Most of the reported experience with SLN biopsy includes patients with clinical stage T1-2N0 invasive breast cancers. SLN biopsy has an emerging role in microinvasive breast cancers and in selected cases of duct carcinoma in situ [in-situ ductal carcinoma], particularly those with a high risk of occult invasion (evidenced by a palpable mass or extensive disease requiring mastectomy).