The influence of psychiatric intervention on cancer outcome remains a topic of considerable debate. We previously reported the survival benefits for 68 patients with malignant melanoma 5 to 6 years following their participation in a structured psychiatric group intervention. In this article, we report the effects of the intervention on disease outcome in these same patients at the 10-year follow-up.
In this univariate analysis, the survival and recurrence distributions for the intervention and control groups were estimated using the Kaplan-Meier method, and were tested for equality by the log-rank test. The multivariate analysis used the Cox proportional hazards regression model with the following prognostic factors: age, sex, Breslow depth, tumor site, and treatment status (ie, intervention group vs control group).
When analyzed as single covariates, differences between the intervention and control groups were not significant for outcome at the 10-year follow-up. However, being male and having a greater Breslow depth were predictive of poorer outcome. Analysis of multiple covariates also revealed that sex and Breslow depth were significant for recurrence and survival. In addition, participation in the intervention was significant for survival. After adjusting for sex and Breslow depth, participation in the intervention remained significant for survival.
These findings suggest that the survival benefit of the intervention has weakened since the 5- to 6-year follow-up; however, it has not entirely disappeared. At the 10-year follow-up, participation in the intervention remained predictive of survival when statistically controlling for the effects of other known prognostic indicators. Despite the potential health benefits, we do not propose that psychiatric intervention be used in lieu of standard medical care, but as one of its integral components.