Objective Assessment of Dermatitis Following Post-operative Radiotherapy in Patients with Breast Cancer Treated with Breast-conserving Treatment

To evaluate radiation dermatitis objectively in patients with breast cancer who had undergone post-operative radiotherapy after breast-conserving surgery. Skin color (L*, a*, and b* values) and moisture analyses were performed for both breasts (before, after, 1 month, 6 months, and 1 year after radiotherapy) to examine irradiated and non-irradiated skin divided into four quadrants in 118 patients. These patients underwent breast conservative surgery followed by 50 Gy/25 fractions (median) of radiotherapy with or without boost irradiation (10 Gy/5 fractions). L*, a*, and moisture values were changed by irradiation and maximized at completion or 1 month after radiotherapy. One year after radiotherapy, the skin color had returned to the range observed prior to radiotherapy. However, moisture did not return to previous values even 1 year after treatment. The lateral upper side (quadrant C) showed greater changes than other quadrants in the L* value (darker) at the end of radiotherapy. The Common Toxicity Criteria version 3 scores were found to correlate well with a* and L* values at the completion and 1 month after radiotherapy. Boost radiotherapy intensified reddish and darker color changes at the completion of radiotherapy, while chemotherapy did not intensify the skin reaction caused by radiotherapy. Moisture impairment as a result of irradiation lasts longer than color alterations. Objective assessments are useful for analyzing radiation dermatitis.