The Impact of Axillary Lymph Node Surgery on Breast Skin Thickening During and After Radiation Therapy for Breast Cancer

Abstract

Purpose This prospective study was conducted to determine predictors of epidermal thickening during and after whole breast radiotherapy (XRT) using objective measurements acquired with ultrasound. Methods and Materials Following 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 post XRT, subjects underwent objective ultrasound measurements of epidermal thickness over the lumpectomy cavity and all four 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 of 27%, SD of 0.29) prior to XRT. The STRA increased significantly by week 6 of XRT (mean 25% (SD .46) and continued to increase significantly 6 weeks post XRT (mean 33% (SD .46) above baseline measurements (p<0.001 for both timepoints). In multivariable analysis, breast volume (p=0.003) and surgical evaluation of the axilla with full lymph node dissection (p<0.05) predicted for more severe changes in STRA 6 weeks after XRT compared with baseline. STRA measurements correlated with physician ratings of skin toxicity according to RTOG grading criteria. Conclusions This is one of the first studies to objectively document that lymph node surgery impacts XRT-induced skin thickening in breast cancer patients. Surgical evaluation of the axilla with a complete lymph node dissection was associated with the most severe XRT-induced skin changes following 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.

Full axillary lymph node dissection and increased breast epidermal thickness 1 year after radiation therapy for breast cancer

“…In our initial report, active smoking predicted for worse baseline STRA . While active smoking did not predict for increased STRA at 1 year post‐RT, higher baseline STRA significantly predicted for increased STRA at 1 year.…”

“…In our previous cross-sectional and prospective studies, we found that objective skin thickness measurements using ultrasound images strongly correlate with physician assessments of cutaneous toxicity grading using the Radiation Therapy Oncology Group (RTOG) criteria. 13,14 In our longitudinal study using ultrasound tissue characterization of acute RT-induced changes to the skin, larger breast volume and surgical evaluation of the axilla with full lymph node dissection vs sentinel lymph node biopsy alone were both associated with increased skin thickening 6 weeks after RT. 13 We established that axillary surgery may impact the breast during and shortly after RT.…”

“…13,14 In our longitudinal study using ultrasound tissue characterization of acute RT-induced changes to the skin, larger breast volume and surgical evaluation of the axilla with full lymph node dissection vs sentinel lymph node biopsy alone were both associated with increased skin thickening 6 weeks after RT. 13 We established that axillary surgery may impact the breast during and shortly after RT. The purpose of this study was to report predictors of long-term breast skin thickening 1 year after RT using ultrasound to objectively measure epidermal thickness in an overlapping cohort of breast patients including some women (77%) described in our previous study plus additional patients who agreed to participate and undergo baseline and long-term assessments.…”

“…Normal tissue injury from RT contributes to persistent breast edema, but our data also indicates that axillary dissection surgery leads to increased breast skin thickening before RT as well as long after RT is complete. We previously reported the early results of our prospective, longitudinal study, which determined that full lymph node dissection impacts breast skin thickness during and up to 6 weeks post‐RT. The current study, which now includes 1 year follow up, documents the persistent effect of axillary surgery on the breast in BCS patients treated with whole breast RT.…”

“…We established that axillary surgery may impact the breast during and shortly after RT. The purpose of this study was to report predictors of long‐term breast skin thickening 1 year after RT using ultrasound to objectively measure epidermal thickness in an overlapping cohort of breast patients including some women (77%) described in our previous study plus additional patients who agreed to participate and undergo baseline and long‐term assessments . Based on our previous findings, we hypothesized that a full axillary lymph node dissection would put patients at risk for more severe changes in breast skin thickening 1 year after RT.…”