A NOVEL, VALIDATED METHOD TO QUANTIFY BREAST CANCER-RELATED LYMPHEDEMA (BCRL) FOLLOWING BILATERAL BREAST SURGERY

We sought to develop a formula to quantify breast cancer-related lymphedema (BCRL) after bilateral breast surgery, which functions independently of the contralateral arm and accounts for fluctuations in patient weight. Perometer arm measurements from 265 unilateral breast surgery patients were analyzed. We assessed the relationship between change in patient weight and contralateral arm volume and developed a weight-adjusted volume change formula (WAG). The WAG formula and previously-established RVC formula were compared for classification of BCRL (>= 10% volume increase) in unilateral breast surgery patients. We then evaluated BCRL incidence using the WAG formula in 225 bilateral mastectomy patients. Change in patient weight and contralateral arm volume demonstrated an approximately linear relationship. Weight-adjusted arm volume change (WAG) was therefore calculated as WAG = (A2*W1) / (W2*A1) - 1 where A1 is pre-operative and A2 is post-operative arm volume, and W1, W2 are the patient's corresponding weights. In the unilateral analysis, there was no significant difference in number of patients classified as having BCRL using the RVC and WAG formulas (p = 0.65). In bilateral mastectomy patients 11.1% (251225) developed BCRL, defined as >= 10% WAG. Independent risk factors for lymphedema included axillary lymph node dissection (ALND) and higher pre-operative BMI (p<0.05). Use of this weight-adjusted arm volume change formula should be of value for quantification of BCRL after bilateral breast surgery.