The mean dose to whole breast(p = 0.002), the presence of either mut/het XRCC1Arg194Trp or wt XRCC3Thr241Met (p = 0.006) and the presence of either mut/het XRCC1Arg194Trp or wt GSTA1(p = 0.031) were confirmed as predictors of radiotherapy-induced erythema by MVA. This evidence concerns the gene GSTA1 and Erythema.