What We're Reading: October 2024
Hiensch A, E. , Depenbusch, J., Schmidt, M,E., Monninkhof E,M., Pelaez, M., Clauss, D, et al. (2024) Supervised, structured and individualized exercise in metastatic breast cancer: a randomized controlled trial. Nature Medicine, 25, 1–10.
This randomised controlled trial evaluated the effects of a structured and individualized 9-month exercise intervention for people with metastatic breast cancer. The primary outcomes were health-related quality of life and fatigue after 6 months.
The exercise intervention was multimodal, including resistance, aerobic and balance exercises. The first 6 months involved two one-hour supervised group exercise sessions per week, and then in the final 3 months one of the supervised sessions was replaced with an unsupervised session. In addition, participants were encouraged to be physically active for at least 30 minutes per day.
Interestingly, of the 856 people invited to join the trial, only 357 were enrolled. Reasons for declining to participate included, in many cases, the study being too demanding or too much commitment, or people perceiving themselves to have poor physical or psychological health. Indeed, intensive exercise programs like this one are not always acceptable to, or aligned with the priorities of, people with life-limiting illnesses, and are often perceived as too burdensome. This is one of the reasons that in our INSPIRE trial, we are testing a rehabilitation intervention which is centred around people’s individual goals and concerns, where exercise is only one component.
Of those who participated in this trial, the average age was relatively young (55 years), many were highly educated (more than half had ‘academic education’) and most did not have any comorbidities, which is important to consider when interpreting the generalisability of the results. Nevertheless, the exercise intervention was found to be effective at improving both health-related quality of life and physical fatigue amongst the 285 participants who were evaluated after 6 months. Previous clinical trials of exercise interventions have mostly focused on people receiving curative cancer treatments, so this trial provides good-quality evidence of the benefit of exercise for people with metastatic breast cancer.
They screened 18359 articles and from them included 293 prospective randomised-controlled and 69 single arm-controlled trials from Jan 2008 – March 2019 testing the effect of rehabilitation interventions on 9 pre-determined primary functional outcomes. These included quality of life, ADL, fatigue, functional mobility, exercise behaviours, cognition, communication and sexual function Secondary and exploratory outcomes relating to function were also evaluated.
Most studies included in the review were conducted in people with breast cancer or in mixed cancer populations and were of moderate quality. Eighty statistically significant studies targeted QoL as a primary functional outcome. Measures of ADL, fatigue and functional mobility were each the target in 40 or more studies with significant findings. Fewer studies evaluated the remaining functional outcomes included in the review.
Interestingly for those following the INSPIRE project, they found that the most common reason for excluding a paper from the review was that no functional outcomes were reported in the original study. The authors deliberately excluded studies with physiological primary outcomes (e.g., maximum oxygen consumption or strength) as “these measures are frequently divorced from an individual’s capacity to function in their everyday lives”. The authors contend that cancer rehabilitation contributes much in terms of focusing holistically on “the person’s goals, strengths and contextual factors that address function and participation in everyday life”.
The authors also found few studies evaluating functional outcomes of rehabilitation intervention in palliative and end of life care settings. They suggest that while rehabilitation may impact on the rate of functional decline, rehabilitation studies in these settings may need different evaluation methods.
In their conclusion, they recommend that optimal measures of function are agreed across the care continuum.
The INSPIRE project aligns with the recommendations of the authors in this review, as our randomised controlled trial is evaluating the effectiveness of a rehabilitation intervention delivered for people in the palliative phase of their illness on quality of life, disability, personal goals, symptoms and health service use.
