The clinical relevance of positive sentinel nodes only versus positive nonsentinel lymph nodes in breast cancer patients

Background The purpose of this study was to determine the difference in clinical outcomes for patients with histologically positive sentinel lymph nodes (SLN+) compared with patients with histologically positive nonsentinel second echelon lymph nodes (NSLN+). Methods Eight hundred thirteen node positive patients from a prospectively accrued database of 3,200 patients who underwent sentinel node mapping were evaluated. In all, 506 of the 813 patients (62%) were SLN+ only and 307 of the 813 patients (38%) were SLN+ plus at least one NSLN+. Patients' overall survival and disease-free survival were obtained and statistical analyses performed comparing the two groups. Results As the number of NSLN+ increased, there was a significant difference in disease-free survival (P = 0.001) and overall survival (P = 0.003) between those patients who had 0 to 4 NSLN+ and those who had 5 or more NSLN+. The SLN+ only patients did not show significant differences with respect to survival, based on the number of SLN+ (overall survival, disease-free survival; P = 0.742) Conclusions The survival (overall survival, disease-free survival) for patients with 3 or more SLN+ was not statistically different than for patients with 1 or 2 SLN+ (P = 0.742). However, an alteration of biologic behavior was observed when multiple NSLN+ contain metastatic breast cancer. Involvement of 5 or more NSLN+ portends a significantly (P = 0.001) worse prognosis, regardless of the number of SLN+.