Patients who have received breast cancer treatment have been told that exercise will not instigate the onset of lymphedema.
There had been some controversy about advising people recovering from the illness to participate in physical activity, but scientists at the University of Missouri analysed medical records and found that the benefits of exercise were more significant than the risks.
Lymphedema is caused by the removal or radiation of lymph nodes in breast cancer treatment and can cause a painful chronic swelling in some patients.
"Breast cancer survivors do not need to restrict their activity as we once thought," said Jane Armer, from the Sinclair School of Nursing at the university.
She explained that patients should choose their physical activities carefully as being active has many health benefits, including possibly reducing the risk of the tumours reoccurring.
According to Cancer Research, it is in the second stage of breast cancer when the disease first affects the lymph nodes.