Feasibility Study Of Methylene Blue Dye As A Single Tracer For Sentinel Lymph Node Biopsy In N+ Breast Cancer With Conversion Into N0 After Neoadjuvant Chemotherapy And The Influencing Factors

ObjectiveTo investigate the feasibility of methylene blue dye as a single tracer for sentinel lymph node biopsy in N+ breast cancer with conversion into N0 after neoadjuvant chemotherapy and the influencing factors.MethodsThirty-six,cN+ breast cancer with conversion into cN0 after neoadjuvant chemotherapy were subjected to SLNB(using methylene blue dye)followed by complete axillary lymph node dissection(levels I-?)and breast surgery.The sentinel node(s)was/were and the axilla were individually assessed histologically.The SLN accuracy parameters were calculated employing standard definitions.These patients were studied using descriptive statistics.Chi-square test(Fisher test was used if necessary)and paired T test were used to determine association between different variables.P value less than to 0.05 was taken as significant,with 95% confidence limits.ResultsThe SLN identification rate in the present study was 100%(36/36).The false negative rate of SLNB was 10.5%(2/19).The accuracy and sensitivity of SLNB were 94.4%(34/36)and 89.5%(17/19).And the negative sensitivity rate was 89.5%(17/19).A total of 130 sentinel nodes were identified and the average number of SLN harvested was 3.6 in each patient in our study.The menopausal,the diameter of mass(before or after NAC),pathological type,the effect of NAC,the location and the molecular typing of tumor had no effect on the identification rate and false negative rate of SLNB,but axillary lymph node status befor NAC was the factors that affected the identification rate of SLNB,however had no effect on the false negative rate.The SLN was found at level I in all cases and no untoward reaction to methylene blue dye was observed.ConclusionThis study confirms that SLNB using methylene blue dye as a sole mapping agent is reasonably safe and accurate to predict the status of axillary lymph nodes in cN1 breast cancer with conversion into cN0 after NAC but it is not recommended that this method is used in cN2 breast cancer before NAC.