Presenter(s)
I. Lasko1, L. Hasnain2, L. C. Saetern2, K. Gomez2, T. Gupte3, H. Kang2, J. Weiss4, P. Bhakta3, K. Ganesh5, C. Reyna3, W. Small Jr1, and T. Refaat1; 1Department of Radiation Oncology, Stritch School of Medicine, Cardinal Bernardin Cancer Center, Loyola University Chicago, Maywood, IL, 2Department of Radiation Oncology, Stritch School of Medicine, Loyola University Chicago, Maywood, IL, 3Department of Surgery, Stritch School of Medicine, Loyola University Chicago, Maywood, IL, 4Department of Hematology and Oncology, Stritch School of Medicine, Loyola University Chicago, Maywood, IL, 5Department of Radiology, Stritch School of Medicine, Loyola University Chicago, Maywood, IL
Purpose/Objective(s): Breast lymphedema (BL) is a complication after breast-conserving therapy (BCT) in breast cancer.(1) There is a paucity of data on the risk factors and diagnostic criteria for BL.(2) The purpose of this study was to assess which factors predict for clinical BL, and whether changes in mammographic skin thickness can be used to detect BL.
Materials/Methods: This IRB-approved study analyzed consecutive patients who underwent BCT with whole breast radiation (WBRT) at our institution. The following data were collected: patient and tumor characteristics, all treatments administered, dosimetry to breast and breast skin, skin thickness on baseline and subsequent mammography (collected from MLO mammograms at the most anterior and inferior points of the breast), and incidence of BL (diagnosed based on symptomatology and clinical exam). Univariable and multivariable logistic regression with likelihood ratio tests, linear mixed-effects model (LMM), and Receiver-Operator Characteristic (ROC) analysis were performed.
Results: 116 patients were included, median age 63 (range 36-86) and mean BMI of 29.7, of whom 24.1% (n=28) developed clinical BL. Median stage was T1cN0, with median (IQR) tumor size 1.6 cm (1.1-2.8). 16.4% (n=19) were node positive. 78% (n=90) had sentinel lymph node biopsy and 4.3% (n=5) had axillary dissection. 35% (n=41) had surgery with oncoplastic technique. 81% (n=94) had lumpectomy bed boost with median total dose of 52.56 Gy (range 26-66) in 21 fractions (range 5-33). 19% (22) had regional nodal irradiation (RNI). On multivariable logistic regression, skin V40 >90 cc (OR 3.91, p=0.026) and increasing age (OR 1.05/year, p=0.032) were independently predictive of BL, while fractionation (conventional vs hypofractionated vs ultrahypofractionated, p=0.10), RNI (OR 1.09, p=0.15), and axillary surgery (dissection vs. sentinel biopsy vs. none, p=0.16) were not. Mammographic skin thickness over time was significantly different between the treated vs contralateral breast in patients with vs without BL (LMM, p=1.29×10?6). On ROC analysis, ? in mammographic skin thickness from baseline to 6-months post-op had AUC of 0.778 (95% CI: 0.686-0.869; optimal cutoff 0.85 mm: 93% sensitivity and 62% specificity) for the detection of BL.
Conclusion: Skin V40 Gy greater than 90cc and older age are independent predictors for breast lymphedema. Mammographic skin thickness can be used as an objective diagnostic criterion for breast lymphedema.
References:- Young-Afat DA, Gregorowitsch ML, van den Bongard DH, et al. Breast Edema Following Breast-Conserving Surgery and Radiotherapy: Patient-Reported Prevalence, Determinants, and Effect on Health-Related Quality of Life. JNCI Cancer Spectr. 2019;3:pkz011.
- Abouelazayem M, Elkorety M, Monib S. P28 Breast Lymphedema after breast conservative surgery; an up-to-date systematic review. BJS Open. 2021;5:zrab032.027.