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Dietary Management of Breast Cancer-Associated Lymphedema
Abstract & Commentary
By William B. Ershler, MD, Editor, INOVA Fairfax Hospital Cancer Center, Fairfax, VA; Director, Institute for Advanced Studies in Aging, Washington, DC.
Synopsis: In a prospective clinical trial of women with lymphedema following breast cancer treatment, two dietary interventions were compared to control diet in alleviating arm swelling. There was an association of weight loss and reduced swelling. However, no significant reduction was observed in those who were placed on the low-fat diet, unless there was associated weight loss. Thus, manipulating dietary composition alone was not shown to influence lymphedema severity.
Source: Shaw C, et al. Randomized controlled trial comparing a low-fat diet with a weight-reduction diet in breast cancer-related lymphedema. Cancer. 2007;109:1949-1956.
Despite trends toward less radical surgery for primary breast cancer, ipsilateral upper extremity lymphedema occurs in 20-40%of cases.1 Obesity is considered a predisposing factor. In the current report three different dietary approaches were prescribed to test the hypothesis that low fat diets would reduce arm swelling, even in the absence of diet-induced weight loss. These included: (1) low total calorie (1000-1200 Kcal/day); (2) low fat (20% of total energy); and (3) control (no dietary adjustment).
A total of 64 women with breast cancer-associated lymphedema were randomized to 1 of 3 dietary programs for 24 weeks. The primary outcome measure was arm volume at 24 weeks. Results showed significant reductions in body weight (P = 0.006), body mass index (P = 0.008), and skinfold thickness, measured at 4 sites (P = 0.044) in the weight-reduction and low-fat groups compared with controls. However, there was no significant change in arm volume in either of the dietary groups. Nonetheless, for those who lost weight, irrespective of dietary group, there was a significant reduction in excess arm volume (P = 0.002).
Dietary interventional studies are often problematic, even when motivation is strong, such as one might imagine it would be if control of troublesome lymphedema were the desired outcome. Dr. Shaw and colleagues, hopeful to demonstrate adjustment in dietary content (ie, low fat) rather than a simple low-calorie weight loss diet would produce the desired effect. What they found, however, was that in order to demonstrate this, the study would have to include approximately 10 times the number of subjects. Those who were assigned to the low calorie diet lost weight, but not as much as expected on the basis of the prescribed diet. Those on the low fat diet were advised to supplement their caloric intake with carbohydrate and protein and were not expected to lose weight, but they did. In sum, although there were interesting trends, no conclusions about dietary composition and relief of lymphedema can be drawn from the current research.
That stated, it is gratifying to see that examining the data just on the basis of weight lost, irrespective of assigned treatment (control, low calorie or low fat) demonstrated a fairly robust correlation of weight loss and reduction in lymphedema. Not a novel finding (refs), but reassuring nonetheless.
In these days where breast conserving surgical approaches are becoming more common and deep axillary lymph node dissections less, it is likely that mastectomy associated lymphedema will be found to be less prevalent. Certainly, to repeat this trial in an appropriately powered study, a sample size of approximately 500 patients would be required, unlikely without a large scale, multi-site undertaking. For a problem that is diminishing in prevalence and an intervention that is so difficult to regulate, the limited resources available for clinical research are likely to be redirected. This provides little consequence for those with this aggravating complication of breast cancer therapy. For them, perhaps the most prudent recommendation would be to make efforts to achieve ideal body weight by a combination of diet and exercise. For those already close to ideal body weight, manipulation of dietary intake by reducing fat intake might be of some benefit, but this, of course, remains unproven.
1. Clark B, et al. QJM. 2005;98:343-348.
2. Arrault M, Vignes S. Bull Cancer. 2006;93:1001-1006.
3. Bertelli G, et al. Surg Gynecol Obstet. 1992;175:455-460.