Incidence rates of soft tissue sarcoma among U.S. military servicemen: Comparison with the rates in the general U.S. population

Background: Soft tissue sarcoma (STS) is one of the most frequently diagnosed cancers among men younger than age 30 years and a leading cause of cancer death in men younger than age 40 years. The military may be more exposed to STS risk factors and have generally better health and health care access than the general population, which may relate to lower cancer risk and/or early detection. This study compared STS incidence between servicemen and men in the general U.S. population. Methods: Data were from the Department of Defense’s Automated Central Tumor Registry (ACTUR) and the National Cancer Institute’s Surveillance, Epidemiology, and End Results (SEER) program. Subjects were active-duty servicemen in ACTUR and men in SEER aged 18–59 years diagnosed with STS from 1990 to 2013. Age-adjusted rates, incidence rate ratios (IRR), and 95% CIs were calculated. Results: STS incidence rates were lower in ACTUR than SEER overall (IRR = 0.86 [0.78-0.93]), for 18- to 39-year-old men (IRR = 0.78 [0.70-0.86]), by race (White: IRR = 0.85 [0.77-0.95]; Black: IRR = 0.77 [0.63-0.94]), for sites other than skin/connective/soft tissue (IRR = 0.49 [0.37-0.63]), other specified histologies (IRR = 0.84 [0.71-0.98]), and unspecified histology (IRR = 0.57 [0.38-0.82]). Rates were lower in ACTUR for regional (IRR = 0.37 [0.28-0.47]) and distant metastases (IRR = 0.58 [0.43-0.76]), even when race and age stratified. However, rates were higher in ACTUR for 40- to 59-year-old men (IRR = 1.25 [1.04-1.48]) and localized tumors (IRR = 1.16 [1.04-1.29]). Conclusion: Lower STS rates among servicemen may relate to better health and early detection and treatment of STS-associated conditions within the military health system, which provides universal care. Higher rates among 40- to 59-year-old servicemen may result from greater cumulative military-related exposures.