Title:
Diagnostic accuracy of sentinel lymph node biopsy in axillary lymph nodes at the early stages of breast cancer.

Abstract:
For almost 100 years, standard procedure for evaluation of axillary lymph status has been axillary nodes dissection (ALDN)-dissection of 1st, 2nd or possible 3rd level of axilla. Use of less invasive evaluation methods of axillary node pathologically (PH) status of non-invasive breast carcinoma has been started before about 30 year and that new method has been named sentinel lymph node biopsy (SLNB).
Primary objective of study is to establish specificity, sensitivity, positive and negative predictive value of SLNB method comparing to presents of malignant changes of axillary sentinel lymph node and to establish true indication for ALDN.
Study included 50 female patients, aged between 18-75, at Clinic for Glandular and Oncological Surgery, Clinical Center University of Sarajevo (CCUS), with non-invasive breast carcinoma, in the period from January 2008-January 2011, which fulfill established criteria.
The study is of retrospective-prospective, clinical-manipulative and descriptive-analytic character. Sample consisted of patients of Clinic for Glandular and Oncological Surgery with diagnosed breast carcinoma, at T1 and T2 stage, with adequate preoperative preparation. Preoperative imaging with injection of radioactive isotope Tc99m albumin-colloid is done at the Clinic for Nuclear Medicine CCUS. Intraoperative PH examination of SLN node (or nodes) by frozen-section and hematoxylin-eosin staining and postoperative PH examination of lymph nodes after ALND was done at the Institute for Clinical Pathology and Cytology CCUS. Intraoperative identification of SLN is done with manual gamma probe. After the SLNB, all the patients underwent immediately appropriate breast carcinoma surgeries followed with dissection of 1st and 2nd level of axilla on the Clinic for oncology and glandular surgery of CCUS.
Statistic data evaluation was done by statistical program Med Calc for Windows, version 12.2.1.0 (MedCalc Software Mariakerke, Belgium). In the part of descriptive statistics all results are shown in table manner: mean, 95% CI for average value, standard deviation, median values, 95% CI for median value, maximal value, 25-75 percentiles, evaluation of normal distribution by D'Agostino-Pearson test, Chi square test for evaluation of differences in frequencies between subgroups. For evaluations of specificity and sensitivity of results were applied 2 x 2 tables and following equations: sensitivity = TP/TP+LN, specificity = TN/P+TN, overall accuracy = TP+TN/N, positive predictive value = TP/TP+LP, negative predictive value = TN/LN+TN. Defined significance level was p < 0.05.
Results of sensitivity (68%), specificity (98%), positive (67%) and negative predictive value (96%) and overall accuracy of method (98%) are comparable and compatible with results from oncological breast cancer centers and allow introducing of SLNB in routine surgical practice in our clinical practice as the alternative for ALND for T1 and T2 breast carcinoma. It also contributes to better co-ordination between specialist of nuclear medicine, surgeon and pathologist.