Sentinel lymph node biopsy in breast cancer: Unfiltered radioisotope is superior to filtered

Background: The combination of gamma-probe radiolocalization and blue-dye m apping of sentinel lymph nodes (SLNs) has been advocated as the most accura te method for staging the clinically negative axilla in breast cancer patie nts, but the technical aspects of these procedures are not fully characteri zed in the literature, In this study, we compared the success of SLN locali zation in 134 consecutive breast cancer patients using blue dye plus two di fferent preparations of radiocolloid. Study Design: A retrospective analysis of a prospectively maintained data b ase was performed to assess SLN localization in two cohorts of patients, Un filtered technetium-99m (Tc-99m) sulfur colloid tin 77 patients; group I) w as compared with filtered Tc-99m sulfur colloid (in 57 patients; group II). All patients had a peritumoral injection of blue dye and isotope, followed immediately by lymphoscintigraphy to confirm radioactivity at the injectio n site and to image the SLN, Statistical analysis was performed using the P earson chi-square test. Results: Unfiltered Tc-99m sulfur colloid was superior to the filtered radi ocolloid in localizing the SLN (88% versus 73%; p = 0.03), SLN imaging by l ymphoscintigraphy was also more successful in the unfiltered group. Using t he combination of blue dye and radiolocalization, SLNs were identified in 9 4% of patients. Conclusions: For optimal localization of the SLN in breast cancer patients, surgeons should use the combined technique of blue-dye mapping and gamma-p robe localization using unfiltered Tc-99m sulfur colloid. (J Am Cell Surg 1 999;188:377-381, (C) 1999 by the American College of Surgeons).