VA Under Secretary for Health Shereef Elnahal, MD, MBA, noted in the keynote address at the 2023 AVAHO annual meeting that “Every type of solid tumor is now considered a presumptive condition associated with burden of exposure to veterans deployed anywhere in Central Command, either in the Persian Gulf War or the post-9/11 conflicts.”

DeStefano noted that there are a variety of challenges to analyzing data regarding connections between military exposure and cancer. For one, “it’s hard to include people from the time they enter the military to postmilitary service. Some are getting their health care in the civilian health care systems.” In addition, “There are a lot of problems with ICD-9 and ICD-10 codes, which can be very erroneous. Maybe somebody came in with a mass, the doctor or the nurse practitioner was busy and they put down ‘suspected cancer,’ and now they have that ICD code in their chart where they never actually had cancer.” This is why more reliable cancer registries are so important, she said.

Another challenge is figuring out when exposures occurred and whether they actually occurred in the military at all. “There are multiple studies suggesting that a first driver event is often acquired 20 to 40 years before a cancer diagnosis, often in one’s 20s and 30s,” she said. “It's hard to quantify an exposure, since there can be exposures before military service and exposures after military service. The amount of exposure and duration of exposure might differ, and individuals might metabolize the exposures differently from each other.”

To make matters more complicated, research is pointing in surprising directions. DeStefano highlighted her not-yet-published study of monoclonal gammopathy (MG), a condition in which abnormal proteins are found in the blood, in 534 service members. MG can be a cancer precursor. Those exposed to burn pits in Iraq had similar risks of MG (6.7%) vs an unexposed, matched control group (5.4%; P = .22), Dr. DeStefano said. Over a mean follow-up of 14 years and 10 years, respectively, 7% of participants in each group developed cancer.

“You might think, ‘this is a negative study. There's no difference.’ However, it is very notable that the prevalence of monoclonal gammopathy was 6.1%. That is 3 times as high as we would expect in somebody in their 40s,” she said. “Also, 7% having a cancer diagnosis is not insignificant.” She added: “It is very possible that many of these service members already have full-blown multiple myeloma or something associated with monoclonal gammopathy that just has not been diagnosed yet.”

In another study, this one published in 2021, Dr. DeStefano and colleagues tracked 8834 injured Iraq/Afghanistan veterans and compared them with matched controls to see if there was a link between severe trauma and cancer. There wasn’t  except for lymphoma (22 vs 7 cases, respectively; odds ratio = 3.1; 95% CI, 1.34-7.37; P = .008). The connection remained after adjustment for confounders.

What’s going on? “It’s possible that blast injury might induce some alterations to the immune system that might set the stage for lymphoma genesis,” she said. “Or maybe that blast injury is a surrogate for a toxic exposure: Maybe carcinogens are released during a blast injury.”

Dr. DeStefano also highlighted a 2022 study that tracked 386,190 Air Force officers. The study found that combat pilots (9.1% of the total) had greater adjusted odds of testicular and prostate cancers and melanoma than the other officers. Why? “Military pilots have exposure to cosmic ionizing radiation as well as ultraviolet radiation,” she said.

But while “these are scary, sobering things,” she noted that combat pilots were less likely to develop several cancers than the general population, including kidney, testicular, colorectal, bladder and thyroid cancer, and they were less likely to die from colorectal cancer.

CHICAGO—While it’s extremely difficult to link cancer rates to military service, researchers are starting to get some initial inklings of possible connections, a US Department of Veterans Affairs (VA) oncologist told an audience at the 2023 annual meeting of the Association of VA Hematology/Oncology.

One study found surprising levels of abnormal proteins and cancer in the blood of service members, said Christin DeStefano, MD, of David Grant US Air Force Medical Center at Travis Air Force Base in California. Another may have uncovered a link between military trauma and lymphoma. And an analysis of pilots found they have higher rates of certain kinds of cancer— but lower levels of other cancer types.

“It is hard to tell if service-related exposures heighten the risk of cancer. Some aspects of military service might increase cancer risk,” DeStefano said. “But other aspects of military service might decrease cancer risk.”

The VA has been especially focused on the possible link between military service and cancer since the passage of the PACT Act in 2022. The legislation prioritizes claims for cancer, terminal illnesses, and homelessness, and it’s sparked more than 4.1 million free toxic-exposure screenings for veterans.

VA Under Secretary for Health Shereef Elnahal, MD, MBA, noted in the keynote address at the 2023 AVAHO annual meeting that “Every type of solid tumor is now considered a presumptive condition associated with burden of exposure to veterans deployed anywhere in Central Command, either in the Persian Gulf War or the post-9/11 conflicts.”

DeStefano noted that there are a variety of challenges to analyzing data regarding connections between military exposure and cancer. For one, “it’s hard to include people from the time they enter the military to postmilitary service. Some are getting their health care in the civilian health care systems.” In addition, “There are a lot of problems with ICD-9 and ICD-10 codes, which can be very erroneous. Maybe somebody came in with a mass, the doctor or the nurse practitioner was busy and they put down ‘suspected cancer,’ and now they have that ICD code in their chart where they never actually had cancer.” This is why more reliable cancer registries are so important, she said.

Another challenge is figuring out when exposures occurred and whether they actually occurred in the military at all. “There are multiple studies suggesting that a first driver event is often acquired 20 to 40 years before a cancer diagnosis, often in one’s 20s and 30s,” she said. “It's hard to quantify an exposure, since there can be exposures before military service and exposures after military service. The amount of exposure and duration of exposure might differ, and individuals might metabolize the exposures differently from each other.”

To make matters more complicated, research is pointing in surprising directions. DeStefano highlighted her not-yet-published study of monoclonal gammopathy (MG), a condition in which abnormal proteins are found in the blood, in 534 service members. MG can be a cancer precursor. Those exposed to burn pits in Iraq had similar risks of MG (6.7%) vs an unexposed, matched control group (5.4%; P = .22), Dr. DeStefano said. Over a mean follow-up of 14 years and 10 years, respectively, 7% of participants in each group developed cancer.

“You might think, ‘this is a negative study. There's no difference.’ However, it is very notable that the prevalence of monoclonal gammopathy was 6.1%. That is 3 times as high as we would expect in somebody in their 40s,” she said. “Also, 7% having a cancer diagnosis is not insignificant.” She added: “It is very possible that many of these service members already have full-blown multiple myeloma or something associated with monoclonal gammopathy that just has not been diagnosed yet.”

In another study, this one published in 2021, Dr. DeStefano and colleagues tracked 8834 injured Iraq/Afghanistan veterans and compared them with matched controls to see if there was a link between severe trauma and cancer. There wasn’t  except for lymphoma (22 vs 7 cases, respectively; odds ratio = 3.1; 95% CI, 1.34-7.37; P = .008). The connection remained after adjustment for confounders.

What’s going on? “It’s possible that blast injury might induce some alterations to the immune system that might set the stage for lymphoma genesis,” she said. “Or maybe that blast injury is a surrogate for a toxic exposure: Maybe carcinogens are released during a blast injury.”

Dr. DeStefano also highlighted a 2022 study that tracked 386,190 Air Force officers. The study found that combat pilots (9.1% of the total) had greater adjusted odds of testicular and prostate cancers and melanoma than the other officers. Why? “Military pilots have exposure to cosmic ionizing radiation as well as ultraviolet radiation,” she said.

But while “these are scary, sobering things,” she noted that combat pilots were less likely to develop several cancers than the general population, including kidney, testicular, colorectal, bladder and thyroid cancer, and they were less likely to die from colorectal cancer.