Abstract
ABSTRACT Methods 412 patients (total study population) with clinically node negative early stage breast cancer underwent an axillary SLN in our institution. The SLN was assesed with OSNA in 168 patients. The OSNA results were compared with conventional histopathology results from 244 patients who has undergone a SLN biopsy few years earlier. Patients characteristics were evaluated in both groups and the rate of metastases detected by both methods and the surgical procedures were compared. Characteristics OSNA Cohort (n = 168) Historical cohort (n = 244) Age, median (range) 58 (33-86) 57 (30-93) Tumor size, mean (range) mm 16.63 (2-60) 14.16 (2-55) Tumor histology DCIS 18 8 Ductal invasive 130 192 Lobular invasive 12 25 Other subtypes invasive 8 19 Histological grade 1 56 100 2 77 88 3 35 17 Unknown 2 39 Oestrogen receptor Positive 220 143 Negative 24 25 Progesteron receptor Positive 126 202 Negative 42 42 HER2 status Positive 16 4 Negative 146 26 Unknown 6 214 Ki 67 ≤ 10% 72 95 > 10% 86 124 Unknown 10 25 Results SLN metastasis were found in 45 patientes in the OSNA group and in 49 in the historical group. There were no differences in rates of macrometastases (27 by OSNA, 41 by HE) and we found differences in micrometastasis rate (18 by OSNA and 8 by HE p =0.007). Axillary node dissection (ALND) was performed in 45 patients in the OSNA group and in 49 in the historical group. All the patients diagnosed by OSNA had a complete ALND during the initial surgical procedure. In the historical cohort the ALND was performed during the initial surgical procedure in 41 patients, and ALND was performed in a second surgical procedure in 8 patients. Conclusions The OSNA assay can detect SLN metastasis as accurately as conventional pathology with increased detection of micrometastasis. The second surgery can be reduced with the OSNA assay. Disclosure All authors have declared no conflicts of interest. The aim of this study is to present our first results with OSNA assays performed in a routine clinical setting in 168 patients with invasive and in situ breast cancer and compare them with conventional histopathology results for SLN biopsies in a historical cohort in our institution.
Highlights
Selective sentinel node biopsy has replaced axillary lymph node dissection due to its lower morbidity and equivalent prognosis in the long-term (Giuliano et al 1997; Krag et al 2010)
The purpose of this study is to present our first results with the one step nucleic acid amplification (OSNA) assay performed in a routine clinical setting in 163 patients with invasive and in situ breast cancer, examine their consistency with the classic HE study and evaluate the potential implications for the locorregional treatment of breast cancer patients
In the conventional IHC control group any kind of metastases were found in 71 cases (29%): 49 patients showed macrometastases (20%), 9 micrometastases (4%), and 13 presented ITC (5%)
Summary
Selective sentinel node biopsy has replaced axillary lymph node dissection due to its lower morbidity and equivalent prognosis in the long-term (Giuliano et al 1997; Krag et al 2010). The one-step acid amplification method (OSNA) detects and quantifies by polymerase chain reaction (PCR) the presence of mRNA of cytokeratin 19 in the whole node (Tsujimoto et al 2007). It is more time-consuming than the HE study but it can be performed intraoperatively (Osako et al 2011; Sagara et al 2011). The purpose of this study is to present our first results of sentinel node analysis (SLN) by one step nucleic acid amplification (OSNA) in routine clinical practice in our centre and compare them with the results of classic histopathological analysis in a historical cohort from our same institution
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