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

Abstract

ObjetivesThe “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 methodsWe 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. ResultsA 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%). ConclusionsIn 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.