Weight gain can be a common side effect in breast cancer patients who undergo chemotherapy. Previous studies have shown that these patients typically gain between five and 14 pounds during treatment. Now, a new study has found that the cause of weight gain from chemotherapy may not be caused by overeating but by a lack of physical activity. The researchers found that women who underwent chemotherapy had notable changes in body composition. They suggest that exercise, especially resistance training in the lower body, be further studied as a possible way to prevent weight gain during chemotherapy.
In the study, lead researcher Wendy Demark-Wahnefried, PhD, RD, LDN of Duke University Medical Center and her colleagues compared 36 breast cancer patients who received chemotherapy as part of their treatment with 17 other women who underwent surgery and radiation therapy (localized treatment). The researchers found that the women who had chemotherapy gained an average of five pounds (approximately 2.1 kilograms) over the year versus an average of two pounds (approximately one kilogram) among the women who received localized treatment.
Of greater significance is the fact that Dr. Demark-Wahnefried and her colleagues observed notable changes in body composition among the women who had chemotherapy. "This was largely due to the fact that while women on chemotherapy gained weight, they also experienced slight decreases in muscle mass," Dr. Demark-Wahnefried told Imaginis.com. "This is a very distinctive pattern of weight gain since when most people gain weight, gains in muscle usually comprise 30% to 40% of the weight that is gained."
Because the chemotherapy patients gained only fat without increases in muscle mass, the researchers believe that the weight gain was not attributed to overeating. Rather, Dr. Demark-Wahnefried suggests that this change in body composition may be due to lack of physical activity as well as any direct or indirect effects of muscle mass. Changes in body composition are common as women age. However, these changes in the chemotherapy patients over the course of one year were equivalent to 10 years of normal aging, said Dr. Demark-Wahnefried.
The researchers believe that exercise can help prevent weight gain during chemotherapy, although they call for further research into what specific types of exercises would be most beneficial. Most current recommendations to relieve nausea and fatigue from chemotherapy involve aerobic exercises (such as walking), which are good for getting the legs in motion. However, Dr. Demark-Wahnefried suggests that resistance training exercises, especially those strengthening the legs and lower trunk (such as leg presses or squats), may be more beneficial in actually preserving muscle mass.
Physicians caution patients to check with their cancer treatment team before beginning an exercise program during or after treatment. Some women, particularly those who had axillary (underarm) lymph nodes removed during treatment, may be at risk for lymphedema (chronic swelling) of the arm. Lifting heavy arm weights or practicing other strenuous upper body exercises may not be appropriate.
- The study, "Changes in Weight, Body
Composition, and Factors Influencing Energy Balance Among Premenopausal Breast Cancer
Patients Receiving Adjuvant Chemotherapy," is published in the May 2001 issue of the Journal
of Clinical Oncology (Vol. 19, Issue 9). An abstract of the study is available at http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=
Retrieve&db=PubMed&list_uids=11331316&dopt=Abstract - The May 15, 2001 American Cancer Society News Today report, "Research Finds Women Gain Weight, Lose Lean Body Mass," is available at http://www2.cancer.org/zine/index.cfm?sc=001&fn=001_051520014_0
- To learn more about chemotherapy for breast cancer, please visit http://www.imaginis.com/breasthealth/chemo.asp
