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Running head: EXERCISE AND BREAST CANCER The Correlation between Exercise and Breast Cancer Jana De Vries Ferris State University 1 EXERCISE AND BREAST CANCER 2 Abstract There is no doubt, in this day and age, that exercise belongs between the most important factors of remaining healthy and achieving longevity. Engaging in physical activity enables us to stay strong, contributes to our independence and creates a state of well-being. Additionally, it helps us to prevent or possibly postpone diseases and certain conditions. It has been proven, by many studies and researches, that any type of physical activity is beneficial and can have a very positive impact on our health status. Most importantly, exercise improves chances of our medical outcomes. This is especially true in the female and breast cancer cases. This manuscript examines and analyzes studies which were conducted to research the link between physical activity and breast cancer. Furthermore, it explores physical activity as a way to prevention of breast cancer, and as an important part of supportive/ adjunctive therapy during treatment and after surviving this disease. All studies presented are compared, explored, and suggestions are made for a future research. Keywords: Breast cancer, exercise, prevention, treatment, adjunctive therapy, studies EXERCISE AND BREAST CANCER 3 The Correlation between Exercise and Breast Cancer How does exercise affects prevention, treatment, and post-treatment (survivorship) of breast cancer? What is the correlation? Most of the research presented in this literature review attempted to answer these above stated questions. Breast cancer is the most common type of the cancer diagnosed among women. As recent studies suggested there is quite significant correlation between exercise and breast cancer. Furthermore, “The American Cancer Society assumes that around one-third of the yearly 500,000 malignant tumor-related deaths result from inactivity, high caloric intake, and overweight” (Graff & Wessely, 2010). Engaging in physical activity decreases the risk of the breast cancer and is recommended while undergoing cancer treatments to positively influence the outcomes of the treatment regimen. Furthermore, it is a great adjunctive therapy for breast cancer survivors that helps them with improvement of quality of life and get their strength back. However, “the question still remains unanswered which kind of activity in daily routine, in professional life, and in leisure time is preferable and possibly the most effective one” (Graf & Wessely, 2010). Exercise as prevention “The equivalent of 5 hours/ week of brisk walking was sufficient to achieve a reduced risk of breast cancer, an amount consistent with the U.S. government’s guidelines for adults to achieve additional health benefits beyond minimal activity” (Eliassen et al., 2010). This was a general consensus among all the studies. It has been agreed upon by experts that any type of exercise, especially brisk walking, is tremendously beneficial as cancer prevention. Furthermore, “Physical activity has been shown to decrease circulating estrogen levels in postmenopausal women, and lower circulating estrogen levels are associated with lower breast cancer risk” EXERCISE AND BREAST CANCER 4 (Eliassen et al., 2010). This was an interesting finding as many cancers are hormone-driven and female bodies could be labeled as hormone factory. It helped confirmed the link between exercise and hormone levels in females and therefore directed future treatments and medical interventions in the correct and more progressive direction. “The stronger association of physical activity with risk of postmenopausal compared with premenopausal breast cancer hints at a biological mechanism” (Ogunleye & Holmes, 2009). Strong correlation was established and validated by recent studies performed. Nevertheless, past research was mostly done on postmenopausal women so additional research is required for premenopausal group because findings could be quite significant. There is no doubt that engaging in proper lifestyle will help a person to prevent or delay onset of many diseases, (such as diabetes or cardiac disease). Increasingly, there is a trend which pinpoints proper lifestyle as the number one factor to prevent and combat cancer. There are some uncontrollable factors to getting cancer (e.g. genetic predisposition), however according to researchers Khan, Afaq, & Mukhtar (2010) “we can modify our lifestyle to reduce enhanced threat of cancer and these modifications include a healthy diet, weight management, regular exercise, reduction in alcohol consumption and smoking cessation.” Exercise as adjunctive therapy Any type of exercise as an adjunctive therapy is very important while undergoing cancer treatment. It has been suggested, to all cancer patients, to engage in physical activity which would be tolerable to them. This would help to decrease side-effects such as lymphedema, depression, neuropathy, bone loss, and decrease in functional capacity. “These side-effects ultimately led to impairments in health-related quality of life” (Eyigor et al., 2010). In many cases, “systematic review and meta-analysis have shown that exercise (aerobic, resistance, Tai EXERCISE AND BREAST CANCER 5 Chi Chuan) have a positive effect on quality of life, cardio-respiratory fitness and fatigue” (Eyigor et al., 2010). The new, break-thru study was performed on pilates exercise and its effect on breast cancer. It is important to mention this study, as many of them (in the past) did not concentrate on the particular type of physical activity. There has been sixty patients (age 18-75) participating in the study and were selected through strict criteria. The study concluded that even pilates increased flexibility of cancer patients (more so than any other type of exercise) “significant differences were not observed and the results of this study needs to be supported by future studies” (Eyigor et al., 2010). Another study concentrated on the weight gain and survivorship connection to the breast cancer. According to Djuric, Ellsworth, Weldon, Ren, & Resnicow (2010) “Weight gain is an important concern that impacts on breast cancer outcomes and general health in survivorship.” This specific study was exploring “whether or not women could comply with a weight control program that is initiated at the beginning of chemotherapy for breast cancer” (Djuric et al., 2010). The researchers used low-fat diet with abundance of fruit and vegetables and moderate physical activity as means to achieve their results. It could have been described as life-style modification