Sentinel Node Ratio as a Predictor of Non-sentinel Lymph Node Involvement

Background: Sentinel lymph node biopsy (SLNB) has replaced axillarylymph node dissection (ALND) in early breast cancer patients as the first linesurgical approach to axillary nodes. Further dissection is performed only whenSLN is involved by tumor cells. However, in a significant proportion of patients,non-sentinel nodes are still not involved and axillary dissection has no additionaltherapeutic benefits. Selective axillary clearance has been considered to preventunnecessary dissection. The purpose of this study was to define predictors of nonsentinellymph node involvement in patientswith positive SLNB.Methods: Patients with early stage breast cancer and positive SLNB whounderwentALNDin a referral hospital inTehran, Iran between۲۰۱۰ and ۲۰۱۲wererecruited into the study. Relations between different clinico-pathologicalcharacteristics and involvement of non-sentinel nodes were investigated.Results: From ۱۳۹ patients who had positive SLNB and underwent ALND,only in ۷۱ cases (۵۱%) positive non-sentinel lymph nodes (NSLNs)were detected.In univariate analysis, there was no association between tumor size,lymphovascular invasion, ER, PR and HER-۲ expression and NSLN metastasis.In contrast, presence of more than one SLN (P = ۰.۰۱۶) and a sentinel node ratio(SNR) more than ۰.۵ showed a significant association (P< ۰.۰۰۱). Only the latterremained as the significant predictor of NSLN involvement in mutltivariateanalysis (P< ۰.۰۰۱,OR = ۳.۷۰۶).Conclusions: Based on our results, patients with a SNR more than ۰.۵ weremore commonly diagnosed with NSLN metastasis. Thus, it is recommended thatsurgeons think twice before skippingALNDin this subgroup of patients.

Keywords:

Sentinel lymph node ratio , non-sentinel lymph node , axillary dissection