Assessment of radiation dermatitis using objective analysis for patients with breast cancer treated with breast-conserving therapy: influence of body weight

To evaluate the effect of patient factors on radiation dermatitis for patients with breast cancer who underwent postoperative radiotherapy after breast-conserving surgery. The study population comprised 87 patients who underwent breast-conserving surgery followed by 50 Gy/25 fractions (median) of radiotherapy with or without boost radiation (10 Gy/5 fractions). We examined their treated and contralateral breast skin color by use of an objective analyzer, and expressed findings as L*, a*, b* ratios by dividing by pre-RT values. Next, we examined correlation between patient factors (age, height, body weight, and body mass index, BMI) and change of L* and a* values by use of correlation coefficients. Radiation therapy caused changes in a* and L* ratios (p < 0.0001) but not in b* ratio. The a* ratio (reddish) increased 1.4-fold and peaked after radiotherapy. The L* ratio (darkening) decreased by 10 % and reached a minimum value between completion of radiotherapy and 1 month after treatment. Although, age and height did not affect Delta value, body weight and BMI correlated significantly with Delta a* value (p = 0.0012 and 0.0017) not with Delta L* value. Body weight and BMI predict degree of radiation dermatitis, and more reddish dermatitis was observed for heavier patients than for their lighter counterparts.