study or life-style approach study. Its results were very positive as many patients were able to maintain their desired weight when monitored. However, the drop- out rate was 25 percent, which somewhat skewed the results. Exercise post-treatment “Improved functional status is a primary goal in the rehabilitation of cancer survivors” (Knols et al., 2010). One of the worst complications of the breast cancer is lymphedema. “Vigorous upper-extremity activity and/or exercise have traditionally been proscribed for breast EXERCISE AND BREAST CANCER 6 cancer patients and survivors because of the risk of developing lymphedema” (McNeely et al., 2009). Not just this particular study (by McNeely et al.), but other studies in this literature review agreed that it is important to keep the lymph circulating and let muscles act as a big pump in order to achieve positive outcomes. This should also allow for improved cardiac function and increased joint mobility. Compared to other studies on lymphedema, this study did not used water-displacement volumetry to measure limb circumference. This used to be the gold standard. Other equipment called Perometer “has been shown to be highly reliable, and has been validated by comparison with circumferential and water-volume measurements” (McNeely et al., 2009). Because of that this study was quite innovative. The study added to the past research that “response to acute upper-extremity exercise in terms of upper-limb volume and symptoms is similar between affected and unaffected limbs in women with breast cancer who perform regular upper-extremity exercise” (McNeely et al., 2009). Conclusion The literature review of this topic presented by various researchers showed the evidence of the impact of exercise on the prevention of the breast cancer. Most of the evidence focused on decreasing the risk of the breast cancer, the benefits of physical activity and healthy life-style. Furthermore, it has been suggested that increased physical activity has a positive effect on cancer patients and cancer survivors. It has been determined that it prolongs life, prevents recurrence of the cancer and complications of the treatment (e.g. lymphedema). It can be said that exercise and its effect was common denominator of all the studies. The studies which were conducted in the past examined and analyzed this topic mostly as a whole, but detailed study on particular types of the exercises are yet to be performed. There is EXERCISE AND BREAST CANCER 7 not enough information pertaining to this issue. “Although greater activity has been related to lower breast cancer risk, important details remain unclear, including type, intensity, and timing of activity, and whether the association varies by subgroup” (Eliassen et al., 2010). Further research on different type of exercise and its impact is warranted. Hopefully, this could bring some very valuable results and knowledge regarding new interventions and their application into the lifestyle of the patients, their treatments and therapy. “The diversity in the activities prescribed (e.g., walking, strength and endurance, interventions with or without counseling) reflects the absence of consensus on the optimal activity program for cancer survivors” (Knols et al., 2010). Additionally, it is author’s opinion, that it is important to re-evaluate different subgroups when researching how exercise impacts them. From the presented articles, it is clear, that only limited amount of the research was performed on premenopausal women, therefore results are inconclusive. “The majority of studies have focused on postmenopausal breast cancer, although there is also some evidence for a protective effect of physical activity on premenopausal disease” (Parkin, 2010). Also, it would be interested to see how the results compare in Caucasian, African-American, Asian and other populations. To conclude this literature review, it is obvious that exercise and healthy lifestyle are the most powerful warriors when it comes to cancer. This was demonstrated by all the research and studies presented. Furthermore, they all loosely followed “American Cancer Society recommendations for the prevention of tumor diseases” as mentioned by Eliassen, Hankinson, Rosner, Holmes, & Willett (2010). Recommendations are as followed: 30-60 min exercise on at least 5 days per week Energy balance control EXERCISE AND BREAST CANCER Well-balanced nutrition 5 servings of fruits and vegetables per day Moderate alcohol consumption (not more than 1 alcoholic drink for women and 2 8 drinks for men per day) It can be said that patients are most definitely in charge of their health and can positively influence their status and medical outcomes. Even with cancer diagnosis, exercise and modified lifestyle enables them to change their destiny! EXERCISE AND BREAST CANCER 9 References Djuric, Z., Ellsworth, J.S., Weldon, A. L., Ren, J., Richardson, C. R., Resnicow, K., et al. (2011). A diet and exercise intervention during chemotherapy for breast cancer. Open Obes J, 3, 87-97. doi: 10.2174/1876823701103010087 Eliassen, A. H., Hankinson, S. E., Rosner, B., Holmes, M. D., & Willett, W. C. (2010). Physical activity and risk of breast cancer among postmenopausal women. Arch Intern Med, 170(19), 1758-1764. doi: 10.1001/archintenrnmed.2010.363 Eyigor, S., Karapolat, H., Yesil, H., Uslu, R., & Durmaz, B. (2010). Effects of pilates exercizes on functional capacity, flexibility, fatigue, depression and quality of life in female breast cancer patients: a randomized controlled study (Vol. 46). Graf, C., & Wessely, N. (2010). Physical activity in the prevention and therapy of breast cancer. Breast Care (Basel), 5 (6), 389-394. doi: 10.1159/000322650 Khan, N., Afaq, F., & Mukhtar, H. (2010). Lifestyle as risk factor for cancer: evidence from human studies. Cancer Lett, 293(2), 133-143. doi: 10.1016/j.canlet.2009.12.013 Knols, R. H., de Bruin, E. D., Shirato, K., Uebelhart, D., & Aaronson, N. K. (2010). Physical activity interventions to improve daily walking activity in cancer survivors. BMC Cancer, 10, 406. doi: 10.1186/1471-2407-10-406. McNeely, M. L., Campbell, K. L., Courneya, K. S., & Mackey, J. R. (2009). Effect of acute exercise on upper-limb volume in breast cancer survivors: a pilot study. Physiother Can, 61(4), 244–251. doi: 10.3138/physio.61.4.244. Ogunleye, A. A., & Holmes, M. D. (2009). Physical activity and breast cancer survival. Breast Cancer Res, 11(5), 106. doi: 10.1186/bcr2351. EXERCISE AND BREAST CANCER 10 Parkin, D. M. (2011). 9. Cancers attributable to inadequate physical exercise in the UK in 2010. Br J Cancer, 105 Suppl 2, S38-41. doi: 10.1038/bjc.2011.482 EXERCISE AND BREAST CANCER 11