The real-time intra-operative evaluation of sentinel lymph nodes in breast cancer patients using One Step Nucleic Acid Amplification (OSNA) and implications for clinical decision-making

INTRODUCTION

One Step Nucleic Acid Amplification (OSNA) method for the intraoperative analysis of sentinel lymph nodes (SLNs) in breast cancer, obviates a second operation to the axilla and thereby expedites progression to adjuvant therapy. Recent NICE guidelines have approved OSNA as a method of sentinel node diagnosis to support the above case.(1) METHOD: This is a single centre prospective cohort analysis of all patients undergoing breast cancer surgery including sentinel node biopsy from February 2010 to June 2012. Patients with negative SLN(s) on OSNA had no further axillary surgery. A validation phase was performed prior to using OSNA routinely. Those with micrometastases underwent a level 1 clearance, and >one SLN with macrometastases, underwent treatment by level 2 axillary dissection. The length of time from sentinel node retrieval to OSNA result was recorded.

RESULTS

Four hundred and forty nodes were analysed in 212 patients with a mean age of 55 years (range 24-98). The sensitivity and specificity of OSNA was 93% and 94% respectively in cases of macrometastases. The process required additional median anaesthesia time of 20 min (range -48 to +65 min). Non-sentinel node positivity was 5% and 48% for micrometastasis and macrometastasis respectively.

CONCLUSION

OSNA identified 62 of 212 patients with at least one positive sentinel node, thereby sparing 29% from a second procedure to clear the axilla subsequently. The median waiting time of 20 min for node results from completion of breast procedure is acceptable and allows for an efficient operating list. OSNA can be incorporated into routine practice and with improved methods of imaging preoperatively, can be an excellent adjunct to the breast cancer patient pathway of care.

Sentinel lymph node mapping in early breast cancer - Our experience

BACKGROUND

The axillary lymph node status is the most important determinant of prognosis in patients with breast cancer. Sentinel lymph node (SLN) biopsy is a safe alternative for axillary clearance with an equal efficacy limiting the morbidity caused by axillary clearance.

PATIENT AND METHODS

From May 1996 till September 2009, 523 clinically node negative, early breast cancer patients attending our clinic at All India Institute of Medical Sciences were included in the study. They underwent sentinel lymph node biopsy by either combined technique or blue dye alone. All patients irrespective of the axillary status underwent axillary lymph node dissection (ALND).

RESULTS

Of 523 patients, 267 underwent combined technique of sentinel node mapping and 256 underwent blue dye technique alone. The identification rate of sentinel lymph node was 94.3% (253/267) for combined technique and 87.8% (225/256) for blue dye alone. Of 523 patients SLN was identified in 478 patients. The identification rate was 91.3%. The sensitivity = 91.5% (141/154), false negative = 8.4% (13/154), negative predictive value = 96.14% (324/337), and accuracy being 97.2% (465/478).

CONCLUSION

Sentinel node mapping is a simple and safe technique of identifying the axillary node involvement. Sentinel lymph node biopsy is associated with less arm oedema and shoulder morbidity compared to ALND. However, the results of long term effects of sentinel node approach on tumor recurrence or patient survival are awaited.