Exercise as it relates to Disease/Effects of aerobic and resistance exercises in breast cancer patients receiving adjuvant chemotherapy

The following article is a critical appraisal of the report on the Effect of Aerobic and Resistance Exercise in Breast Cancer Patients Receiving Adjuvant Chemotherapy. This analysis has been conducted for a university assessment task for the unit of Health, Disease and Exercise at the University of Canberra.

What is the background to this research?
Breast Cancer is a deliberating disease that occurs mainly in women and if left un-treated can become a life threatening illness. The Australian Institute of Health and Welfare state that in 2008, 13,567 women were diagnosed with breast cancer in Australian with an average of 37 women being diagnosed with the illness each day. This form of cancer causes unfavourable changes in physical body functioning, body composition, quality of life, psychological functioning and for many female’s, physical appearance.

Treatment options for breast cancer include surgery, chemotherapy and radiation depending on the stage of breast cancer. Adjuvant chemotherapy is a form of treatment that is administered for three to nine months post surgically removing the cancer. This form of breast cancer treatment is commonly used when cancer cells have been found in the lymph node during the surgery, when the cancer was a large mass indicating metastasis (development of second growths at a distance from the primary cancer), in the presence of an aggressive and high-grade pathology or the tumour has negative hormone receptors. Adjuvant chemotherapy is not used for every breast cancer patient but it can provide a type of ‘insurance’ against the threat of other possible cancer cells that are infecting and damaging other areas of the body that are not visible through CAT scans, X-rays and lab results.

Muscle weakness and loss of physical strength is one of the more commonly reported side effects in breast cancer survivors. More then one-third of women experience sarcopenia through their journey of cancer and this impacts their overall health weakening the muscles, reducing quality of life and loss of essential nutrients and protein absorption which are used for energy production. Developments continue to find treatments that have fewer side-effects but in the meantime, there may be other ways to combat common side-effects such as through aerobic and resistance exercise, a well balanced and portioned diet and meditation and relaxation.

This article assesses the effects aerobic and resistance training have on cancer patients receiving adjuvant chemotherapy and how using these exercise interventions can improve overall health in these patients.

Where is the research from?
This study was conducted by a collective of researchers in Canada from the University of Alberta, Cross Cancer Institute Edmonton, Alberta Cancer Board, Ottawa Hospital Regional Cancer Centre, University of Ottawa Heart Institute, British Columbia Cancer Agency and the University of British Columbia. The report was published in the Journal of Clinical Oncology, a reputable peer reviewed medical journal containing research covering all aspects of oncology, in July 2007.

What kind of research was this?
The research used for this article was a randomised controlled trial. This form of research involves selecting the participants at random and using a computer designed program to randomly allocate each individual to a group. Using this type of trial allows all bias to be removed. The differing comparison groups allows the researchers to investigate if the variable of interest, when other things are controlled or exist in the control group, likely cause the measured changes. For the participant allocation, they were randomly assigned to either an aerobic exercise group, resistance exercise group or usual care group using a 1:1:1 ratio through a computer-generated program to do so.

What did the research involve?
For this research report, 242 breast cancer patients initiating adjuvant chemotherapy were used. 82 were assigned to usual care, 82 were assigned to supervised resistance exercise and 78 were assigned to supervised aerobic exercise for the duration of their chemotherapy. Participants that met the desired eligibility criteria were identified by their oncologist, then completed a questionnaire, physical fitness test and dual X-ray absorption scan. Physical functioning, body composition, psychological functioning and quality of life and how exercise affects these was the main purpose of the research and these were all measure pre and post experiment.

Each participant was assigned into a group and commenced exercise for the duration of their chemotherapy starting one to two weeks after beginning chemotherapy and completing exercise three weeks after the completion of their chemotherapy. The aerobic exercise group completed exercise three times per week on a cycle ergometer, treadmill or elliptical at 60% of their maximal oxygen consumption (VO2 max.). The resistance was raised by 10% every six weeks and the length of each session was increased by five minutes every three weeks until reaching 45 minutes in week 18.

The resistant exercise group trained three times per week performing two sets of eight to 12 repetitions of nine different exercises. The various exercises included were leg extension, leg curl, leg press, calf raises, chest press, seated row, tricep extension, bicep curl and modified/assisted chin ups. The resistance of each exercise was increased by 10% when a participant could complete more then 12 reps. The usual care group was not to complete any exercise throughout the duration of the experiment.

Each of the sessions were completed under supervision and included a warm up and cool down of light exercise and stretching for five minutes. The programs were designed by certified exercise specialists with previous experience in cancer rehabilitation. The researchers hypothesised the physiological and psychological benefits of the differing training groups and post experiment these were revaluated.

What were the basic results?
The results from this experiment showed positive attributes for those that were in either the aerobic or resistance training group.

Positive effects for the aerobic training group included an increase in peak oxygen consumption, increasing mitochondrial size and improving muscular work efforts and ATP production.

Positive effects for the resistance training group included greater improvement in upper and lower body strength which can be defined by the increase in muscle cross-sectional size and increased power production.

Both training groups demonstrated a positive muscular improvement, aswell as improvements in quality of life, resistance to fatigue, depression, self-esteem and anxiety.

What conclusions can we take from this research?
The use of both aerobic and resistance exercise during adjuvant chemotherapy treatment is highly beneficial to the patient. Participating in a form of exercise whilst undergoing treatment has proven to benefit the patient’s both physical and mental health.

Practical advice
Analysis of the article suggests that both aerobic and resistance exercise have positive effects on the patient during adjuvant chemotherapy treatment. Other studies have proven similar results with exercise being used in cancer rehabilitation to help improve quality of life, depression and anxiety.

Breast cancer patients have a unique and sensitive response to exercise whilst undergoing treatment but there are many research reports supporting bodily movement and use of aerobic and resistance exercise during treatment.

Future research on combining both resistance and aerobic exercise for patients receiving adjuvant chemotherapy could be assessed and could potentially have a more beneficial result. Any breast cancer patient should consult a certified exercise specialist with cancer rehabilitation experience first before undertaking any form of exercise.

Further readings

 * Journal of Clinical Oncology
 * Australian Institute of Health and Welfare
 * Adjuvant Chemotherapy