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Background: We previously reported a prospective study showing axillary lymph node dissection (ALND) is associated with increased breast skin thickening during and 6 weeks post-radiation therapy (RT), and now report ALND's long-term impact at 1 year., Methods: Among 66 women who received whole breast RT after lumpectomy, objective ultrasound measurements of epidermal thickness over four quadrants of the treated breast were measured at five time points: before RT, week 6 of RT, and 6 weeks, 6 months, and 1 year post-RT. Skin thickness ratio (STRA) was generated by normalizing for corresponding measurements of the contralateral breast., Results: A total of 2,436 ultrasound images were obtained. Among 63 women with evaluable data at 1 year, mean STRA significantly increased at 6 months (absolute mean increase of 65%, SD 0.054), and remained elevated at 1 year post-RT (absolute mean increase of 44%, SD 0.048). In multivariable analysis, ALND compared to sentinel lymph node biopsy, longer interval between surgery and RT, increased baseline STRA, and Caucasian race predicted for more severe changes in STRA at 1 year compared to baseline (all P < .05)., Conclusions: In the setting of whole breast RT, our findings suggest that ALND has long-term repercussions on breast skin thickening., (© 2019 Wiley Periodicals, Inc.)

Purpose: This prospective study was conducted to determine predictors of epidermal thickening during and after whole-breast radiation therapy (XRT) using objective measurements acquired with ultrasound.Methods and Materials: After breast-conserving surgery, 70 women received a definitive course of whole-breast XRT (50 Gy plus boost). Prior to XRT, at week 6 of XRT, and 6 weeks after XRT, patients underwent objective ultrasound measurements of epidermal thickness over the lumpectomy cavity and all 4 quadrants of the treated breast. A skin thickness ratio (STRA) was then generated normalizing for corresponding measurements taken of the untreated breast.Results: Baseline measurements indicated that 87% of patients had skin thickening in the treated versus untreated breast (mean increase, 27%; SD, 0.29) prior to XRT. The STRA increased significantly by week 6 of XRT (mean, 25%; SD, 0.46) and continued to increase significantly 6 weeks after XRT (mean, 33%; SD, 0.46) above baseline measurements (P<.001 for both time points). On multivariate analysis, breast volume (P=.003) and surgical evaluation of the axilla with full lymph node dissection (P<.05) predicted for more severe changes in the STRA 6 weeks after XRT compared with baseline. STRA measurements correlated with physician ratings of skin toxicity according to Radiation Therapy Oncology Group grading criteria.Conclusions: This is one of the first studies to objectively document that lymph node surgery affects XRT-induced skin thickening in patients with breast cancer. Surgical evaluation of the axilla with complete lymph node dissection was associated with the most severe XRT-induced skin changes after XRT completion. These results may inform future studies aimed at minimizing side effects of XRT and surgery, particularly when surgical lymph node assessments may not alter breast cancer management or outcome. [ABSTRACT FROM AUTHOR]