Prognosis and local treatment strategies of breast cancer patients with different numbers of micrometastatic lymph nodes.

BACKGROUND: Lymph node micrometastasis is an important prognostic factor in breast cancer, but patients with different numbers of involved lymph nodes are all divided into the same N1mi stage without distinction. We designed this study to compare the prognosis and local treatment recommendations of N1mi breast cancer patients with different numbers of micrometastatic lymph nodes. PATIENTS AND METHODS: A total of 27,032 breast cancer patients with T1-2N1miM0 stage from the Surveillance, Epidemiology, and End Results (SEER) database (2004-2019) who underwent breast surgery were included in this retrospective study. Patients were divided into three groups for prognosis comparison according to the number of micrometastatic lymph nodes: N1mi with 1 (Nmi = 1), 2 (Nmi = 2), or more (Nmi ≥ 3) involved lymph nodes. We explored the characteristics and survival outcomes of the population receiving different local treatments, including different axillary surgery types and whether receiving radiotherapy or not. Univariate and multivariate Cox proportional hazards regression analysis were used to compare the overall survival (OS) and breast cancer-specific survival (BCSS) in different groups. Stratified analyses and interaction analyses were also applied to explore the predictive significance of different involved lymph nodes numbers. Propensity score matching (PSM) method was utilized to balance the differences between groups. RESULTS: Univariate and multivariate Cox regression analysis indicated that nodal status was an independent prognostic factor. After adjustment for other prognostic factors, there was a significant difference in prognosis between Nmi = 1 group and Nmi = 2 group [adjusted hazard ratio (HR) 1.145, 95% confidence interval (CI): 1.047-1.251, P = 0.003], and patients with Nmi ≥ 3 group had a significantly poorer prognosis (adjusted HR 1.679, 95% CI 1.589-2.407; P < 0.001). The proportion of N1mi patients only underwent sentinel lymph nodes biopsy (SLNB) gradually increased from 2010 (Ptrend < 0.001). After adjusting for other factors, N1mi patients who underwent axillary lymph nodes dissection (ALND) was associated with significant survival benefit than SLNB (adjusted HR 0.932, 95%CI 0.874-0.994; P = 0.033), the same goes for receiving radiotherapy (adjusted HR 1.107, 95%CI 1.030-1.190; P = 0.006). Further stratified analysis showed that in the SLNB subgroup, radiotherapy was associated with a significant survival benefit (HR 1.695, 95%CI 1.534-1.874; P < 0.001), whereas in the ALND subgroup, there was no significant prognostic difference with or without radiotherapy (HR 1.029, 95%CI 0.933-1.136; P = 0.564). CONCLUSION: Our study indicates that the increasing number of lymph node micrometastases was associated a worse prognosis of N1mi breast cancer patients. In addition, ALND does provide a significant survival benefit for these patients, while the benefit from local radiotherapy may be of even greater importance.

Sentinel lymph node mapping with patent blue dye in patients with breast cancer: a retrospective single institution study.

BACKGROUND: Since the end of the last century, sentinel lymph node biopsy (SLNB) has replaced axillary lymph node dissection (ALND) as standard of care for axillary staging in early breast cancer in patients without any clinical sign of axillary lymph node infiltration. The worldwide most frequently used mapping method consists in the injection of radioactive technetium-99 isotope alone or in combination with blue dye. As a specific infrastructure and dedicated personnel are needed for the use of a radioactive tracer, the CHC in Liege (Belgium) decided to test the use of patent blue dye alone to detect sentinel lymph nodes in a large consecutive cohort of patients and compared the results with radioactive mapping methods and guidelines recommendations. METHODS: Patent blue dye was used in 456 consecutive patients with early breast cancer who underwent conservative breast cancer surgery or radical mastectomy between 1/1/2000 and 31/12/2007 in a community hospital (CHC Liège, Belgium). After SLNB, an ALND was performed in each patient. RESULTS: Sentinel lymph nodes were identified in 444 patients among the 456 patients evaluated by this mapping method during this time period, which represents a detection rate of 97.4%. Infiltrated lymph nodes were detected in 32.7% of patients (149/456) while in the 444 patients with sentinel lymph nodes identified and resected, 137 patients have at last one positive lymph node (30.9%). The false negative rate was 4.9% and the predictive negative value was 97.7% with the blue dye mapping method. CONCLUSIONS: In addition of the simplicity of the method and the large economic advantage, SNLB using blue dye alone showed a quite acceptable performance in our retrospective analysis concerning its ability to find the SLN as well as its reliability to remove the good ones.