Biopsia selectiva del ganglio centinela en el cáncer de mama

Abstract

INTRODUCTION: Sentinel lymph node biopsy consists of removing the lymph node which tumor drains. It is representative of the lymphatic drainage pathways of the tumor, and its affectation is conditioned for several factors. METHODS: Prospective, descriptive study with 302 patients treated with sentinel lymph node biopsy in Principe de Asturias Hospital over a period of March 2009 ‐ November 2012. Statistically significant variables predicting sentinel node and non‐sentinel node involvement were identified in logistic regression analysis: the age, status hormonal, the primary tumor size, histological type, histological and nuclear grade, ki‐67 status, subtipe molecular, multifocality, multicentricity, the presence of lymphovascular invasión (LVI), metastases in sentinel lymph node (SLN) with extracapsular extension, the size of the largest SLN metastases. OBJETIVES: 1. Principal objetive: Study the clinical and biology factors implicated in the presence of metastases in non‐SLN, to decide in which cases we can avoid a complete axillary dissection when the SLN is metastatic. 2. Secundary objetives: 1. Study the clinical and biology factors implicated in the presence of metastases in SLN. 2. Describe the epidemiologic, clinical, histological, surgical, immunohitochemical, and therapeutical characteristics of the patients treated with sentinel node biopsy. 3. Determine if the histologic study of SLN is able to predict safety the stage of the rest of the lymph nodes of axilla in patients with breast cancer. 4. Study the sensitivity and false‐negative rate of the histopatologic exam of SLN. 5. Recurrent axillary rate and survival in patients treated with sentinel lymph node biopsy. 6. Evaluate if the presence of micrometastases in SLN is associated with a worse prognosis. CONCLUSIONS: 1. The probability of metastases in non‐SLN increments with the presence of extracapsular extension of the metastatic SLN, with multifocality tumors, as the tumor size, histologic grade and number of SLN metastases increase. The group of patients with ≥ 2 SLN affected, has a probability of positive non‐SLN 3,85 higher to the group with 1 SLN positive (p=0,05). 2. When the SLN is metastatic, we can avoid the axillary lymph node dissection: with <3 SLN metastatic without extracapsular extension, unifocal tumors, T1 tumors, and adjuvant systemic and local therapy. 3. The probability of metastases in SLN increases significantly with large tumors, lymphovascular invasion, and in premenopausal patients. 4. The identification rate of SLN was 90,9%, and the fase‐negative rate 0%. 5. The histological study with haematoxylin/eosin and cytokeratin immunostaining has a sensitivity: 98%, specificity: 77%, positive and negative predictive value: 93%. 6. The presence of micrometastases does not affect survival outcomes. 7. The locorregional recurrent rate is very low (0,7%), and 0% the axillary recurrent rate.