BACKGROUND & OBJECTIVE: In Europe and America, breast cancer commonly occurs in women of middle and old age, the median age of patients is about 57 years old. Modified radical mastectomy has taken the place of traditional radical mastectomy, and is called standard radical mastectomy. Patients with breast cancer of early stage commonly receive breast conservative therapy. TNM stage (especially the lymph node status) affects the prognosis, and adjuvant therapy can improve the survival. In China, just a few clinical researches of large amounts of breast cancer patients have been reported. This study was to analyze clinical feature, surgical patterns, treatment outcome of resectable breast cancer, and explore prognostic factors and the effect of adjuvant therapy, for the sake of improving the levels of diagnosis and treatment. METHODS: Records of 6 263 patients with resectable breast cancer, admitted in our hospital from Jun. 1963 to Jun. 2003, were analyzed retrospectively. RESULTS: Of the 6 263 patients, 98.8% were women. Breast cancer occurred most frequently in patients of 40-49 years old (41.0%), especially in patients of 45-49 years old (25.2%). Breast lump was the main clinical manifestation, and occurred in 96.2% of the patients. The 5-, and 10-year survival rates of all patients were 75.2%, and 40.4%. Of the patients in TNM stages 0-I,II, and III, the 5-year survival rates were 96.8%, 73.7%, and 46.4%, respectively the 10-year survival rates were 78.7%, 64.6%, and 33.5%, respectively. The 5-, and 10-year survival rates were higher in lymph node negative group than in lymph node positive group (80.3% vs. 55.6%, and 59.2% vs. 31.9%, P<0.01). There was no significant difference in survival rates of patients received radical mastectomy and modified radical mastectomy since 1980's (P>0.05). Of the 73 patients received breast conservative therapy, no local recurrence or metastasis occurred, with the maximal follow-up of 17 years. Of the patients in stage T2 -T4, the 5-, and 10-year survival rates were significantly higher in adjuvant chemotherapy group than in non-chemotherapy group (78.2% vs. 60.1%, and 48.9% vs. 30.7%, P<0.01). CONCLUSIONS: According to our data, breast cancer most frequently occurred in patients of 45-49 years old. TNM stage (especially the axillary lymph node status)relates to prognosis of breast cancer. The prognosis was worse in the patients with positive lymph node than in the patients with negative Lymph node. The efficacy of modified radical mastectomy equals to that of radical mastectomy, breast conservative therapy can be applied to patients in early stage. Adjuvant chemotherapy and endocrine therapy can improve the survival of resectable breast cancer patients.