Preoperative lymphoscintigraphy and tumor histologic grade are associated with surgical detection of the sentinel lymph node.

OBJECTIVE To study which variables involved in the process of selective sentinel node biopsy (SSNB) influence the intraoperative detection of the sentinel lymph node. MATERIAL AND METHODS This was a prospective cross-sectional study in 210 patients (mean age, 54 years) diagnosed with breast cancer who underwent SSNB. We recorded clinical, radiological, radioisotope administration, surgical, and histological data as well as follow-up data. We did a descriptive analysis of the data and an associative analysis using multivariable regression. RESULTS Deep injection alone was the most common route of radioisotope administration (72.7%). Most lesions were palpable (57.1%), presented as nodules (67.1%), measured less than 2 cm in diameter (64.8%), were located in the upper outer quadrant (49.1%), were ductal carcinomas (85.7%), were accompanied by infiltration (66.2%), and had a histologic grade of differentiation of ii (44.8%). Preoperative scintigraphy detected the sentinel node in 97.6% of cases and 95.7% were detected during the operation. One axillary relapse was observed. In the associative study, the variables "preoperative lymphoscintigraphy" and "histologic grade of differentiation of the tumor" were significantly associated with the detection of the sentinel lymph node during the operation. CONCLUSION The probability of not detecting the sentinel lymph node during the surgical intervention is higher in patients with high histologic grade tumors or in patients in whom preoperative lymphoscintigraphy failed to detect the sentinel node.