The Shift From Sentinel Lymph Node Biopsy Performed Either Before or After Neoadjuvant Systemic Therapy in the Clinical Negative Nodes of Breast Cancer Patients. Results, and the Advantages and Disadvantages of Both Procedures.

BACKGROUND: In patients with breast cancer who are candidates for neoadjuvant therapy (NAT), the timing of when to perform sentinel lymph node biopsy (SLNB) remains under discussion. The aim of this study was to compare the advantages and disadvantages of SLNB performed before and after NAT. PATIENTS AND METHODS: One hundred seventy-two patients, T1c to T3 and N0 (clinically and according to ultrasound) candidates for NAT were included. We compared the outcomes of 2 groups: (1) 122 patients of whom SLNB was performed before NAT (pre-NAT) from December 2006 to April 2014; and (2) 50 patients with SLNB performed after NAT (post-NAT) from May 2014 to July 2016. RESULTS: Both groups were homogeneous in baseline patient characteristics. The SLNB was positive in 50 patients [41.7%] (33 macrometastases [66%] and 17 micrometastases [34%]) versus 6 patients [12%] (5 macrometastases [83.3%] and 1 micrometastases [16.7%]) in pre- and post-NAT groups, respectively. The lymphadenectomy was performed in 34 patients [28.3%] versus 4 patients [8%], with an odds ratio of 3.48 (95% confidence interval, 1.3-9.3). The recurrences in the pre-NAT group after a median follow-up of 62 months were 12 systemic, 2 local and systemic, and none axillary. In the post-NAT group were no recurrences after a median follow-up of 16 months. Finally, SLNB after NAT reduces the delay in starting NAT from 24 to 14 days (medians; P < .001) and the identification of the SLNB was in 122 patients [100%] versus 49 patients [98%]. CONCLUSION: SLNB performed after NAT significantly reduces the rate of lymphadenectomies without any increase in recurrences at early follow-up. Furthermore, it allows systemic treatment to be started earlier without interfering in the SLNB identification rate.

Feasibility, accuracy and prognosis of sentinel lymph node biopsy before neoadjuvant therapy in breast cancer. A prospective study.

BACKGROUND AND OBJECTIVE: It remains controversial whether sentinel lymph node biopsy (SLNB) should be performed before or after neoadjuvant therapy (NAT). We aimed to evaluate the feasibility and accuracy of SLNB before NAT at a single institution, and to determine its relation to patient prognosis. METHODS: A prospective study of T1c-T2-T3 N0 breast cancer patients, after ultrasound examination, who underwent SLNB prior to NAT. Overall, disease-specific and disease-free survival were calculated by Kaplan-Meier curves. RESULTS: SLNB before NAT was performed in 123 patients from December 2006 to May 2014. The identification rate was 100%. SLNB was positive in 42.3% of cases (27.6% macrometastases). NAT was chemotherapy in 88.6% of cases and endocrine-therapy in 11.4%. Lymphadenectomy was avoided in 72.4% of cases. Median follow-up was 40 months (range 8-100). Overall and disease-free survival was 90.2% and 88.6% respectively.SLN involvement was not related to patient outcome (p 0.72); however there were significant differences in survival according to molecular-like subtypes (p < 0.025) and NAT response (p < 0.0001). CONCLUSIONS: SLNB prior to NAT is an accurate method of axillary staging associated with a high identification rate. It avoided lymphadenectomy in more than 70% of patients. SLN involvement did not worsen the prognosis in our cohort.

Estudio comparativo entre el método One step nucleic acid amplification y el método convencional en la estadificación en cáncer de mama: un aumento en la detección de micrometástasis / Comparative study of the One step nucleic acid amplification method and the conventional method in axillary staging in breast cancer: an increase in the detection of micrometastases

Objetivos. El método One step nucleic acid amplification (OSNA) se ha incorporado para el estudio del ganglio centinela (GC) en cáncer de mama como alternativa al estudio convencional histológico (MC). El propósito de nuestro estudio fue comparar la estadificación por ganglio centinela (EGC) obtenida por el método OSNA con la obtenida mediante MC. Material y métodos. Se seleccionaron pacientes con cáncer de mama y EGC recogidas durante los años 2009-2010 y 2012-2013, estudiadas con MC y método OSNA. Se analizaron diferentes parámetros clínico-patológicos. Resultados. Se incluyó a 1.124 pacientes, 590 estudiadas por MC y 534 por método OSNA. La EGC inicial fue: pN0: MC 349 (59,2%) y OSNA 335 (62,7%); pN0(i+): MC 74 (12,5%) y OSNA 14 (2,6%); pN1mi: MC 59 (10%) y OSNA 77 (14,4%); pN1: MC 108 (18,3%) y OSNA 108 (20,3%). Se encontraron diferencias estadísticamente significativas entre la EGC por método OSNA y MC (p<0,001), a expensas de las tasas de pN1mi y pN0(i+). Se seleccionó a 224 pacientes con EGC pN1mi y pN0(i+) para determinar si las diferencias encontradas podrían atribuirse a distintas características clínico-patológicas. El método OSNA detecta el doble de micrometástasis (84,6%). Conclusiones. En nuestra casuística, por el método OSNA se observa un incremento significativo de pN1mi (84,6% vs. 44,4%) y una disminución de pN0(i+) respecto al estudio convencional, diferencias que no están condicionadas por los parámetros clínico-patológicos. El 75% de casos con pN1mi por OSNA muestra un número de copias inferior a 1.000 (AU)

Objetives. The One Step Nucleic Acid Amplification (OSNA) method has been incorporated in the study of the sentinel lymph node (SLN) in breast cancer as an alternative to conventional histological study. The aim of our study was to compare sentinel lymph node staging (SLNS) obtained by the OSNA method with that obtained by the conventional method (CM). Material and methods. We identified patients with breast cancer and SLN study during the periods 2009-2010 and 2012-2013, who underwent the CM and by OSNA. We analysed different clinicopathological parameters. Results. A total of 1124 patients were studied, 590 by CM and 534 by OSNA. SLNS was: pN0: CM 349 (59.2%) and OSNA 335 (62.7%); pN0(i+): CM 74 (12.5%) and OSNA 14 (2.6%); pN1mi: CM 59 (10%) and OSNA 77 (14.4%); pN1: CM 108 (18.3%) and OSNA 108 (20.3%). Statistically significant differences were found between the SLNS by OSNA and CM (p <0.001), due to the rates of pN1mi and pN0(i+). To determine whether this statistical significance could be attributed to different clinicopathological features, 224 patients were selected from the initial series with SLN pN1mi and pN0(i+). In this subgroup, the OSNA method detected twice as many micrometastases (pN1mi) (84.6%). Conclusions. In our series, the OSNA method resulted in a significant increase in pN1mi (84.6% vs 44.4%) and a decrease in pN0(i+) compared with the conventional method. Those differences were not affected by clinicopathological parameters. Most cases (75%) with pN1mi by OSNA showed less than 1000 copies (AU)