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

ABSTRACT

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.