Thursday, July 22, 2010

AIR FORCE TIMES: Troops have higher rates of some cancers, says study


Written by Kelly Kennedy - Staff writer, military Times group

(Air Force Times) -  After looking at 10 years’ worth of cancer data, researchers at the Armed Forces Health Surveillance Center found that service members tend to have higher rates of melanoma, brain, non-Hodgkin lymphoma, breast, prostate and testicular cancers than civilians.

They also found interesting differences across the services. Airmen are more likely to suffer skin cancer than other service members, for example, while sailors are the most likely to have lung cancer. Coast Guardsmen have the highest rates of testicular cancer, while Marines tend to the have the lowest cancer rates overall.

Military researchers say the rates have remained stable — though the incidence rate of these particular kinds of cancer has increased from 51 per 100,000 troops in 2000, to 57.5 per 100,000 in 2006, and then back down to 54.5 per 100,000 in 2009.

“There were no clear trends of increasing or decreasing incidence of specific [cancer] sites or overall” cancer rates, the report states. “In general, the strongest demographic correlate of increased risk of a cancer was older age.”

That held true for all cancers except for cervical and testicular, the report states.

To conduct the study, researchers looked at how many times a service member had been seen for a diagnosis, whether a member had been treated with radiotherapy or chemotherapy, or whether a member’s medical code showed he had been diagnosed with a cancer. They found the lowest number of diagnoses from cancer over the past decade was in 2000, with 710. The highest rate came in 2006 with 802. There were 7,579 total diagnoses over the 10 years.

During those years, 904 service members died of cancer. The fewest deaths came in 2000 with 44; the most deaths came in 2005 with 125. Of those who died, 106 died of lung cancer, 101 died from brain or other nervous system cancers, and 92 died of colon cancer.

Researchers expected to see more cases related to tobacco smoking because 31 percent of service members smoke, compared to 20 percent of civilians. However, “lung cancer cases related to current tobacco smoking may not be clinically apparent until affected members leave active service,” researchers said.

The highest rates were for breast cancer. Service women ages 20 to 24 were diagnosed with breast cancer at a rate of 2.5 per 100,000, compared to civilians who were diagnosed at a rate of 1.5 per 100,000. Those numbers greatly increased for service women as they aged. Military women ages 35 to 39 were diagnosed at a rate of 77.3 per 100,000, compared to civilians who were diagnosed at a rate of 59.3 per 100,000.

Researchers explained that military personnel are younger and healthier than civilians, so one might think that the rates overall would be lower. However, the researchers reasoned, service members have unlimited access to health care, as well as required annual exams, so they may be diagnosed more frequently and at younger ages than civilians.

But that doesn’t completely explain disparities among the services, such as why Marines — who have access to the same health care as members of other branches — have significantly lower rates of these cancers than either their military peers or civilians.

For example, the Air Force rate for malignant melanoma was 14.8 per 100,000, while the rate for Marines was 6.5 per 100,000. And sailors had almost double the rate of lung cancer as people from other services.

This was the first report to look cancer rates in all services. Another recent study conducted by K. Zhu at the U.S. Military Cancer Institute at Walter Reed Army Medical Center compared data from the Defense Department’s Automated Central Tumor Registry and from the National Cancer Institute from 1990 to 2005.

Zhu found that colorectal cancer in white troops, lung cancer in white and black male troops and white female troops, and cervical cancer in black female troops were significantly lower than similar civilian populations.

However, breast cancer and prostate cancer rates were significantly higher in both black and white troops than in civilians. Prostate cancer rates were also higher in military patients.

“Overall, these results suggest that cancer patterns may differ between military and nonmilitary populations,” Zhu wrote.

A second study of Air Force personnel, by G. Yamane, found that invasive cancers had “decreased significantly” from 1989 to 2002. Cancer rates for female airmen were about the same as civilian populations, and Air Force men had lower cancer rates. However, cervical, prostate and vulvar cancers were “significantly higher.”

And a third study, published in the Medical Surveillance Monthly Report in 2008, found that service members had lower rates of colorectal, lung and cervical cancers, and higher rates of prostate and breast cancers.

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