Among all breast cancer patients, being obese or overweight may predispose women to developing lymphedema after treatment for breast cancer.[11,23][Level of evidence: I] A well-conducted prospective study followed 138 breast cancer patients for 30 months postdiagnosis. Individuals with body mass indices of 30 or higher at the time of diagnosis were 3.6 times more likely to develop lymphedema, but weight gain after diagnosis was not related.
Some studies have correlated the degree of lymphedema with the level of obesity.[Level of evidence: I] Similarly, among young breast cancer survivors, persistent swelling was related to having more lymph nodes removed and being obese.
The dose-response relationship between obesity and risk for lymphedema onset is not known. There have also been no studies to determine whether weight loss among patients at risk for developing lymphedema would reduce risk. At this time, it is not possible to advise patients regarding the dose-response relationship of weight loss and risk reduction or the body weight associated with lowest risk of incident lymphedema.
Other risk factors for developing lymphedema include the following:
- Extent of local surgery.
- Local radiation (axillary, inguinal, pelvic, or supraclavicular regions).
- Delayed wound healing.
- Tumor causing lymphatic obstruction of the anterior cervical, thoracic, axillary, pelvic, or abdominal nodes.
- Scarring of the left or right subclavian lymphatic ducts by either surgery or radiation.
- Intrapelvic or intra-abdominal tumors that involve or directly compress lymphatic vessels and/or the cisterna chyli and thoracic duct.
Roughly one-third of breast cancer patients (and a majority of African Americans with breast cancer) present with regional disease and positive lymph nodes, thus requiring complete axillary lymph node dissection; many undergo further irradiation of their axillary and supraclavicular lymph node beds. Lymphedema is a persistent adverse effect of breast cancer treatment that will continue to occur long into the future, despite increasing use of sentinel lymph node biopsy procedures.
Exercise does not increase risk of lymphedema onset
Historically, those at risk for lymphedema have been advised to avoid using the affected limb. The reasoning for this clinical advice seems to arise from the notion that the removal of lymph nodes altered the response of the affected area to inflammation, infection, injury, and trauma—therefore, it would be wise to avoid stressing the limb. However, exercise has a different effect on the body at lower doses than it does at higher doses; extreme exercise would promote inflammation and injury and should be avoided in patients at risk for lymphedema. By contrast, slowly progressive, carefully controlled increases in physiologic stress on a limb at risk for lymphedema may actually provide protection for real-life situations that require taxing that body part (e.g., carrying grocery bags, doing holiday shopping, or lifting a child). Therefore, physiologic evidence exists to question the historic advice to restrict use of the affected limb.