Higher BMI Associated With Increased Risk of Breast Cancer–Related Lymphedema
Each year, about 1.38 million women worldwide are diagnosed with breast cancer. Advances in treatment have facilitated a 90% 5-year survival rate among those treated. Given the increased rate and length of survival following breast cancer, more and more survivors are facing a lifetime risk of developing late effects of cancer treatment that negatively impact long-term survival. In particular, breast cancer–related lymphedema is one of the most distressing and feared late effects.
Lymphedema is most often the result of an obstruction or disruption of the lymphatic system over the course of the cancer treatment. Lymphedema usually manifests after a latent period of several years post treatment. Consequently, lymphedema remains a major health problem affecting many breast cancer survivors, and exerts a tremendous negative impact on survivors’ quality of life. Although, at present, no surgery or medication can cure lymphedema, this condition can be managed with early and appropriate treatment.
“Obesity is an established risk factor not only for breast cancer–related lymphedema, but also for breast cancer occurrence, recurrence, and fatality,” said Mei R. Fu, PhD, RN, ACNS-BC, FAAN, Associate Professor of Chronic Disease Management at the New York University College of Nursing (NYUCN). “Accordingly, we believe obesity is a significant but modifiable risk factor for lymphedema.”
However, Dr. Fu noted that existing research has produced conflicting findings. For example, some studies suggest that obesity is a risk factor when defined as having a body mass index (BMI) of 30 kg/m2 or more, while others posit the risk is posed with as low a BMI as 25 kg/m2.
Such discrepancies are in part due to study limitations, such as retrospective assessments, small sample sizes, and self-reports. To bridge the gap, a team of NYUCN researchers led by Dr. Fu conducted a study designed to prospectively investigate patterns of obesity as they relate to lymphedema. The team’s findings were published by Fu et al in the Journal of Personalized Medicine.
Study Findings
“We determined the best way to quantify the relationship between obesity and lymphedema was to first examine obesity as it relates to lymph fluid level,” said Dr. Fu. The researchers followed 140 women through their first year of cancer treatment, measuring their lymph fluid levels—known as L-Dex values—and weight before their surgeries, 4 to 8 weeks postsurgery, and 1 year postsurgery.
General instructions were given to participants on maintaining presurgery weight. Among the 140 participants, 136 completed the study. More than 60% of the participants were obese (30.8%) or overweight (32.4%), whereas only two participants were underweight, and about 35% measured at normal weight. This pattern of obesity and overweight was consistent at 4 to 8 weeks and 12 months postsurgery.
At 12 months postsurgery, the majority of the women (72.1%) maintained presurgery weight. However, 15.4% had lost more than 5% of their weight; 12.5% of the women experienced more than a 5% increase in weight.
L-Dex values consistent with lymphedema were particularly prevalent in patients with a BMI greater than 30 kg/m2, and this trend was observed throughout the study.
“General instructions on having nutrition-balanced and portion-appropriate diet and physical activities daily or weekly can be effective to maintain presurgery weight,” said Dr. Fu. “Such general instructions may create less burden and stress to women when facing the diagnosis and treatment of breast cancer.”
The content in this post has not been reviewed by the American Society of Clinical Oncology, Inc. (ASCO®) and does not necessarily reflect the ideas and opinions of ASCO®.
