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. Clin Cancer Res; 16(12); 3270–8. ©2010 AACR.