Diagnostic performance of one-step nucleic acid amplification for intraoperative sentinel node metastasis detection in breast cancer patients

Diagnostic value of one-step nucleic acid amplification for sentinel lymph node metastasis in cytokeratin 19-positive tumors: evidence from bioinformatics and meta-analysis

Background

The status of the sentinel lymph nodes (SLNs) was an important prognostic factor in varies cancers. A one-step nucleic acid amplification (OSNA) assay, a molecular-based whole-node analysis method based on CK19 mRNA copy number, was developed to diagnose lymph node metastases. We aimed to evaluate the value of OSNA for the diagnosis of sentinel lymph node metastasis in CK19 positive cancers. CK19 mRNA and protein expression for pan-caner analysis were obtained from TCGA and the Human protein atlas database.

Methods

Two researchers independently searched the PubMed, Cochrane Library and Web of Science databases for qualified articles published before December 1, 2023. A meta-analysis was performed using MetaDisc and STATA. Risk bias and quality assessments of the included studies were evaluated, and a subgroup analysis was performed. Ten cancer types were found to be CK19 positively expressed and 7 of 10 had been reported to use OSNA for SLN detection.

Results

After literature review, there were 61 articles included in the meta-analysis, which consisted of 7115 patients with 18007 sentinel lymph nodes. The pooled sensitivity and specificity of OSNA were 0.87 and 0.95 in overall patients. Moreover, we found the background CK19 expression in normal tissue affected the diagnostic accuracy of OSNA. In breast cancer, we performed subgroup analysis. OSNA exhibited to be a stable method across different population groups and various medical centers. In addition, when 250 copies/μl was chosen as the cutoff point of CK19 mRNA, there were a relatively higher sensitivity and AUC in detecting SLN micro-metastasis than 5000 copies/μl.

Discussion

OSNA can predict the occurrence of SLN metastasis accurately in CK19 positive cancers, especially in breast cancer, colorectal cancer, lung cancer, gastric cancer and endometrial cancer. Our study warrants future studies investigating the clinical application of OSNA in pancreatic, ovarian and bladder cancers.

One-step nucleic acid amplification for intraoperative diagnosis of lymph node metastasis in lung cancer patients: a single-center prospective study

One-step nucleic acid amplification (OSNA) is a rapid intraoperative molecular detection technique for sentinel node assessment via the quantitative measurement of target cytokeratin 19 (CK19) mRNA to determine the presence of metastasis. It has been validated in breast cancer but its application in lung cancer has not been adequately investigated. 214 LNs from 105 patients with 100 primary lung cancers, 2 occult primary lung tumors, and 3 metastatic lung tumors, who underwent surgical lung resection with LN dissection between February 2018 and January 2020, were assessed. Resected LNs were divided into two parts: one was snap-frozen for OSNA and the other underwent rapidly frozen histological examination. Intraoperatively collected LNs were evaluated by OSNA using loop-mediated isothermal amplification and compared with intraoperative pathological diagnosis as a control. Among 214 LNs, 14 were detected as positive by OSNA, and 11 were positive by both OSNA and intraoperative pathological diagnosis. The sensitivity and specificity of OSNA was 84.6% and 98.5%, respectively. The results of 5 of 214 LNs were discordant, and the remainder all matched (11 positive and 198 negative) with a concordance rate of 97.7%. Although the analysis of public mRNA expression data from cBioPortal showed that CK19 expression varies greatly depending on the cancer type and histological subtype, the results of the five cases, except for primary lung cancer, were consistent. OSNA provides sufficient diagnostic accuracy and speed and can be applied to the intraoperative diagnosis of LN metastasis for non-small cell lung cancer.

Application of One-Step Nucleic Acid Amplification (OSNA) in different cancer entities and usefulness in prostate cancer: a systematic review

Background

Lymph node (LN) status is a key prognostic factor in the decision-making process of different cancer entities, including prostate cancer (PCa). Sectioning and haematoxylin and eosin (H&E) staining technique remain the gold standard for the evaluation of LN metastases despite some limitations, especially low sensitivity in detecting an accurate tumour burden within the LN, as well as a subjective and time-consuming result. One-step nucleic acid amplification (OSNA) quantifies mRNA copies of cytokeratin 19 (CK19) in a fast, objective, automated, and reproducible way, raising a general interest to explore its utility for lymphatic metastasis identification in different malignancies.

Methods

To present the latest evidence related to the detection of LN metastases in several tumours by using OSNA compared with the conventional H&E method, a systematic review of articles published since March 2021 was conducted using PubMed, Cochrane Library, and Web of Science databases. References from primary papers and review articles were checked to obtain further potential studies. Our procedure for evaluating records identified during the literature search followed the Preferred Reporting Items for Systematic Reviews and Meta-analyses criteria. With the aim to design and justify future clinical routine use of OSNA in PCa, novel PCa evidence has been included in this review for the first time.

