Psychological and endocrine factors and pain after mastectomy

Background: This prospective study was designed to examine the associations of demographic, clinical, psychological and neuroendocrine factors with acute and chronic post-operative pain following partial mastectomy. Methods: Sixty-four female patients scheduled for partial mastectomy were enrolled. Pre-operative anxiety/depression was assessed, using the Hospital Anxiety and Depression Scale (HADS). Pre-operative 24-h urinary cortisol levels were measured 2 days before surgery. Post-operative pain was examined using a visual analog scale (VAS) for acute pain on 0-2 post-operative day (POD), and a short-form McGill Pain Questionnaire for chronic pain at 6 months after surgery. In the last 29 subjects, post-operative 24-h urinary cortisol levels were also measured on 0 POD and were subjected to correlation analysis. Results: Multivariate logistic regression analysis revealed that lower pre-operative cortisol secretion and greater pre-operative anxiety were significantly associated with an increased risk of moderate to severe acute post-operative pain [Odds Ratio (95% Confidence Interval); 0.96 (0.92-0.98), and 1.24 (1.04-1.54)], and that patients with greater pre-operative anxiety and moderate to severe acute pain were more likely to develop chronic post-operative pain [OR (95% CI); 1.63 (1.23-2.40), and 5.07 (1.30-24.6)]. Correlational analysis demonstrated that the post-operative cortisol level was inversely correlated with pre-operative anxiety and the intensity of acute post-operative pain (r = -0.40, p < 0.05, and r = -0.50, p < 0.01), but not with the intensity of chronic pain. Conclusions: This study confirms that pre-operative anxiety is associated with both acute and chronic post-operative pain after partial mastectomy. It also suggests that lower perioperative cortisol secretion might be associated with greater acute post-operative pain. Significance: Although the associations between psychological stress/stress hormone levels and chronic post-operative pain remain to be determined, pre-operative psychological stress and perioperative cortisol levels are correlated with acute post-operative pain.