Arm lymphedema is a feared and presently incurable complication of breast cancer surgery and radiation treatment (RT). Lymphedema results from excess interstitial fluid accumulation, which leads to limb swelling and eventual tissue fibrosis that can cause lifelong impairment of arm use. Lymphedema concerns take center stage at many, if not the majority, of preoperative and postoperative consultations with patients who are undergoing breast cancer surgery, given that this complication can permanently harm quality of life, from both a physical/functional perspective as well as a psychosocial one. Findings from a 2013 systematic review and meta-analysis of 72 studies revealed an estimated 17% risk of arm lymphedema among patients with breast cancer, with risk increasing up to 2 years after surgery. The risk was four times higher in women who had a complete axillary lymph node dissection (ALND; 20%) versus those who had sentinel lymph node biopsy alone (5.6%). Among women who receive adjuvant RT after ALND, lymphedema risk is significantly higher. In a 2001 systematic review, the rate of lymphedema among women who underwent surgery plus axillary RT was an alarming 41%. Aside from treatment-related risk factors, a number of patient or disease-related risk factors exist for the development of lymphedema. Postoperative infection or delayed wound healing is associated with heightened lymphedema risk. A much more prevalent risk factor is obesity (body mass index 30 kg/m), which portends a nearly three-fold increase in risk for lymphedema. According to 2009/2010 Centers for Disease Control and Prevention statistics, 36% of all women and 42% of women age 60 years or older are obese in the United States. In the current era, with widening adoption of the findings of the American College of Surgeons Oncology Group (ACOSOG) Z0011 trial, incidence of lymphedema should decline, given that we see decreasing rates of completion ALND among a subset of women undergoing breast-conserving therapy. However, there remains a large population of patients with node-positive disease for whom ALND is still indicated, including those with clinically positive nodes, locally advanced disease, those receiving neoadjuvant chemotherapy, and those undergoing mastectomy. Hence, research into the treatment of this chronic condition remains an important public health issue. Because many lymphedema risk factors are not modifiable, attention has largely been directed at treatment. To this aim, a number of studies have compared efficacy of various treatment options for lymphedema. Treatment options include, alone or in combination, exercise, skin care, compression bandaging, compression garments, manual therapy (massage), laser therapy, and pneumatic pumps. Complex decongestive therapy (CDT) incorporates manual lymphatic drainage, daily bandaging, exercise, and skin care. A systematic review of these therapies was published in 2006 and found that, in general, more intensive treatment by health professionals, such as CDT or manual lymphatic drainage, produced larger volume reductions than therapies undertaken by the patient, such as compression bandaging, exercise, or skin care. Studies of CDT showed an estimated 43% reduction in arm volume compared with only 11% with compression alone. However, excitement over CDT has been tempered by subsequent randomized trials that have thus far failed to demonstrate a significant benefit of CDT over standard compression therapy. In one trial by McNeely et al, 50 women were randomly assigned to 4 weeks of CDT or compression alone. Arm volume decreased significantly with both treatments, but no difference was observed between groups (46% CDT v 39% compression alone; P .22). This study was limited in follow-up to 1 month and did not assess quality-of-life parameters associated with treatment of lymphedema. Another trial by Andersen et al randomly assigned 42 women with lymphedema to CDT versus compression, and observed patients for 12 months. They also found no significant difference in arm volume reduction over the 12-month period between CDT and compression groups (48% v 60%, respectively; P .66). Armed with these data, one might question why yet another randomized controlled trial was necessary to examine this question. Limitations of the above trials included their small size, singleinstitution setting (and sometimes, even single CDT provider), and lack of long-term follow-up. In the article that accompanies this editorial, Dayes et al address all of these limitations in their eloquently designed, randomized, multicenter trial of CDT versus compression bandaging alone for patients with lymphedema. Dayes et al randomly assigned 103 women from six Canadian cancer centers to either CDT or compression bandaging between 2003 and 2009. Type and duration of CDT were standardized across groups, as were arm measurement techniques. Diary logs were JOURNAL OF CLINICAL ONCOLOGY E D I T O R I A L VOLUME 31 NUMBER 30 OCTOBER 2