Late skin and subcutaneous soft tissue changes after 10-Gy boost for breast conserving therapy

Purpose To evaluate the influence of boost irradiation for breast conserving therapy on skin and subcutaneous tissue. Materials and Methods Between 1989 and 1995, 468 patients were treated with breast conserving surgery (quadrantectomy or wide excision with axillary dissection) followed by 50 Gy whole breast irradiation. Among them, fifty-eight patients with positive or close margins were treated with 10 Gy external beam boost irradiation. Skin and subcutaneous soft tissue changes during 5-years of follow-up were examined by inspection and palpation and evaluated using the BCT follow-up form based on EORTC late effect toxicity scoring. Result Four percent (20/468) of the patients showed grade 2 late changes in skin and soft tissue. Four of them had skin telangiectasis, which was limited to within the boost field. Boost irradiation had no definite influence on other late changes. Patients’ age, extent of surgery, and pT size had no significant relation to the late changes. The cosmetic score 5 years after BCT was not significantly different between the patients with and without boost irradiation. Conclusion Although 10 Gy boost irradioation after 50 Gy whole breast irradiation increased skin telangiectasis, the late skin and soft tissue changes caused by the boost irradiation were generally mild and there was no substantial deterioration of cosmetic outcome.