Distress reduction from a psychological intervention contributes to improved health for cancer patients

Abstract

Purpose: Psychological interventions are efficacious in reducing emotional distress for cancer patients. However, it is not clear whether psychological improvements are, in turn, related to improved health. A clinical trial tests whether a psychological intervention for cancer patients can do so, and also tests two routes to achieve better health: (a) reducing patients' Emotional Distress, and/or (b) enhancing their functional immunity.

Methods: Post-surgery, 227 breast cancer patients were randomized to intervention or assessment only Study Arms. Conducted in small groups, intervention sessions were offered weekly for 4 months and followed by monthly sessions for 8 months. Measures included psychological (distress), biological (immune), and health outcomes (performance status and evaluations of patient's symptomatology, including toxicity from cancer treatment, lab values) collected at baseline, 4 months, and 12 months.

Results: A path model revealed that intervention participation directly improved health (p<.05) at 12 months. These effects remained when statistically controlling for baseline levels of distress, immunity, and health as well as sociodemographic, disease, and cancer treatment variables. Regarding the mechanisms for achieving better health, support was found for an indirect effect of distress reduction. That is, by specifically lowering intervention patients' distress at 4 months, their health was improved at 12 months (p<.05). Although the intervention simultaneously improved patients' T-cell blastogenesis in response to phytohemagglutinin (PHA), the latter increases were unrelated to improved health.

Conclusion: A convergence of biobehavioral effects and health improvements were observed. Behavioral change, rather than immunity change, was influential in achieving lower levels of symptomatology and higher functional status. Distress reduction is highlighted as an important mechanism by which health can be improved.

Fig. 1.

Experimental design and study flow diagram.

Fig. 2.

Significant Group × Time interaction effects for the Karnofsky Performance Status (KPS) and Symptoms/Signs.

Fig. 3.

Path model of longitudinal relationships among Cancer Stress, psychological intervention (Study Arm), Cancer Stress × Study Arm interaction, Emotional Distress, Immunity, and Health Status outcomes. The model accounts for initial levels of Emotional Distress, Immunity, and Health Status. Resulting path weights are provided where statistically significant (p < .05). Study Arm had a positive effect on 4-month Immunity. Study Arm also interacted with initial cancer-related stress (Study Arm × Cancer Stress), producing greater reductions in 4-month Emotional Distress for intervention women with high initial levels of Cancer Stress. By 12 months, Study Arm had a direct positive effect on Health Status. Four-month Emotional Distress, but not 4-month Immunity, was a significant predictor of Health Status. The indirect effect of the Study Arm × Cancer Stress interaction on 12-month Health Status via 4-month Emotional Distress was significant (z = 2.11, p = .04).