Axillary dissection after unsuccessful sentinel lymphadenectomy for breast cancer.

Intraoperative lymphatic mapping and sentinel lymphadenectomy (LM/SL) has been demonstrated to provide sensitive axillary staging for breast cancer. LM/SL has a steep learning curve, and factors associated with unsuccessful LM/SL are not well known. Two hundred sixty patients with breast carcinoma and clinically negative axillae underwent injection of about 5 cm3 of isosulfan blue dye (Lymphazurin, US Surgical Corp, Norwalk, CT) into breast tissue surrounding a cancer or biopsy site. After 5 minutes of breast compression, blue-stained lymph nodes were sought. In 47 patients, no blue nodes were detected; a standard axillary dissection was performed. All 47 patients were women with a mean age of 56 years (range, 34-80). Ductal carcinoma was most common (91.5%). Mean tumor size was 1.99 cm. Axillary dissection yielded a mean of 15.8 lymph nodes (range, 6-35). Sixteen patients (34%) had positive lymph nodes (mean, 7.6; median, 6; range, 1-24). Factors associated with LM/SL difficulty include surgeon inexperience, medial hemisphere primary location, extensive axillary metastases, and extranodal invasion. Inability to identify a sentinel node in a clinically negative axilla is a risk factor for extensive axillary tumor burden. Axillary dissection should be performed for patients with unsuccessful LM/SL, particularly those with lateral hemisphere primaries.