284P - Advantages of one step nucleic acid amplification (OSNA) whole node assay in sentinel lymph node (SLN) analysis in breast cancer

Date 01 October 2012
Event ESMO Congress 2012
Session Poster presentation III
Topics Breast Cancer, Early Stage
Presenter Ana Santaballa
Authors A. Santaballa1, H. De La Cueva2, C. Salvador2, A. Garcia Martinez3, M.J. Guarin3, D. Lorente2, L. Palomar2, I. Aznar4, F. Dobon4, P. Bello5
  • 1Hospital Universitari i Polit, ES-46026 - Valencia/ES
  • 2Medical Oncology, Hospital Universitari i Polit, ES-46026 - Valencia/ES
  • 3Pathology, HOSPITAL UNIVERSITARI I POLITECNIC LA FE, 46026 - VALENCIA/ES
  • 4Breast Unit, HOSPITAL UNIVERSITARI I POLITECNIC LA FE, 46026 - VALENCIA/ES
  • 5Nuclear Medicine, HOSPITAL UNIVERSITARI I POLITECNIC, 46026 - VALENCIA/ES

Abstract

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.

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.