Lymphedema is buildup of fluid that causes swelling. It can be a lasting side effect of removing lymph nodes during breast cancer surgery.
To avoid developing the condition or making it worse, the vast majority of the 2.4 million breast cancer survivors in the U.S. are typically advised against lifting children, heavy bags, or anything else weighing more than 5 pounds.
But the studies challenge such advice.
The findings "do not mean women can just go out, buy a set of weights and start their own rehabilitation program," says researcher Kathryn Schmitz, PhD, MPH, associate professor of epidemiology and biostatistics at the University of Pennsylvania School of Medicine.
What "breastcancer survivors should do is go to their physician and insist on getting a prescription for physical therapy. The physical therapist can evaluate them and develop a safe weight lifting program," Schmitz tells WebMD.
The new study was presented at the San Antonio BreastCancer Symposium and published online in the Journal of the American Medical Association.
The study involved about 150 breast cancer survivors who had their cancer diagnosed one to five years previously. All had two or more lymph nodes removed, and none had signs of lymphedema when they entered the study.
Arm measurements were taken throughout the one-year study. A woman was considered to have lymphedema if her affected arm swelled by 5% or more.
Eleven percent of 72 women in the weight lifting group had their affected arm swell by 5% or more vs. 17% of 75 women who did not change their normal physical activities.
Among women who had five or more lymph nodes removed during breast cancer surgery, 7% of 45 women in this group had arm swelling of 5% or more, compared with 22% of 49 women who did not lift weights. This translates to a 70% reduction in risk, Schmitz says.