Results

Twenty five studies were included. LN from six different groups of tumours: breast, gastrointestinal, gynecological, lung, head and neck and prostate cancers has been assessed. OSNA was compared with post-operative formalin-fixed paraffin-embedded tissue sections with H&E staining as the reference standard. Contingency tables were created, and concordance rate, sensitivity, specificity and predictive values were reported. Seventeen studies analysed the discordant cases using different techniques.

Conclusion

OSNA method has a high diagnostic accuracy for the detection of LN metastases in several CK19 expressing tumours. Available evidence might encourage future investigations about its usage in PCa patients to improve LN staging and prognosis.

Sentinel node involvement with or without completion axillary lymph node dissection: treatment and pathologic results of randomized SERC trial

Based on results of clinical trials, completion ALND (cALND) is frequently not performed for patients with breast conservation therapy and one or two involved sentinel nodes (SN) by micro- or macro-metastases. However, there were limitations despite a conclusion of non-inferiority for cALND omission. No trial had included patients with SN macro-metastases and total mastectomy or with >2 SN macro-metastases. The aim of the study was too analyze treatment delivered and pathologic results of patients included in SERC trial. SERC trial is a multicenter randomized non-inferiority phase-3 trial comparing no cALND with cALND in cT0-1-2, cN0 patients with SN ITC (isolated tumor cells) or micro-metastases or macro-metastases, mastectomy or breast conservative surgery. We randomized 1855 patients, 929 to receive cALND and 926 SLNB alone. No significant differences in patient’s and tumor characteristics, type of surgery, and adjuvant chemotherapy (AC) were observed between the two arms. Rates of involved SN nodes by ITC, micro-metastases, and macro-metastases were 5.91%, 28.12%, and 65.97%, respectively, without significant difference between two arms for all criteria. In multivariate analysis, two factors were associated with higher positive non-SN rate: no AC versus AC administered after ALND (OR = 3.32, p < 0.0001) and >2 involved SN versus ≤2 (OR = 3.45, p = 0.0258). Crude rates of positive NSN were 17.62% (74/420) and 26.45% (73/276) for patient’s eligible and non-eligible to ACOSOG-Z0011 trial. No significant differences in patient’s and tumor characteristics and treatment delivered were observed between the two arms. Higher positive-NSN rate was observed for patients with AC performed after ALND (17.65% for SN micro-metastases, 35.22% for SN macro-metastases) in comparison with AC administered before ALND.

Prognostic Significance of Lymph Node Examination by the OSNA Method in Lung Cancer Patients-Comparison with the Standard Histopathological Procedure

The aim of the study was to compare the prognostic significance of lymph node status of patients with lung cancer analyzed by three different methods: hematoxylin and eosin (H&E), immunohistochemistry of cytokeratin 19 (IHC CK19), and One-Step Nucleic Acid Amplification (OSNA). The clinical relevance of the results was evaluated based on relation to prognosis; the disease-free interval (DFI) and overall survival (OS) were analyzed. During radical surgical treatment, a total of 1426 lymph nodes were obtained from 100 patients, creating 472 groups of nodes (4–5 groups per patient) and examined by H&E, IHC CK19 and OSNA. The median follow-up was 44 months. Concordant results on the lymph node status of the H&E, IHC CK19 and OSNA examinations were reported in 78% of patients. We recorded shorter OS in patients with positive results provided by both OSNA and H&E. The study demonstrated a higher percentage of detected micrometastases in lymph nodes by the OSNA method. However, the higher sensitivity of the OSNA, with the cut-off value 250 copies of mRNA of CK19/µL, resulted in a lower association of OSNA positivity with progress of the disease compared to H&E. Increasing the cut-off to 615 copies resulted in an increase in concordance between the OSNA and H&E, which means that the higher cut-off is more relevant in the case of lung tumors.

The performance of one-step nucleic acid amplification assay for intraoperative detection of sentinel lymph node macrometastasis in breast cancer: An updated meta-analysis

BACKGROUND

One-step nucleic acid amplification (OSNA) assay is a molecular diagnostic method for intraoperative detection of lymph node metastasis by amplifying cytokeratin 19 mRNA. We aim to further evaluate the performance of OSNA assay for the intraoperative diagnosis of sentinel lymph node metastasis in breast cancer.

METHODS

PubMed, Cochrane Library, Web of Science databases were searched to retrieve related literature published up until December 2017. This meta-analysis was performed using a random-effects model. Risks of bias and quality assessments of included studies were evaluated and subgroup analysis was performed.

