- The primary tumor within the breast must be palpable and measurable on clinical examination and ultrasound, and must be confined to one breast. For patients with clinically negative axillary nodes, the primary tumor size must be between 2 to 7 cm. For patients with clinically positive axillary nodes, any primary tumor size up to 7 cm is acceptable (T2-3, N0, M0 or T1-3, N1, M0).