D. A. Cerbon1, A. Desai2, S. Choi1, S. Han3, I. M. Reis4, J. R. Mella-Catinchi5, D. P. Singh5, and C. Takita1; 1Department of Radiation Oncology, University of Miami/Sylvester Comprehensive Cancer Center, Miami, FL, 2DeWitt Daughtry Family Department of Surgery, University of Miami/Sylvester Cancer Center, Miami, FL, 3Biostatistics and Bioinformatics Shared Resources, Sylvester Comprehensive Cancer Center, University of Miami Miller School of Medicine, Miami, FL, 4Department of Public Health Sciences and Sylvester Biostatistics/Bioinformatics Shared Resources (BBSR), University of Miami, Sylvester Comprehensive Cancer Center, Miami, FL, 5DeWitt Daughtry Family Department of Surgery, Division of Plastic and Reconstructive Surgery, University of Miami, Miami, FL
Purpose/Objective(s): Incidence of breast cancer-related lymphedema (BCRL) ranges from 15-40% after axillary node dissection (ALND) depending on treatments like comprehensive nodal irradiation (RNI). Bioimpedance spectroscopy (BIS) generates an L-Dex Score and is an objective measure of BCRL with ability to detect subclinical lymphedema (SLE). ALND, neoadjuvant chemotherapy, age, BMI and RNI are known risk factors for BCRL, however, associations with race and ethnicity remain understudied. LYMPHA is a prophylactic surgery done at the time of ALND to reduce the risk of BCRL. Our study aims to assess the incidence of BCRL using BIS, in patients receiving ALND, RNI, and LYMPHA, and identify risk factors for BCRL in this population.Materials/
Methods: A single-institution retrospective study included breast cancer patients undergoing ALND, RNI (axillary, supraclavicular, IMN nodes), and LYMPHA, with a follow-up of at least one year. Using BIS we defined SLE and lymphedema (LE) as L-Dex measurement increase of 6.5-9.9 and =10 units from baseline, respectively. We assessed the extent of axillary RT, doses delivered, demographic, clinical, and treatment variables. Primary outcome was presence of SLE or LE. We performed univariable analysis to identify factors associated with an increase in SLE and LE rates. Results: Between April 2021-June 2022, we identified 54 patients, mean age and BMI were 52.8 years (46 - 59), and 27.7 kg/m² (24.6 - 31.9), respectively. 43 (79.6%) were White, 8 (14.8%) Black, and 3 Asian (5.6%). 18 (33.3%) had Hispanic ethnicity, 1 was Black-Hispanic. 61% had clinical stage III, 40 (74.1%) had Level I&II ALND. Median number of nodes resected was 18 (14-23), 21 (38.9%) having 2-3 positive ALN and 19 (35.2%) having =4. All patients received IMRT or proton (8 pts, 14.8%) to the chestwall/breast (CWB)/RNI. RT doses ranged from 40-42.56 Gy in 15-16 fx (Hypofractionated) in 29 (53.7%) patients, and 45-50.4 Gy in 25-28 fx (standard) in 25 (46.3%) pts. Dissected axilla was fully covered in 46 (85.2%) pts. CWB boost was given in 27 pts, and LN boost in 5, doses ranging 10-16Gy in 4-8fx. Only 18 of 43 patients had L-Dex scores =6.5, 9 (16.7%) SLE and 9 (16.7%) LE. Univariable logistic regression analyses showed age (OR, 4.96; 95% CI, 1.32-18.67; p=0.018), ethnicity (OR, 0.15; 95% CI, 0.04-0.54; p=0.004) and CWB boost (OR, 4.09; 95% CI, 1.19-13.98; p=0.025) were significant predictors for the risk of SCL/LE (P<0.05). Low number of patients who developed SCL/LE (n=18) prohibited estimation controlling for all other risk factors simultaneously in a single multivariable model. Conclusion: Historical data of LE after ALND and RNI show an incidence ranging from 20-40%. Despite the use of ALND and comprehensive RNI in this high-risk group for BCRL, the addition of LYMPHA decreased incidence of LE to 16.7% at a 1 year follow up. Our study showed that age, ethnicity, and chestwall/breast boost were significant risk factors for SLE and LE. Larger studies with longer follow-up are needed to confirm above findings.
