Post-Traumatic Stress Disorder Symptoms from Multiple Stressors Predict Chronic Pain in Cancer Survivors.

Background: Despite the association between chronic pain and post-traumatic stress disorder (PTSD), little is known about the longitudinal course of pain and PTSD during cancer treatment. Objectives: We examined the prevalence of PTSD and chronic pain at three time periods in veterans with a diagnosis of cancer, and the relationship between the experience of pain and PTSD. Methods: Participants (N = 123) with oral-digestive cancers were recruited from the Veterans Healthcare System (age M = 65.31 and SD = 9.13; 98.4% male) and completed face to face interviews at 6, 12, and 18 months post-diagnosis. Measures included the Post-traumatic Stress Disorder Checklist-Stressor-Specific version (PCL-S), Primary care PTSD (PC-PTSD), and the Patient-Reported Outcomes Measurement Information System (PROMIS) Pain Impact Scale. Results: About one-third (26.8%) of the sample had chronic pain, defined as elevated pain at two time periods. About one-fifth (20.3%) endorsed symptoms of combat-related PTSD at 6 months, and 22.8% endorsed symptoms of cancer-related PTSD, exceeding a clinical cutoff for older adults (12 months = 21.1%, 18 months = 23.1%). Changes over time were observed for cancer-related PTSD symptom clusters of hyperarousal (F = 3.85 and p = 0.023) and emotional numbing (F = 4.06 and p = 0.018) with a statistically significant quadratic function increasing at 18 months. In logistic regression, individuals with both combat and cancer-related PTSD symptoms at six months had 8.49 times higher odds of experiencing chronic pain (χ2 = 25.91 and p < 0.001; R2 = 0.28). Conclusions: Persisting pain may be a concern in veterans with cancer. Individuals who have experienced traumatic events with persisting PTSD symptoms may be at elevated risk for chronic pain. Veterans with PTSD symptoms from both cancer and combat are at the highest risk to experience chronic pain.