GUIDELINES FOR SENTINEL NODE BIOPSY AND LYMPHATIC MAPPING OF PATIENTSWITH BREAST-CANCER

Objective To define preliminary guidelines for the use of lymphatic ma pping techniques in patients with breast cancer. Summary Background Da ta Lymphatic mapping techniques have the potential of changing the sta ndard of surgical care of patients with breast cancer. Methods Four hu ndred sixty-six consecutive patients with newly diagnosed breast cance r underwent a prospective trial of intraoperative lymphatic mapping us ing a combination of vital blue dye and filtered technetium-labeled su lfur colloid. A sentinel lymph node (SLN) was defined as a blue node a nd/or a hot node with a 10:1 ex vivo gamma probe ratio of SLN to non-S LN. All SLNs were bivalved, step-sectioned, and examined with routine hematoxylin and eosin (H&E) stains and immunohistochemical stains for cytokeratin. A cytokeratin-positive SLN was defined as any SLN with a defined cluster of positive-staining cells that could be confirmed his tologically on H&E sections. Results Fine-needle aspiration (FNA) or s tereotactic core biopsy was used to diagnose 195 of the 422 patients ( 46.2%) with breast cancer; 227 of 422 patients (53.8%) were diagnosed by excisional biopsy. The SLN was successfully identified in 440 of 46 6 patients (94.4%). Failure to identify an SLN to the axilla intraoper atively occurred in 26 of 466 patients (5.6%). In all patients who fai led lymphatic mappings, a complete axillary dissection was performed, and metastatic disease was documented in 4 of 26 (15.4%) of these pati ents. Of the 26 patients who failed lymphatic mapping, 11 of 227 (4.8% ) were diagnosed by excisional biopsy and 15 of 195 (7.7%) were diagno sed by FNA or stereotactic core biopsy. Of interest, there was only on e skip metastasis (defined as a negative SLN with higher nodes in the chain being positive) in a patient with prior excisional biopsy. A mea n of 1.92 SLNs were harvested per patient. Twenty percent of the SLNs removed were positive for metastatic disease In 105 of 440 (23.8%) of the patients. Descriptive information on 844 SLNs was evaluated: 339 o f 844 (40.2%) were hot, 272 of 844 (32.2%) were blue, and 233 of 844 ( 27.6%) were both hot and blue. At least one positive SLN was found in 4 of 87 patients (4.6%) with noninvasive (ductal carcinoma ii, situ) t umors. A greater incidence of positive SLNs was found in patients who had invasive tumors of increasing size: 18 of 112 patients (16%) with tumor size between 0.1 mm and 1 cm had positive SLNs. However, a signi ficantly greater percentage of patients (43 of 131 [32.8%] with tumor size between 1 and 2 cm and 31 of 76 [40.8%] with tumor size between 2 and 5 cm) had positive SLNs. The highest incidence of positive SLNs w as seen with patients of tumor size greater than 5 cm; in this group, 9 of 12 (75%) had a positive SLN (p < 0.001). Conclusions This study d emonstrates that accurate SLN identification was obtained when all blu e and hot lymph nodes were harvested as SLNs; Therefore, lymphatic map ping and SLN biopsy is most effective when a combination of vital blue dye and radio-labeled sulfur colloid is used. Furthermore, these data demonstrate that patients with ductal carcinoma in situ or small tumo rs exhibit a low but significant incidence of metastatic disease to th e axillary lymph nodes and may benefit most from selective lymphadenec tomy, avoiding the unnecessary complications of a complete axillary ly mph node dissection.