Six-year follow-up of patients with microinvasive, T1a, and T1b breast carcinoma.

Abstract

Management of patients with breast cancers < or = 1 cm remains controversial. Reports of infrequent nodal metastases in tumors < or = 5 mm has led to suggestions that axillary dissection should be selective, and that tumor characteristics should guide adjuvant therapy. A retrospective review of 290 patients with breast cancer 1 cm in size or smaller from 1989 to 1991 was done. Distant disease-free survival (DDFS) was the primary outcome measure. There were 95 T1a (< or = 5 mm) and 196 T1b (6-10 mm) cancers. Nodal metastases were found in 8 T1a and 26 T1b tumors. Larger size, poorer differentiation, and lymphovascular invasion (LVI) were associated with more nodal metastases, but none of these trends reached statistical significance. The 6-year DDFS was 93% for node-negative and 87% for node-positive patients (P = .02). Overall, breast cancers with poorer differentiation and LVI trended toward a poorer outcome. For patients with node-negative tumors, LVI was associated with a poorer outcome (P = .03). The size of the primary tumor was not predictive of outcome. There were no nodal metastases or recurrences in the 18 patients with microinvasive breast cancer. Lymph node status is the major determinant of outcome in breast cancers 1 cm in size or smaller. Accurate axillary assessment remains crucial in management of small breast cancer.