This review assessed effects of exercise on persons with metastatic cancer on physical and quality of life outcomes. The authors concluded that exercise appeared to be beneficial for persons with metastatic cancer, but the evidence was inconclusive. The authors' conclusions and recommendations for further research appeared appropriate given the evidence and the diversity of the included studies in this review.

To assess the effects of exercise on persons with metastatic cancer.

MEDLINE, EMBASE, CINAHL, PsycINFO, Cochrane Central Register of Controlled Trials (CENTRAL), Cochrane Databases of Systematic Reviews and PEDro were searched from inception to May 2008. The search was restricted to studies in English or French. Search terms were reported. Reference lists of retrieved papers were handsearched. Experts were contacted for additional studies.

Studies that assessed the effects of exercise on persons with metastatic, advanced or palliative cancer were eligible for inclusion. Excluded studies were: studies of persons with lymphoma, melanoma or myeloma; studies where results of patients with metastatic cancer could not be separated from those with non-metastatic cancer; and newspaper editorials, critical reviews of individual articles and qualitative research studies. Studies were excluded if less than one-third of the sample had metastatic or advanced cancer. The terms used and stages of cancer were defined.

The baseline characteristics with respect to age, primary cancer site or type, cancer status, interventions, comorbidities and health status varied across the studies. Three of the studies included only persons with metastatic cancer. Five studies included samples in which 39% to 80% of the participants were described as having advanced or metastatic cancer or receiving treatment with palliative intent. An intervention could be solely exercise or exercise could be a component of the intervention. Types of exercise were aerobic and muscle strengthening and varied in type, frequency and intensity. All studies used physical and/or quality-of-life outcome measures. The tools used for measuring outcomes varied across studies.

Two independent reviewers screened titles, abstracts and full texts. Disagreements were resolved by consensus. Arbitration by a third reviewer was used for unresolved disagreements.

Two quality assessment tools were used depending on the study design. Randomised controlled trials (RCTs) were assessed using van Tulder and colleagues' criteria and case series were assessed using the case series criteria. For RCTs, quality was assessed on 11 quality domains. Case series were assessed using five quality domains. Each quality domain was evaluated by answering a list of questions with yes, no or not reported. A point was given only for a yes answer. Grades of recommendation from Oxford Centre for Evidence-Based Medicine were summarised for the studies by one reviewer and checked by a second reviewer.

Baseline and post-intervention levels of physical and quality of life outcome measures were calculated. Loss to follow-up in each arm was calculated.

Four reviewers extracted data. Each reviewer extracted data for two or three of the articles and the results were checked by a second reviewer. Disagreements were resolved by consensus.

The effects of exercise on physical and quality of life measures between pre- and post-intervention periods were combined in a qualitative synthesis.

Eight studies (n=501 participants) reported in 10 publications met the inclusion criteria. All three RCTs scored 8 out of 11 from van Tulder criteria. Four case series scored 3.5 out of 5 from case series criteria and one case series scored 2.5. None of the RCTs concealed treatment allocation or blinded the patients to the intervention. In the two RCTs that reported attrition, one reported 7% and the other 16%. Loss to follow-up in the case series ranged from 14% to 35%.

Exercise resulted in improved quality of life (three RCTs and four case series) and measures of physical performance (one RCT and three case series).

Adverse events were assessed in three of the eight studies and none were recorded.

Exercise may be beneficial for persons with metastatic cancer, but future research should clarify the optimal exercise dose parameters.

This review addressed a well-defined question in terms of participants, interventions, outcomes and study design. The search included appropriate electronic databases, but the restriction to studies in English and French meant that language bias could not be ruled out. Two or more reviewers selected trials, extracted data and assessed the quality of the included trials and resolved disagreements by consensus, which minimised bias and errors during the review process. Characteristics of the individual trials were presented. Validity was assessed with two quality tools dependent on type of study design. Potential sources of heterogeneity were explored qualitatively and reported. The presense of clinical heterogeneity and methodological limitations in the studies included in the review suggested that a narrative synthesis was appropriate.

The authors' conclusions and recommendations for further research appeared appropriate given the evidence presented and the diversity of the included studies in this review.

Practice: The authors stated that this review provided some support for exercise as an effective intervention for persons with metastatic cancer, although the evidence did not support specific exercise prescription for these patients.

Research: The authors stated that larger and more rigorous RCTs with homogeneous outcome measures were needed to investigate current gaps in the literature. Future research should clarify optimal exercise prescription, investigate all metastatic cancer sub-groups, determine acceptable attrition rates in this population, use valid and reliable outcome measures and consistent terminology in defining cancer status and clearly document adverse effects.

Not stated.

This is a critical abstract of a systematic review that meets the criteria for inclusion on DARE. Each critical abstract contains a brief summary of the review methods, results and conclusions followed by a detailed critical assessment on the reliability of the review and the conclusions drawn.