There is no consistency in the data on the incidence and prevalence of lymphedema after breast cancer, probably because of differences in diagnosis, the different characteristics of the patients studied, and inadequate follow-up to capture delayed development of the disorder. The overall incidence of arm lymphedema can range from 8% to 56% at 2 years postsurgery.
It is important to diagnose and treat lymphedema when it is mild because those with mild lymphedema make up the cohort that gives rise to preventable severe, debilitating lymphedema. Women with mild lymphedema are more than three times as likely to develop severe lymphedema than are women with no lymphedema.
Patients undergoing axillary surgery and/or axillary radiation therapy for breast cancer are at higher risk for developing lymphedema of the arm. Previous convention suggested that nodal positivity was a predisposing factor for the development of lymphedema in breast cancer patients. Controlling for axillary radiation, one study actually found an inverse relationship between nodal positivity and arm volume.
Axillary node removal
Compared with axillary sampling alone, partial or total mastectomy followed by full axillary lymph node dissection significantly increases a patient's chance of developing arm edema. For example, in one series of 100 women who underwent partial or total mastectomy and then full axillary lymph node dissection or axillary sampling, arm edema developed in more patients who underwent axillary lymph node dissection compared with sampling alone (30% vs. none). In addition, the extent of axillary lymph node dissection increases the risk for developing arm edema. For example, in one series involving 381 women undergoing segmental mastectomy and axillary lymph node dissection, women who had ten or more lymph nodes removed were more likely than women who had few lymph nodes in the specimen to develop arm symptoms within the first year (53% vs. 33%) and within the next 2 years (33% vs. 20%).
Sentinel node biopsy
For patients with breast cancer, sentinel lymph node dissection has gained favor over axillary lymph node dissection for the axillary staging of early disease because of decreased morbidity and because of the questionable survival benefits of axillary lymph node dissection, as shown in a phase III randomized study (ACOSOG-Z0011) of axillary lymph node dissection in women who had stage I or IIA breast cancer and a positive sentinel node.[Level of evidence: I] Several studies have shown that lymphedema is more prevalent in breast cancer patients who undergo axillary lymph node dissection than in those who undergo sentinel lymph node biopsy.[Level of evidence: II] One study evaluated 30 patients with unilateral invasive breast carcinoma who underwent sentinel lymph node biopsy and 30 patients who underwent axillary lymph node dissection. This study found a 20% rate of developing lymphedema in the axillary lymph node dissection group compared with none in the sentinel lymph node biopsy group. Rates of lymphedema among women who undergo sentinel lymph node biopsy have been reported to be between 5% and 17%, depending on the diagnostic threshold and length of follow-up.[20,21,22] The majority of diagnosed lymphedema is mild.[Level of evidence: II]