Prevalence of extracapsular extension in metastatic sentinel lymph nodes in breast cancer

Abstract

IntroductionAxillary lymph node involvement is recognized as a key prognostic factor for invasive breast cancer. Retrospective analyzes have shown that extracapsular extension (ECE) is correlated with negative prognostic factors in this neoplasia. Objectiveto evaluate the measurement of ECE and its relationship with the number of affected non-sentinel lymph nodes, as well as to investigate the association between ECE with other clinical and pathological prognostic factors. MethodsThis is a cross-sectional observational study carried out from January 2015 to June 2019, at the Breast Surgical Oncology service of Liga Contra o Cancer (LIGA), in Natal, Brazil. A total of 150 patients were included in the study and were divided into three groups: absence of ECE, ECE less than or equal to 2 mm and ECE greater than 2 mm. ResultsThe mean age was 58 years for the group with ECE and 57 years for the group without ECE. Most of the patients were mixed race (66.7%), had no family history of breast cancer (64%) and underwent quadrantectomy (64.5%). Regarding the characteristics of the disease, most presented a histological report compatible with Invasive Carcinoma of the non-special type (IC NST) (87.5%), histological grade II (52.7%), negative Lymphovascular invasion (LVI) (52.7%), Tumor Size T1 (<2.0 cm) (52%) and Luminal B molecular subtype (36.7%). Regarding sentinel lymph nodes: 103 patients (68.7%) had ECE and 1 positive sentinel lymph node was identified in most cases. There was a statistically significant association between the presence of ECE and of being mixed race (p = 0.03), between ECE and LVI (p = 0.05) and between ECE and a greater number of positive non-sentinel lymph nodes (p < 0.001). ConclusionOur study showed that ECE> 2 mm is associated with increased axillary nodal load compared to groups without ECE and ECE ≤ 2 mm in sentinel node biopsy in patients who met the Z0011 criteria.