Dose-surface analysis for prediction of severe acute radio-induced skin toxicity in @entity0 XXXX .

@entity1 @entity1569 @entity0 @entity272
BACKGROUND: Severe acute @entity272 ( @entity272 ) after breast irradiation is a side effect impacting the quality of life in @entity0 ( @entity0 ) @entity1 . The aim of the present study was to develop normal tissue complication probability (NTCP) models of severe acute @entity272 in @entity0 @entity1 . @entity1 AND METHODS: We evaluated 140 consecutive @entity0 @entity1 undergoing conventional three-dimensional conformal radiotherapy (3D-CRT) after breast conserving surgery in a prospective study assessing acute @entity272 . The acute @entity272 was classified according to the RTOG scoring system. Dose-surface histograms (DSHs) of the body structure in the breast region were extracted as representative of skin irradiation. @entity1 , disease, and treatment-related characteristics were analyzed along with DSHs. NTCP modeling by Lyman-Kutcher-Burman (LKB) and by multivariate logistic regression using bootstrap resampling techniques was performed. Models were evaluated by Spearman's Rs coefficient and ROC area. RESULTS: By the end of radiotherapy, 139 (99%) @entity1 developed any degree of acute @entity272 . G3 @entity272 was found in 11 of 140 (8%) @entity1 . Mild-moderate (G1-G2) @entity272 was still present at 40 days after treatment in six (4%) @entity1 . Using DSHs for LKB modeling of acute @entity272 severity (RTOG G3 vs. G0-2), parameter estimates were TD50=39 Gy, n=0.38 and m=0.14 [Rs   =   0.25, area under the curve (AUC)   =   0.77, p   =   0.003]. On multivariate analysis, the most predictive model of acute @entity272 severity was a two-variable model including the skin receiving   >= 30 Gy (S30) and @entity1569 [Rs   =   0.32, AUC   =   0.84, p   <   0.001]. CONCLUSIONS: Using body DSH as representative of skin dose, the LKB n parameter was consistent with a surface effect for the skin. A good prediction performance was obtained using a data-driven multivariate model including S30 and a pre-existing @entity272 ( @entity1569 ) as a clinical factor.
