The committee identified several secondary studies that assessed the risk of cancer in veterans of Vietnam (Boscarino 1997) or veterans of any war (Schnurr et al. 2000; Spiro et al. 2006) who had PTSD. Boscarino (1997) found no increase in the presence of cancer in Vietnam veterans who had combat-related lifetime PTSD (n = 1067) compared with those without PTSD (n = 332) (OR 0.87, 95% CI 0.25-2.96, p = 0.817) after adjustment for a variety of demographic, social, and Army characteristics. Schnurr et al. (2000) assessed the prevalence of physician-diagnosed medical disorders and combat-related PTSD in 605 veterans of World War II and the Korean War. Veterans were screened for PTSD with the Mississippi Scale for Combat-Related PTSD. The hazard ratio for cancer was a nonsignificant 1.05 (95% CI 0.90-1.21) adjusted for age, smoking, alcohol consumption, and body-mass index (BMI) at study entry. Similar results were seen by Spiro et al. (2006), who examined the association between self-reports of PTSD and health conditions in 2425 veterans who participated in the Veterans Health Study conducted on outpatients at VA ambulatory-care clinics in 1993-1995. PTSD was assessed with the PTSD Checklist, measures of exposure to traumatic events were obtained, and a medical-history interview was conducted that asked about 22 conditions. An OR for cancer of 1.16 (95% CI 0.82-1.65) was seen in veterans with PTSD compared with veterans with depression and veterans with neither depression nor PTSD adjusted for age and for depression. The OR for skin cancer was an insignificant 1.24 (95% CI 0.85-1.79) for veterans with PTSD vs those without PTSD with or without comorbid depression.
In general, the three primary studies of male Vietnam veterans considered by this committee did not find statistically significant increases in cancer associated with deployment to Vietnam. The exception is the 50% increase in the risk of NHL in Vietnam veterans compared with era veterans; however, this risk does not appear to correlate with exposure to combat (Selected Cancers Cooperative Study Group 1990a). Two studies of cancer in female Vietnam veterans also failed to find an increased risk of all cancers or gynecologic cancers associated with serving in Vietnam. With respect to the specific question of concern in this review, studies of Vietnam veterans found no evidence that serving in a combat unit increases cancer risk. The studies included a sufficient observation period to detect most cancers that might result from deployment-related stressors experienced in Vietnam. The committee did not identify any secondary studies of cancer in Vietnam veterans.
There is no consistent evidence of a higher overall incidence of cancer in Gulf War veterans than in nondeployed veterans based on the four primary studies and nine secondary studies considered by the committee. Only one study found an increased (but nonsignificant) risk of any cancer in Gulf War veterans (McCauley et al. 2002b), but the sample was small, and there was no verification of the self-reported diagnoses. The other three primary studies and the secondary studies were all negative for an increased risk of cancer in Gulf War veterans. However, many of the Gulf War veterans are young for cancer diagnosis, and for most cancers the followup period after the Gulf War has probably been too short to expect their onset.
The incidence of and mortality from cancer in general and testicular cancer in particular have been assessed in cohort studies. Results regarding testicular cancer from three primary studies of Gulf War veterans were mixed: one study concluded that there was no evidence of an excess risk, a small registry-based study suggested that there may be an increased risk, and a third study of DoD hospitalization records found a slight increase in the first 5 months immediately after the war, but not in the following 2 years. Although the results are inconsistent,