Evidence for a biopsychosocial model of cancer treatment-related pain.

The contribution of non-biomedical factors to the experience of pain in the cancer patient has not been well established. Although intensity of pain reports cannot be fully explained by extent of identifiable nociception or neuropathy, behavioral factors have been only modest predictors of cancer pain report. Most studies that have demonstrated associations between pain and behavioral factors were conducted with highly selected groups of patients with all data collected concurrently. Thus the predictive value of the behavioral factors has been indeterminable. In this study, 358 bone marrow transplant patients (196 male, 162 female) completed pretransplant biomedical, physical functioning, psychological and social evaluations. For 25 days following transplantation, patients completed daily visual analogue scale oral pain reports and nurses recorded opioid use. At least once a week oral medicine staff completed a standardized, validated measure of observable oral mucositis as a measure of nociception. Results indicated that psychological and social variables were significant predictors of pain in this sample. Distress, particularly distress specific to the transplant, was the strongest predictor, while self-efficacy and coping style were weaker, but significantly associated with pain report for either men or women. While the psychological and social variables were significant predictors of pain, most of the variance in pain report was explained by biomedical variables rather than psychological or social variables. These results are consistent with those of previous research and indicate that biopsychosocial associations predate the onset of pain, but are at best modest predictors of cancer patients who will report greater or lesser pain. Clinical applications and limits of these data are discussed, particularly in relation to emotional distress, coping style and the differences found in predicting pain in men and women.