Prognosis in stage II (T1N1M0) breast cancer.

As part of a detailed study of prognostic factors in breast cancer, we have analyzed the ten year survival rates of 524 patients with primary invasive carcinomas 2.0 cm or less in diameter (T1). This report describes the subset of 142 patients (27%) who had metastases only in axillary lymph nodes (T1N1M0). All the patients were treated initially by at least a modified radical mastectomy. Factors associated with a significantly poorer prognosis were: axillary lymph node metastases suspected on clinical examination; perimenopausal menstrual status at diagnosis; tumor larger than 1.0 cm; prominent lymphoid reaction; infiltrating duct or lobular rather than medullary, colloid and tubular carcinoma; and blood vessel invasion. When compared with those patients with negative nodes (T1N0M0), the patients with one or more lymph node metastases had a significantly poorer prognosis. Generally, survival rates tended to diminish as the number of involved lymph nodes increased. In this respect, comparison of patients with one-three and four or more nodal metastases provided a significant discrimination of prognostic groups in the entire series. However, for patients with disease limited to Level I, the same discrimination was obtained comparing those with one-two and three or more positive nodes. In the subset with a single lymph node metastasis, the size of the metastasis (micro or less than or equal to 2 mm vs macro or greater than 2 mm) was not significantly related to prognosis. Lymph node metastases were significantly less frequent among tumors smaller than 1 cm and special tumor types (medullary, colloid, lobular and tubular). However, no factor proved to be a reliable predictor of the presence of axillary metastases for the single largest group consisting of patients with infiltrating duct carcinoma 1-2 cm in diameter.