Biobehavioral, immune, and health benefits following recurrence for psychological intervention participants

Abstract

Purpose: A clinical trial was designed to test the hypothesis that a psychological intervention could reduce the risk of cancer recurrence. Newly diagnosed regional breast cancer patients (n = 227) were randomized to the intervention-with-assessment or the assessment-only arm. The intervention had positive psychological, social, immune, and health benefits, and after a median of 11 years the intervention arm was found to have reduced the risk of recurrence (hazard ratio, 0.55; P = 0.034). In follow-up, we hypothesized that the intervention arm might also show longer survival after recurrence. If observed, we then would examine potential biobehavioral mechanisms.

Experimental design: All patients were followed; 62 recurred. Survival analyses included all 62. Upon recurrence diagnosis, those available for further biobehavioral study were accrued (n = 41, 23 intervention and 18 assessment). For those 41, psychological, social, adherence, health, and immune (natural killer cell cytotoxicity, T-cell proliferation) data were collected at recurrence diagnosis and 4, 8, and 12 months later.

Results: Intent-to-treat analysis revealed reduced risk of death following recurrence for the intervention arm (hazard ratio, 0.41; P = 0.014). Mixed-effects follow-up analyses with biobehavioral data showed that all patients responded with significant psychological distress at recurrence diagnosis, but thereafter only the intervention arm improved (P values < 0.023). Immune indices were significantly higher for the intervention arm at 12 months (P values < 0.017).

Conclusions: Hazards analyses augment previous findings in showing improved survival for the intervention arm after recurrence. Follow-up analyses showing biobehavioral advantages for the intervention arm contribute to our understanding of how improved survival was achieved.

Figure 1

Study flow from the time of RCT accrual through a median of 11 years of follow-up. Note: Patients designated as “lost follow-up” are known to be alive; cancer status is not known, however.

Figure 2

Predicted cumulative survival after recurrence of 62 breast cancer patients according to study arm, Intervention versus Assessment only.

Figure 3

A) Significant study arm by time interaction showing a significantly greater improvement (reduction) in negative mood for the Intervention patients following the baseline distress of recurrence diagnosis.; B) Significant study arm effect with the Intervention arm reporting higher social support at baseline than the Assessment arm (P=0.001). The time effect indicates a significant decline in social support for the Assessment arm (P=0.002).; C) Significant study arm by time interaction showing greater NKCC for the Intervention arm 12 months after recurrence diagnosis. NKCC was expressed as the mean of standardized scores from six E:T ratios.