International comparison of cosmetic outcomes of breast conserving surgery and radiation therapy for women with ductal carcinoma in situ of the breast.

Abstract

PURPOSE\nTo assess the cosmetic impact of breast conserving surgery (BCS), whole breast irradiation (WBI) fractionation and tumour bed boost (TBB) use in a phase III trial for women with ductal carcinoma in situ (DCIS) of the breast.\n\n\nMATERIALS AND METHODS\nBaseline and 3-year cosmesis were assessed using the European Organization for Research and Treatment of Cancer (EORTC) Cosmetic Rating System and digital images in a randomised trial of non-low risk DCIS treated with postoperative WBI +/- TBB. Baseline cosmesis was assessed for four geographic clusters of treating centres. Cosmetic failure was a global score of fair or poor. Cosmetic deterioration was a score change from excellent or good at baseline to fair or poor at three years. Odds ratios for cosmetic deterioration by WBI dose-fractionation and TBB use were calculated for both scoring systems.\n\n\nRESULTS\n1608 women were enrolled from 11 countries between 2007 and 2014. 85-90% had excellent or good baseline cosmesis independent of geography or assessment method. TBB (16\u202fGy in 8 fractions) was associated with a >2-fold risk of cosmetic deterioration (p\u202f<\u202f0.001). Hypofractionated WBI (42.5\u202fGy in 16 fractions) achieved statistically similar 3-year cosmesis compared to conventional WBI (50\u202fGy in 25 fractions) (p\u202f≥\u202f0.18). The adverse impact of a TBB was not significantly associated with WBI fractionation (interaction p\u202f≥\u202f0.30).\n\n\nCONCLUSIONS\nCosmetic failure from BCS was similar across international jurisdictions. A TBB of 16\u202fGy increased the rate of cosmetic deterioration. Hypofractionated WBI achieved similar 3-year cosmesis as conventional WBI in women treated with BCS for DCIS.