October 2014 Issue

Breast Cancer and Exercise
By Jennifer Van Pelt, MA
Today’s Dietitian
Vol. 16 No. 10 P. 80

October is National Breast Cancer Awareness Month, when pink ribbons remind women to schedule their mammograms and honor those who have died from or survived breast cancer. According to the National Cancer Institute, one in eight American women (12.3%) will develop invasive breast cancer during her lifetime.

This year, breast cancer will be the most common cancer in women, with more than 232,000 new cases diagnosed. The impact of a cancer diagnosis is tremendous for patients and their families. Chemotherapy, radiation therapy, and surgery take their toll, and posttreatment complications, such as lymphedema and fatigue, can affect quality of life long after treatment ends. And cancer recurrence is an ongoing fear for the approximately 2.8 million breast cancer survivors in the United States. The American Cancer Society (ACS) estimates that breast cancer will recur in 10% to 20% of survivors.

Breast cancer isn’t as fatal as other cancers in women (eg, lung and colon). Survival rates are relatively high (ranging from 72% to 100%) when the cancer is caught before it metastasizes, according to the ACS. Therefore, chances are at some point in your work, you’ll encounter female clients who have been diagnosed with or who have survived breast cancer. A cancer diagnosis that hits close to home for the client or a family member or good friend generally catalyzes lifestyle changes—eating better, exercising, or quitting smoking. For those not personally affected by cancer, increased media exposure of genetic testing may have generated a mindset that lifestyle factors don’t matter if you’ve got the breast cancer gene.

But recent research says exercise does matter. It can help prevent breast cancer and even help alleviate treatment side effects. The World Cancer Research Fund/American Institute for Cancer Research (WCRF/AICR) has reviewed evidence related to physical activity and cancer prevention and issued evidence-based guidelines for breast cancer prevention related to nutrition, body size, and physical activity. In its overall 2010 report on cancer prevention, the organization concluded, “the evidence on physical activity and the risk of cancer, which has continued to accumulate since the early 1990s, shows or suggests that regular, sustained physical activity protects against cancers of some sites. These include colon cancer and female hormone-related cancers, independently of other factors such as body fatness … Physical activity probably protects against postmenopausal breast cancer; the evidence suggesting that it protects against premenopausal breast cancer is limited.” For more information, the Breast Cancer 2010 Report can be downloaded at www.dietandcancerreport.org/cancer_resource_center/downloads/cu/Breast-Cancer-2010-Report.pdf. New research evidence is evaluated at regularly scheduled intervals by the WCRF/AICR. An updated report on breast cancer recurrence is expected by the end of this year.

The WCRF/AICR recommendations for physical activity for cancer prevention are as follows:
• Be moderately physically active, equivalent to brisk walking for at least 30 minutes every day.1

• As fitness improves, aim for 60 minutes or more of moderate or 30 minutes or more of vigorous physical activity every day via occupational, household, and/or recreational activities.

• Limit sedentary habits such as watching television.

Latest Research
Studies published since these reports were released confirm and strengthen the conclusion that exercise can aid in breast cancer prevention, and include the following:

• A systematic review published in February 2014 evaluated 21 studies and concluded that physical activity may reduce the risk of breast cancer, especially in postmenopausal women.2

• An analysis of data on 1,110 breast cancer patients and 1,172 cancer-free control patients from a Canadian screening mammography program and cancer registry found that moderate-to-vigorous recreational physical activity (about three hours per week of activity equivalent to running) for those older than 35 was more strongly associated with reduced cancer risk compared with the same level of activity earlier in life. And moderate-to-vigorous household activities (equivalent to about 24 hours per week of moderate housework) were associated with reduced risk at all ages.1 

• A review of evidence on exercise for breast cancer prevention and rehabilitation noted a 20% to 40% reduction in breast cancer risk for women who participated in moderate-to-vigorous exercise three to fives times per week. A 50% reduction in risk of breast cancer death after diagnosis also was found in physically active women compared with sedentary women.3

Engaging in regular exercise also has been shown to reduce cancer-related fatigue and depression, improve quality of life, and increase immune function, strength, and cardiorespiratory fitness in breast cancer survivors.3-5 These published studies evaluated standard aerobic and resistance training during breast cancer treatment. Yoga, Pilates, and tai chi/qigong also have been shown to benefit cancer patients and survivors by improving mood, reducing fatigue, and increasing shoulder range of motion after treatment.

As part of their comprehensive cancer treatment services, many hospitals are offering exercise programs designed for breast cancer patients and survivors. Small group exercise provides the opportunity for sharing experiences with other patients and survivors, thereby contributing psychosocial benefits. For those clients who may be self-conscious after treatment or have other limitations, home exercise DVDs are available at the following websites: http://www.strengthandcourage.net, http://movingforlife.org/order-dvd.htm, http://www.merrithew.com/shop/ProductDetail/DV81142_Dvd-Breast-Cancer-Rehab-On-Equipment, and http://www.yogaforcancer.com/shop/yoga-dvds/yoga-for-breast-cancer.

For those in the allied health and fitness fields, new certifications in exercise for cancer patients have been developed and may be of interest, including the American College of Sports Medicine in collaboration with the American Cancer Society (http://certification.acsm.org/acsm-cancer-exercise-trainer) and the Cancer Exercise Training Institute (http://www.thecancerspecialist.com/ceti-new/default.aspx).

— Jennifer Van Pelt, MA, is a certified group fitness instructor and health care research analyst/consultant in the Reading, Pennsylvania, area.

1. Kobayashi LC, Janssen I, Richardson H, Lai AS, Spinelli JJ, Aronson KJ. Moderate-to-vigorous intensity physical activity across the life course and risk of pre- and post-menopausal breast cancer. Breast Cancer Res Treat. 2013;139(3):851-861.

2. Gonçalves AK, Dantas Florencio GL, Maisonnette de Atayde Silva MJ, Cobucci RN, Giraldo PC, Cote NM. Effects of physical activity on breast cancer prevention: a systematic review. J Phys Act Health. 2014;11(2):445-454.

3. Volaklis KA, Halle M, Tokmakidis SP. Exercise in the prevention and rehabilitation of breast cancer. Wien Klin Wochenschr. 2013;125(11-12):297-301.

4. Zou LY, Yang L, He XL, Sun M, Xu JJ. Effects of aerobic exercise on cancer-related fatigue in breast cancer patients receiving chemotherapy: a meta-analysis. Tumour Biol. 2014;35(6):5659-5667.

5. Battaglini CL, Mills RC, Phillips BL, et al. Twenty-five years of research on the effects of exercise training in breast cancer survivors: A systematic review of the literature. World J Clin Oncol. 2014;5(2):177-190.