Exercise as it relates to Disease/Physical activity intervention for middle age women living with metastatic breast cancer

This article is a critique of the paper "A randomized control trial of a physical activity intervention in women with metastatic breast cancer"

What is the background to this research?
Extensive research has focused on the positive effect exercise has for early stage breast cancer patients. Less research has been conducted on metastatic breast cancer. This should change as patients are beginning to live longer after diagnosis. Patients report significant side effects to their treatment such as fatigue, pain and low physical function. This can affect a patient's quality of life which may hinder their ability to recover and live a fulfilling life. Research has proven exercise helps alleviate symptoms accompanying early stage breast cancer but, is this relationship prevalent in metastatic breast cancer.

Where is the research from?
Jennifer Ligibel et al. examined the effect of exercise on metastatic breast cancer in Boston. Subjects were acquired from the Dana-Farber Cancer Institute and the Beth Israel Deaconess Medical Center. All authors have extensive experience in medical and breast cancer oncology and are professors at the Harvard Medical School. Given this wealth of knowledge and prestige it's assumed the authors of this study are credible and reliable.

What kind of research was this?
The study was a randomized controlled trial. Research has proven this type of study design to be the gold standard in testing safety and efficacy of new treatments. However, to yield meaningful results the study must be planned, conducted and analysed very methodically.

What did the research involve?
Eligibility required, having metastatic breast cancer, a life expectancy greater than twelve months, physical activity less than 150 minutes per week, and an Eastern Cooperative Oncology Group performance status of 0–1. Subjects were excluded if any contraindications for moderate-intensity exercise were present. 101 participants were randomly divided into an exercise and control group in a 1:1 ratio.

The exercise group partook in a 16-week supervised and home-based moderate intensity aerobic exercise intervention. The control group only received regular care during the intervention. Baseline and 16-week assessments were completed to show differences between the groups. Assessments included recording weekly physical activity minutes, self-reported physical functioning and quality of life assessed through the treatment of cancer quality of life questionnaire, cardiorespiratory fitness assessed through a modified Bruce ramp treadmill test, and fatigue through the functional assessment of chronic illness therapy fatigue scale.

The program was delivered via phone calls and in-person meetings with exercise physiologists. Phone calls occurred weekly and in-person meetings occurred weekly for the first month and monthly thereafter. Sessions targeted overcoming exercise barriers, reporting injuries, developing exercise self-efficacy, and performing exercise safely. One major goal was to increase weekly moderate intensity exercise to 150 minutes. All participants were given gym memberships, heart rate monitors, pedometers, and an exercise journal. Subjects recorded their average heart rates during bouts of exercise, daily steps and weekly minutes of exercise in their journals.

What were the basic results?
Table 1 shows the exercise group increased their physical activity minutes more than the controls. However, results are non-statistically significant. It also demonstrates on average, the exercise group didn't meet the goal of 150 minutes of exercise per week.

Table 2 shows the exercise group improved more compared to the control in both assessments. The difference in the physical functioning test was 4.79 compared to 0.93 and in the Bruce ramp treadmill test 0.61 minute compared to 0.37 minute. However, results are non-statistically significant.

Table 3 shows the exercise group slightly improved and the controls slightly decreased in quality of life. Fatigue assessment improvements were equal. However, results are non-statistically significant.

All tables demonstrate trends of improvement in the exercise group compared to the control, however, results are non-statistically significant. This indicates more research should occur to statistically support the trends shown in this study. One major limitation that likely affected results was attrition. Attrition was high with only 70% of the exercise group completing the study and 84% of the controls, causing a size difference between the groups. Due to high attrition and unequal group size, results were possibly affected.

What conclusions can we take from this research?
The study showed a trend of exercise improving physical functioning and quality of life of metastatic breast cancer patients. Although, results were non-statistically significant which may be caused by attrition and unequal group sizes. This research could underpin further exploration into this relationship.

Other research has explored the relationship between aerobic exercise, resistance exercise and yoga in this population. Lidia Delrieu et al. explored the response to an aerobic walking program. They found statistically significant improvements in a 6-minute walk test p<0.001, quadriceps strength p<0.001 and maintenance of quality of life. Study attrition was 2%. Jasmine Yee et al. investigated the response to a resistance training program. The study found improved fatigue scores in the intervention group +5.6 compared to the control which decreased -1.8. James Carson et al. explored the response to a yoga program. They found women who did the yoga program reported less pain p<0.03 and fatigue p<0.05 and higher levels of relaxation p<0.03. Study attrition was 28%. This research supports the positive trend found in Jennifer Ligibel et al. study. More consideration, was needed in regards to exercise type, study duration, and frequency of in-person sessions to produce the statistically significant results seen in other studies as these were differential points.

Practical advice
Jennifer Ligibel et al. study and other research discussed have shown that exercise is safe and beneficial for metastatic breast cancer patients. Exercises proven to be safe and beneficial include walking, yoga and basic resistance exercise such as chest press, squats and lunges performed at a moderate exercise intensity. Jennifer Ligibel et al. study was mainly home-based, whereas other studies which produced statistically significant results used a group-based approach and had lower attrition. Therefore, a group-based program may be more beneficial for this population than a home-based program.

Further information/resources
For further support or information visit;

Breast Cancer Network Australia

Cancer Australia

Young Survival Coalition