Effects on long-term survival of psychosocial group intervention in early-stage breast cancer: follow-up of a randomized controlled trial.

BACKGROUND: The promise of prolonged survival after psychosocial interventions has long been studied, but not convincingly demonstrated. This study aims to investigate whether a psychosocial group intervention improved long-term survival in women with early-stage breast cancer and investigate differences in baseline characteristics and survival between study participants and non-participants. METHODS: A total of 201 patients were randomized to two six-hour psychoeducation sessions and eight weekly sessions of group psychotherapy or care as usual. Additionally, 151 eligible patients declined to participate. Eligible patients were diagnosed and treated at Herlev Hospital, Denmark, and followed for vital status up to 18 years after their primary surgical treatment. Cox's proportional hazard regressions were used to estimate hazard ratios (HRs) for survival. RESULTS: The intervention did not significantly improve survival in the intervention group compared with the control group (HR, 0.68; 95% confidence interval (CI), 0.41-1.14). Participants and non-participants differed significantly in age, cancer stage, adjuvant chemotherapy, and crude survival. When adjusted, no significant survival difference between participants and non-participants remained (HR, 0.77; 95% CI, 0.53-1.11). CONCLUSIONS: We could not show improved long-term survival after the psychosocial intervention. Participants survived longer than nonparticipants, but clinical and demographic characteristics, rather than study participation, seem accountable for this difference.

In a randomized controlled trial, missing data led to biased results regarding anxiety.

BACKGROUND AND OBJECTIVE: Randomization does not protect against bias due to missing observations. In addition, different reasons for missing observations may lead to different invalid results. The purpose of this study was to illustrate how randomized intervention studies can be threatened by bias due to missing observations because of death or nonresponse. METHODS: A randomized clinical trial of the effect of psychosocial intervention on well-being after an operation for colorectal cancer was conducted in Denmark. Patients were interviewed 3, 6, 12, and 24 months after discharge from hospital. RESULTS: We found that the probability of nonresponse decreased with increasing anxiety score in the intervention group, but it increased with increasing anxiety score in the control group. This could lead to severe bias in an analysis of the effect of intervention on anxiety. Low physical functioning and low global health status and quality of life were related to an increased probability of dying before the next follow-up, and this association could explain the associations between anxiety and depression, respectively, and the probability of dying observed in crude analyses. CONCLUSION: Our study emphasizes the importance of performing specific missing data analyses in any study of well-being variables.