Appropriate evaluation of and risk factors for radiation dermatitis in breast cancer patients receiving hypofractionated whole-breast irradiation after breast-conserving surgery.

Background: In grading radiation-induced dermatitis (RID), there are not only inter-evaluator differences but also intra-evaluator variations. We retrospectively analyzed the advantages of establishing a more precise evaluation method using photographs to minimize intra-evaluator variations and RID risk factors.

Methods: We analyzed 301 breasts, including those of 3 patients with bilateral breast cancer who underwent hypofractionated whole-breast irradiation (WBI) after breast-conserving surgery. Four radiation oncologists (A, B, C and D) evaluated photographs taken before, during and after radiation therapy and graded RID using two methods.

Results: The percentages of maximum grades between the two methods varied widely. Kappa statistics revealed that the inter- and intra-evaluator agreements were mostly fair. In multivariate analysis, age (≤60 years old), boost irradiation, concurrent hormonal therapy and chemotherapy prior to WBI are statistically significant risk factors for ≥ grade 2 RID according to two evaluators (B and D), two evaluators (A and B), one evaluator (B) and one evaluator (D), respectively.

Conclusions: The assessment of serial skin change in photographs is useful for judging RID. No risk factor was statistically significant for all evaluators because of wide intra-evaluator variations and large inter-evaluator differences. More objective criteria are needed for appropriate evaluation of RID.