Psychologic intervention improves survival for breast cancer patients
July, 2009
Commentary by Laureate Professor Rob Sanson-Fisher
The article
Anderson BL, Yang H-C, Farrar WB et al. Psychologic intervention improves survival for breast cancer patients - A randomized clinical trial. Cancer 2008;113(12):3450–8
The Reviewer
Rob Sanson-Fisher is Laureate Professor of Health Behaviour, at the Health Behaviour Research Group, School of Medicine and Public Health, University of Newcastle and is currently acting CEO of Cancer Institute NSW.
Abbreviations
Confidence Interval (CI) Hazard Ratio (HR)
Summary
Study design
This article describes a randomised controlled trial of 227 women with regional breast cancer (stage IIA, IIB, IIIA, IIIB) who were surgically treated and awaiting adjuvant therapy. The trial was previously reported on in 2004.1 Patients were randomised to a psychologic intervention plus assessment or assessment only. Groups were stratified by lymph node status/tumour size, hormone receptor status, menopausal status and spouse/partner status. The 1-year psychologic intervention (four months of weekly sessions followed by eight monthly sessions) was provided in small groups (eight to 12 patients), led by two clinical psychologists and included strategies such as relaxation training, healthy lifestyle advice, and communication skills. The primary endpoints were breast cancer recurrence and survival and the median follow-up was 11 years (range 7 – 13 years).
Findings
Patients in the intervention arm had improved recurrence-free survival, breast cancer-specific survival and overall survival compared to those in the assessment only arm:
- Recurrence-free survival HR 0.55; 95% CI: 0.32 to 0.96; p=0.03
- Breast cancer-specific survival HR 0.44; 95% CI: 0.22 to 0.86; p=0.02
- Overall survival HR 0.51; 95% CI: 0.28 to 0.93; p=0.03
The median time to recurrence and survival time for patients who died of breast cancer was 2.8 years and 6.1 years respectively for those in the intervention arm compared to 2.2 years and 4.8 years respectively for those in the assessment only arm.
Conclusion
The authors conclude that the psychologic interventions used in the trial were associated with improved survival for patients with regional breast cancer.
Commentary
What does this article add to existing clinical evidence in this area?
Those working in the psychosocial field hope that evidence will be produced showing that psychological based interventions will improve survival rates for cancer patients. These beliefs are shared by many patients and are reflected in the actions that some individuals take upon the diagnosis of cancer. The promise that by reducing stress, improving mood and other activities it is possible to increase the length of life as well as potentially its quality is immensely appealing. Psychological treatment, while not without potential side effects, would be seen as preferable to many of the medical treatment regimes currently prescribed and their side effects. The article by Anderson et al appears to offer evidence that for breast cancer patients psychological interventions did increase survival rates and reduce re-occurrence.
However, as in any research area, caution should be exhibited before concluding that changes in clinical practice should occur because of one study. The study is an important one and highlights some of the difficulties of undertaking credible work in this area.
How adequate was the methodology used in addressing the aim of this study?
Unfortunately, the authors do not discuss methodological issues, which may weaken the study, so it is worthwhile considering how these might affect interpretation of the findings:
Generalisablity. The study presents little information that can be used to estimate how representative the sample recruited might be of women with breast cancer in general. It is likely that there would be significant bias with a greater probability that women who would agree to be part of such a study are likely to be of higher social economic class and benefit from better health care delivery than is usually provided to those of low social economic class. This would be particularly applicable for an American sample.
Sample size. The authors have undertaken a difficult study with a highly complex intervention and long follow-up timeframe. While there has been a commendable effort to examine whether the groups are different and match on important variables, it is difficult to know whether this occurred effectively. The sample size is relatively small given the complexity of the intervention and outcomes. Large sample sizes are usually required for studies with clinical outcomes in order to allow for balance between intervention groups in a range of potential confounding factors, some of which may have been outside the study measures. While there were no statistically significant differences between groups on disease characteristics, the study may have had insufficient power to detect a difference between groups in factors that are already known to increase risk of recurrence. While the authors suggest, in their 2004 paper,1 that power calculations undertaken require a sample size of 200, it was not clearly articulated what outcome measures were used to make this assertion.
Potential contamination of the experimental conditions. While there was an attempt to find out whether patients in the control group had taken mood altering medication, it would be difficult to control and/or monitor attempts by patients to engage in psychological stress reduction and mood stabilising strategies. No assessment is made of the psychological, behavioural and health factors during the seven or more years from intervention completion through to assessment of recurrence and survival. For example, over the course of the follow-up period members of the control group may have engaged in intensive complementary therapies such as yoga, massage, meditation and relaxation. If this was the case, the reasons for the differences in life expectancy are not easily explained.
Credibility of the findings. While the authors postulate a reason for a potential linkage between stress reduction and mortality, this reviewer finds it difficult to understand how such psychological change leads to an increase in life expectancy. While the bio-psychological theory is described, it would have been more reassuring if a credible explanation about why this intervention does produce an increase in life expectancy had been offered. It is possible that changes in behaviour (smoking cessation, improved diet and exercise) may have been the key factors mediating survival rates. It is also puzzling how 26 sessions and 39 therapy hours could produce such an impact, when many studies of psychological therapies fail to find a long term impact on psychological outcomes.
Potential negative consequence from application of the findings. If these results were supported by other well designed randomised controlled trials, it would be interesting to consider the impact on breast cancer patients. If we assume that patients will be offered a psychological intervention designed to reduce stress and improve mood it may be that a recurrence of the disease could be seen as a failure of the individual to achieve such control of their psychological well-being. This burden of responsibility may be difficult to avoid, and may be a potentially negative side effect of this form of treatment.
What are the implications of this study for clinical practice in Australia?
For those who believe in the impact of psychological well-being on the length of life this is an encouraging paper. It is worth noting though that ‘one swallow does not a summer make’. As is the case for any research, there are a number of methodological limitations in the study which limit the credibility of the findings. While there may be a tendency to use these findings as evidence that psychological interventions do produce an increase in length of life; taking such a position without further more tightly controlled studies could be potentially erroneous and even harmful to patients’ care.
ACKNOWLEDGEMENTS
Dr Chris Paul, Centre for Health Research & Psycho-oncology (CHeRP) at the University of Newcastle, and Professor Catherine D’Este, Centre for Clinical Epidemiology and Biostatistics at the University of Newcastle.
References
1. Andersen BL, Farrar WB, Golden-Kreutz DM, et al. Psychological, behavioral, and immune changes after a psychological intervention: a clinical trial. J Clin Oncol 2004;22:3570–80.
Editor: Dr Anne Nelson, General Manager, National Breast and Ovarian Cancer Centre
Clinical Update – Breast Cancer Editorial Committee: Mr John Collins - Surgeon, Ms Jo Keyser - Specialist Breast Nurse, Dr Warwick Lee - Radiologist, A/Prof Liz Lobb – Senior Research Fellow, Dr Sue-Anne McLachlan - Medical Oncologist, Dr Sally Meade - Breast Surgeon, Dr Sue Pendlebury - Radiation Oncologist, A/Prof Martin Stockler - Medical Oncologist.
Disclaimer
Clinical Update - Breast Cancer is produced by National Breast and Ovarian Cancer Centre (NBOCC) and is intended to provide health professionals with timely expert commentary on new research in breast and ovarian cancer. Commentaries included in Clinical Update - Breast Cancer do not replace recommendations included in NBOCC clinical practice guidelines.
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