DISEASE CHARACTERISTICS: Histologically proven adenocarcinoma of the breast No apocrine, adenoidcystic, or squamous carcinomas or sarcomas Pathologic Stage T1-3a, pathologic N1-2 (clinical N0-1), M0: Rendered free of gross tumor at surgery Primary tumor movable with respect to chest wall Axillary nodes movable with respect to chest wall and each other No preoperative edema of the arm, peau d'orange, skin ulceration, or inflammatory lesions One or more positive lymph nodes required No positive deep mastectomy margins or clinical skin involvement (focal microscopic dermal invasion or focal microscopic dermal lymphatic involvement allowed) No evidence of metastatic disease on pretherapy studies (including chest x-ray, bone scan, and mammogram) No bilateral invasive tumors Patients who had noninvasive ductal carcinoma in situ of the opposite breast and underwent prophylactic contralateral mastectomy are eligible Hormone receptor status: Positive for estrogen and/or progesterone receptors (at least 10 fmol/mg protein or unequivocally positive immunocytochemical assay for one or both) Participation in SWOG-8854 (flow cytometry) recommended