Risk of Lymphedema Is Associated With Obesity in Patients With Breast Cancer
Lymphedema related to breast cancer is one of the most distressing and feared late effects of breast cancer treatment.
Breast cancer is diagnosed in approximately 1.38 million women worldwide. Treatment advances have facilitated a 90% 5-year survival rate among those treated. Given the improved survival following breast cancer, more and more survivors face lifetime risk of developing late effects of cancer treatment.
Lymphedema, characterized by the abnormal swelling of one or more limbs, is most often caused by an obstruction or disruption in the lymphatic system during cancer treatment. It usually manifests after a latent period of 1 to 5, or even 20 years, after treatment. Consequently, lymphedema is a major health problem for many breast cancer survivors and negatively impacts their quality of life. Although no cure is currently available, the 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," says 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, existing research has produced conflicting findings. Some studies suggest obesity is a risk factor when defined as a body mass index (BMI) of 30 kg/m2 or more, whereas others claim risk is increased with a BMI as low as 25 kg/m2.
These discrepancies are due in part to study limitations, such as retrospective assessments, small sample sizes, and self-reports. To bridge the gap, Fu's team at NYUCN prospectively investigated patterns of obesity as they relate to lymphedema. The team's findings were published in the Journal of Personalized Medicine (doi:10.3390/jpm5030326).
"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," explained 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, and both 4 to 8 weeks and 1 year post-op.
Participants were given general instructions to maintain their pre-surgery weight. Among the 140 participants, 136 completed the study. More than 60% of the participants were obese (30.8%) or overweight (32.4%), while only 2 participants were underweight and approximately 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, 72.1% of the women maintained their presurgery weight and 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. This trend was observed throughout the study.
Obesity and overweight remain among women at the time of cancer diagnosis, and the patterns of obesity and overweight continue during the first year of treatment.
"General instructions on having nutrition-balanced and portion-appropriate diet and physical activities daily or weekly can be effective to maintain presurgery weight," said Fu. "Such general instructions may create less burden and stress to women when facing the diagnosis and treatment of breast cancer."