RESULTS

Nineteen studies were included in this meta-analysis. For overall metastasis, the pooled sensitivity, specificity and area under the summary receiver-operating characteristic curve (AUC) were 0.90, 0.96 and 0.98, respectively. For macrometastasis, the pooled sensitivity, specificity and AUC were 0.85, 0.98 and 0.94, respectively.

CONCLUSION

OSNA assay is an accurate molecular diagnosis for intraoperative detection of sentinel lymph node macrometastasis in breast cancer.

A more sensitive detection of micrometastases of NSCLC in lymph nodes using the one-step nucleic acid amplification (OSNA) method

BACKGROUND

Detection of tumor cells in lymph nodes (LNs) removed during the treatment of pulmonary tumor by radical surgery is limited by the possibilities of standard histopathological methods. The goal of this study was to obtain more accurate pTNM status by a more sensitive detection of micrometastases in LNs.

METHODS

A total of 885 LNs, an average of 13.8 LNs per patient, were removed during 64 surgeries. LNs from the same zone were pooled together as a group, five groups of LNs were examined in each patient. A total of 320 groups of LNs were examined. One-step nucleic acid amplification (OSNA) method was compared to standard histopathological examination with haematoxylin-eosin (H&E) staining and CK19 immunohistochemistry, specifically by an ultimate analysis of all intraoperatively removed LNs.

RESULTS

Identical results for H&E and OSNA examinations were recorded in 286 groups of LNs (89.4%). In total, positive examinations were recorded in 27 groups of LNs (8.4%) using the OSNA method, which were H&E negative. In seven groups of LNs (2.2%), the H&E examination was positive, while OSNA method produced negative results.

CONCLUSIONS

The OSNA examination led to a higher pTNM stage classification in 14 (21.9%) patients. The clinical significance remains the subject of follow-up research.

One-step nucleic acid amplification assay is an accurate technique for sentinel lymph node biopsy of breast cancer patients: a meta-analysis

Background:

To estimate the accuracy of one-step nucleic acid amplification (OSNA) assay as an intra-operative sentinel lymph node biopsy (SLNB) for sentinel lymph node (SLN) metastasis in breast cancer.

Methods:

PubMed, Cochrane Library and Web of Science databases were searched by two independent reviewers to retrieve literature with per-patient analysis. The deadline was up until December 2016. A meta-analysis was performed using STATA, Meta-Disc, and Revman software. A random-effects model was used and subgroup analysis was carried out to identify possible sources of heterogeneity.

Results:

According to the inclusion criteria, 2833 patients from 12 studies were included in this meta-analysis. The pooled sensitivity, specificity, positive likelihood ratio (PLR), negative likelihood ratio (NLR), diagnostic odds ratio (DOR) and the area under the sROC curve (AUC) for detecting SLN metastasis were 0.87 (95% CI 0.81–0.91), 0.92 (95% CI 0.86–0.95), 10.65 (95% CI 6.18–18.34), 0.14 (95% CI 0.10–0.20), 75.08 (95% CI 37.77–149.22) and 0.94 (95% CI 0.91–0.95), respectively.

Conclusions:

The present study adds the evidence that OSNA assay is an accurate molecular diagnostic tool for intra-operatively detecting SLN metastasis in breast cancer. One-step nucleic acid amplification assay might be introduced into clinical usage for replacing traditional intro-operative diagnostic methods of SLNB.

Association of One-Step Nucleic Acid Amplification Detected Micrometastases with Tumour Biology and Adjuvant Chemotherapy

One-step nucleic acid amplification (OSNA) is an intraoperative technique with a high sensitivity and specificity for sentinel node assessment. The aim of this study was to assess the impact of OSNA on micrometastases detection rates and use of adjuvant chemotherapy. A retrospective review of patients with sentinel node micrometastases over a five-year period was carried out and a comparison of micrometastases detection using OSNA and H&E techniques was made. Out of 1285 patients who underwent sentinel node (SLN) biopsy, 76 patients had micrometastases. Using H&E staining, 36 patients were detected with SLN micrometastases (9/year) in contrast to 40 patients in the OSNA year (40/year) (p < 0.0001), demonstrating a fourfold increase with the use of OSNA. In the OSNA group, there was also a proportional increase in Grade III, triple-negative, ER-negative, and HER-2-positive tumours being diagnosed with micrometastases. Also on interactive PREDICT tool, the number of patients with a predicted 10-year survival benefit of more than 3% with adjuvant chemotherapy increased from 52 to 70 percent. OSNA has resulted in an increased detection rate of micrometastases especially in patients with aggressive tumour biology. This increased the number of patients who had a predicted survival benefit from adjuvant chemotherapy.

