Questions About Cancer? 1-800-4-CANCER

Clinical Trial Results

Summaries of Newsworthy Clinical Trial Results
  • Posted: 09/16/2009

Weight Lifting Does Not Exacerbate and May Improve Lymphedema Symptoms After Breast Cancer

Key Words

Breast cancer, survivor, lymphedema, weight lifting, exercise, late effects, radiotherapy. (Definitions of many terms related to cancer can be found in the Cancer.gov Dictionary.)

Summary

In a randomized phase III study, slowly progressive weight lifting did not aggravate limb swelling among breast cancer survivors with lymphedema. After a year of supervised weight training, those lifting weights increased strength and had fewer lymphedema exacerbations and symptoms.

Source

The New England Journal of Medicine, August 13, 2009 (see the journal abstract). (N Engl J Med. 2009 Aug 13;361(7):664-673)

Background

The lymph system is a network of vessels and tissues that carry lymph fluid throughout the body to help fight infections and other diseases. When the lymph system is damaged or blocked, fluid can build up in soft tissues, a condition known as lymphedema. Tissues with lymphedema are prone to infection, and many people with the condition experience discomfort, compromised function, and emotional distress.

Any cancer or treatment that disrupts the lymph system can cause lymphedema, although this condition is especially common in breast cancer patients because both surgery and radiation treatment for breast cancer can damage lymph nodes in the arm, shoulder, neck, and torso, Lymphedema is a progressive condition that can be managed but not cured; it can develop within days of treatment, or months or even years later.

Breast cancer survivors often avoid upper-body exercise out of concern that it will cause or worsen their lymphedema. However, in a recent clinical trial of breast cancer survivors whose armpit lymph nodes had been removed or irradiated, those who followed a 6-month weight-training regimen were no more likely than those who didn't follow the regimen to suffer from lymphedema. Moreover, some doctors are concerned that avoiding exercise could have harmful effects, such as slowing recovery or increasing disability after surgery.

The Study

Researchers recruited 141 breast cancer survivors who had been diagnosed with breast cancer between 1 and 15 years earlier and who had stable breast cancer-related lymphedema into this phase III randomized year-long clinical trial between October 2005 and March 2007. Half of the women were randomly assigned to participate in a weight lifting program, which included a year's membership at a community fitness center, instruction and initial supervision in weight lifting, and telephone reminders if they missed both of their scheduled sessions in any given week. The control group did not change their current exercise level during the year of the study, but they were offered the full year's membership and training after the study ended.

Patients in the weight lifting group received a training program that was phased in and supervised for the first 13 weeks of the year. The amount of weight (resistance) was gradually increased for patients whose lymphedema symptoms did not worsen. Those patients whose symptoms did worsen (lymphedema exacerbation) continued exercise for the lower body only until they were cleared by a lymphedema therapist to resume upper body exercise at the lowest possible resistance.

Limb volume was assessed by submerging the arm and hand in water and measuring the volume of water displaced. In addition, a lymphedema therapist assessed each participant at study entry and after 1 year, and participants completed a self-report survey that asked them about their lymphedema symptoms. Participants were assessed for lymphedema exacerbation if they reported a change in symptoms lasting at least a week or if they had changes of 5 percent or more in limb volume at 3 and 6 months, when interim measurements were made.

The study's principal investigator was Kathryn H. Schmitz, Ph.D., M.P.H., of the University of Pennsylvania and the Abramson Cancer Center in Philadelphia. Funding was provided by the National Cancer Institute and the National Center for Research Resources.

Results

The primary outcome was an increase in arm and hand swelling of at least 5 percentage points (as measured by displacement of water) after 1 year. The weight-lifting intervention did not increase the incidence of this outcome, which was seen in 8 of the 70 patients in the weight-lifting group and in 8 of the 69 patients in the control group.

Furthermore, weight lifting improved several secondary study outcomes. In particular, lymphedema exacerbation was half as frequent in the weight-lifting group as in the control group, and the severity of lymphedema symptoms showed a greater improvement in the weight-lifting group. Not surprisingly, patients in the weight lifting group had a greater increase in strength - lower body as well as upper body.

Comments

In an editorial that accompanied the study, Wendy Demark-Wahnefried, Ph.D., R.D., from M.D. Anderson Cancer Center in Houston, called these results "a substantial contribution to the available evidence to support weight lifting intervention." Because a substantial number of non-white women and women with a broad range of educational and occupational levels were included, she believes the findings are widely generalizable. Indeed, she noted that the intervention "may be particularly worthwhile in disadvantaged populations" in whom the burden of lymphedema may be greatest.

"We need more well-designed and conducted studies like this one looking at symptom management," said Julia Rowland, Ph.D., director of the Office of Cancer Survivorship in the National Cancer Institute's Division of Cancer Control and Population Sciences. "This particular study is important because it adds to the evidence about the multiple physical and psychosocial benefits of physical activity, and speaks to the question so many survivors have concerning what they can do to enhance their recovery and their health after treatment," said Rowland. "And we are even beginning to think that physical exercise may have an important role in actually increasing breast cancer survival."

Limitations

Despite the apparent value of this intervention, Demark-Wahnefried notes that follow-up research is needed to see if the program is cost-effective and can be disseminated effectively, "or whether it will instead sit on a shelf." Indeed, Schmitz and colleagues had considered the importance of dissemination when they delivered the weight lifting intervention in community fitness centers in a way "that could be replicated in YMCAs across the United States."

Participants could not be "blinded" as to their treatment assignment, which could have biased the reporting or assessment of symptoms. For example, patients in the intervention group might have been more aware of possible symptom changes that indicated the need to be evaluated for exacerbation.

Finally, this study does not indicate whether weight training can prevent the onset of lymphedema in breast cancer survivors who are at risk for the condition but have not yet developed it. Research addressing this question is currently under way.