Purpose: Sentinel-node biopsy is becoming widely accepted in breast cancer treatment. Using the radioisotope technique, a lower risk of identification failure is related to the amount of radiocolloid in the sentinel nodes. The aim of this study was to identify the factors associated with the colloidal uptake of the sentinel nodes.
Methods: Technetium-labeled colloid was injected peritumorally, with or without subdermal injection. According to the maximum radioactivity of the sentinel nodes, patients were divided into high (>/=100 counts/s) or low (<100 counts/s) uptake groups. The uptake was compared in relation to the clinicopathologic and technical features.
Results: The sentinel node was identified in 183 of 186 patients (98.4%), with 60 and 123 patients in the low- and high-uptake groups (mean: 39 and 1003 counts/s), respectively. Multivariate analysis showed that an age of 65 years or older and a sentinel-node size of 8 mm or more were significantly more predominant in the low-uptake group.
Conclusion: Care must be taken when performing sentinel-node biopsy, especially for aged patients and for those with large sentinel nodes. The optimal technique should be determined on the basis of these results.