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BACKGROUND AND OBJECTIVES: The objectives of this study were to confirm the favorable outcome of Japanese invasive breast cancer patients without lymph node metastasis, after treatment with surgery alone, and to evaluate clinicopathological prognostic factors in this population. METHODS: The subjects were 763 consecutive node-negative invasive breast cancer patients who underwent surgery without adjuvant therapies between 1988 and 1993 at our hospital. Disease-free survival (DFS) and overall survival (OS) rates were analyzed by clinicopathological factors. RESULTS: The median age of the patients at surgery was 52 years and the median follow-up period of patients was 74 months. At 5 years, the respective DFS and OS rates of all patients were 90.8% and 93.9%. Patients with a pathological tumor size of invasive component of more than 2 cm (319 patients) had a significantly lower DFS than those with tumors measuring 2 cm or less (361 patients) (P = 0.045). Patients with positive hormone receptor status (280 patients) (estrogen and/or progesterone receptor positive) tended to have a better OS than those negative for both hormone receptors (92 patients) (P = 0.078). Meanwhile, patients with tumors of histological grade 3 (328 patients) had a much poorer prognosis than those with tumors of histological grade 1 or 2 (413 patients) (P = 0.008 for OS and P = 0.042 for DFS). The respective 5-year DFS and OS rates of patients with histological grade 3 tumors larger than 2 cm in pathological tumor size of invasive component (195 patients) were 85.5% and 87.6%, indicating that these node-negative patients form a high risk group. CONCLUSIONS: Japanese invasive breast cancer patients without lymph node metastasis tended to show a survival advantage compared with their Caucasian counterparts. Histological grade was the most useful prognostic factor in this population.
Saimura et al. (Tue,) studied this question.