THE EFFECTS OF POSTRADIATION TREATMENT WITH TAMOXIFEN ON LOCAL-CONTROL AND COSMETIC OUTCOME IN THE CONSERVATIVELY TREATED BREAST

BACKGROUND. The aim of this study was to evaluate the impact on diseas e recurrence and cosmetic outcome of tamoxifen treatment initiated aft er breast-conserving therapy (BCT). METHODS. Between 1982 and 1994, 49 8 women (509 breasts) were treated with BCT in accordance with a highl y standardized institutional protocol. Adjuvant tamoxifen was administ ered to 130 patients (134 breasts), beginning 1-6 weeks after irradiat ion. The median ages and duration of follow-up for groups who received tamoxifen (TAM+) and no tamoxifen (TAM-) were 62.5 years/56 months an d 53 years/60 months, respectively. The members of the TAM+ group were significantly older (P = 0.0001) and had increased incidences of posi tive axillary lymph nodes or undissected axilla (P = 0.001). There was a significant (P = 0.001) difference between the TAM+ and TAM- groups in the distribution of histopathologic subtypes; this reflected an in creased proportion of associated ductal carcinoma in situ in the TAM- group. More extensive regional lymphatic irradiation was administered to the TAM+ group. Chemotherapy was administered to 15% of TAM+ and 28 % (P = 0.003) of TAM- patients. There were no significant differences between the groups with respect to tumor size, reexcision, total excis ed tissue volume, final margin status, total radiation dose, or use of interstitial implant boost. RESULTS. There was no significant differe nce between the TAM+ and TAM-groups in the overall distribution of cos metic scores (P = 0.18). The 5-, 7-, and l0-year actuarial local failu re rates for TAM+ versus TAM- patients were O% versus 3.1%, 1.9% versu s 5.4%, and 1.9% versus 8.4%, respectively. Multivariate regression an alyses of potentially confounding variables revealed no significant as sociations between tamoxifen and either cosmetic outcome or local fail ure. CONCLUSIONS. Radiotherapy followed by tamoxifen has no adverse in teractive effect on cosmesis, and tamoxifen is associated with a trend toward enhanced 5-year local control probability. (C) 1997 American C ancer Society.