Effects of superoxide dismutase topical treatment on human skin radiofibrosis: a pathological study

S U M MA R Y. Fourty-two patients, presenting with clinically evaluable cutaneous fibrosis after radiotherapy for breast carcinoma, were treated for 3 months by a superoxide dismutase (SOD) topical preparation. Sequential cutaneous punch biopsies were performed before and 3 months after completion of the treatment. The histochemical grading, using an objective spectrometric method, showed a decrease of fibrosis in 74% of treated patients. The immunohistochemical expression of smooth muscle cells (SMC) a-actin, epidermal growth factor-receptor (EGFR) and transforming growth factor pl (TGFPl) was studied. SOD treatment resulted in an increase of SMC a-actin expressing fibroblasts in 79% and an increase of EGFR expressing epidermal cells in 67% cases. It did not modify the expression of TGFPl . In conclusion, topical SOD appeared to reduce collagen accumulation in the dermis of irradiated skin and to ‘reactivate’ cellular functions in dermal fibroblasts and epidermal cells, as demonstrated by phenotypic changes.