Abstract
BACKGROUND: Intensified examination of the sentinel lymph node (SN) may result in increased detection of tumor-affected lymph nodes. The authors of this report hypothesized that the introduction of the SN procedure has led to stage migration because of the intensified workup of SNs by pathologists. METHODS: After the introduction of the SN procedure, 360 patients with operable breast cancer were included prospectively from 2 large hospitals (Hospital A and Hospital B). The prospectively included patients (the "SN era" group) were compared with 88 historic controls from the year 1994 who were diagnosed with primary breast cancer before introduction of the SN procedure. RESULTS: After correcting for classic clinical and pathologic prognostic factors in a multiple logistic regression analysis, the detection frequency of lymph node involvement was significantly higher in the SN era group compared with historic controls (P = .04). However, when using the 2002 TNM classification, in which isolated tumor cells (<or=0.2 mm) were categorized as lymph node-negative disease, no stage migration was observed (P = .98). Also, when analyzing both hospitals (Hospital A vs Hospital B) separately with respect to lymph node involvement, there was no difference, between the SN era and the historic controls (P = .79 and P = .69, respectively). This remained nonsignificant after the analysis was corrected for patient and primary tumor characteristics (P = .85 and P = .66, respectively). CONCLUSIONS: Introduction of the SN procedure has led to the detection of more tumor-affected lymph nodes because of the intensified workup of SNs by pathologists. However, stage migration did not occur when tumor deposits of <or=0.2 mm were categorized as lymph node-negative disease, according to the 2002 TNM classification.