A cut-off of 2150 cytokeratin 19 mRNA copy number in sentinel lymph node may be a powerful predictor of non-sentinel lymph node status in breast cancer patients

Since 2007, one-step nucleic acid amplification (OSNA) has been used as a diagnostic system for sentinel lymph node (SLN) examination in patients with breast cancer. This study aimed to define a new clinical cut-off of CK19 mRNA copy number based on the calculation of the risk that an axillary lymph node dissection (ALND) will be positive. We analyzed 1529 SLNs from 1140 patients with the OSNA assay and 318 patients with positive SLNs for micrometastasis (250 copies) and macrometastasis (5000 copies) underwent ALND. Axillary non–SLNs were routinely examined. ROC curves and Youden’s index were performed in order to identify a new cut-off value. Logistic regression models were performed in order to compare OSNA categorical variables created on the basis of our and traditional cut-off to better identify patients who really need an axillary dissection. 69% and 31% of OSNA positive patients had a negative and positive ALND, respectively. ROC analysis identified a cut-off of 2150 CK19 mRNA copies with 95% sensitivity and 51% specificity. Positive and negative predictive values of this new cut-off were 47% and 96%, respectively. Logistic regression models indicated that the cut-off of 2150 copies better discriminates patients with node negative or positive in comparison with the conventional OSNA cut-off (p<0.0001). This cut-off identifies false positive and false negative cases and true-positive and true negative cases very efficiently, and therefore better identifies which patients really need an ALND and which patients can avoid one. This is why we suggest that the negative cut-off should be raised from 250 to 2150. Furthermore, we propose that for patients with a copy number that ranges between 2150 and 5000, there should be a multidisciplinary discussion concerning the clinical and bio-morphological features of primary breast cancer before any decision is taken on whether to perform an ALND or not.

Is intraoperative touch imprint cytology indicated in the surgical treatment of early breast cancers?

INTRODUCTION

Intraoperative touch imprint cytology (TIC) of the sentinel lymph node(s) (SLN(s)) in the treatment of breast cancer has significantly reduced the number of axillary block dissections (ABD) required during second surgeries. Based on recent studies, ABD was not considered necessary if the presence of tumor cells/micrometastasis was confirmed in the SLN(s) or in the case of macrometastases in a patient group meeting the inclusion criteria for the ACOSOG Z0011 study. Our aim was to determine the sensitivity and usefulness of TIC with regard to these results.

METHODS

TICs of the SLN(s) were examined in 1168 patients operated on for breast cancer. The method was also analyzed retrospectively based on the guidelines for the Z0011 study. During TIC, new samples were cut every 250 μm; impression smears were evaluated after being stained with hematoxylin eosin.

RESULTS

TIC confirmed metastasis in 202 cases (202/1168, 17.29%). Metastasis was confirmed in SLN(s) in 149 additional cases during a final histological examination. The sensitivity of TIC was found to be 57.18%, and its specificity was 99.63%. An analysis was then performed except for cases that met the inclusion criteria for the Z0011 study and with metastasis smaller than 2 mm (micrometastasis/isolated tumor cells) considered to be positive during intraoperative cytology. The sensitivity of the method decreased to 34.23%, while its specificity was still high at 99.76%.

CONCLUSIONS

Based on the new guidelines for ABD, imprint cytology cannot be considered a beneficial and cost-effective intervention in the surgical treatment of early breast cancer.

Intraoperative diagnosis of sentinel lymph node metastases in breast cancer treatment with one-step nucleic acid amplification assay (OSNA)

INTRODUCTION

The aim of the study was to evaluate the clinical usefulness of a one-step nucleic acid amplification assay (OSNA) for intraoperative detection of metastases to sentinel lymph nodes (SLNs) in comparison to examination of frozen sections, and to summarize the results of previous studies.

MATERIAL AND METHODS

We enrolled 98 patients aged 58.13 ±10.74 years treated surgically for breast cancer, and 99 biopsies of SLNs were followed by analysis of 105 SLNs. The central 1 mm slice of SLN was used for examination of frozen sections, whereas 2 outer slices of SLNs were analyzed intraoperatively with OSNA. Detection of isolated tumor cells (ITC), micrometastases or macrometastases with OSNA extended surgery to axillary lymph node dissection. Congruency of results was assessed between OSNA and examination of frozen sections.

RESULTS

One-step nucleic acid amplification assay detected metastases in 29/105 SLNs in surgery of 27/99 breasts, including ITC in 3/29 SLNs, micrometastases in 12/29 and macrometastases in 14/29. One-step nucleic acid amplification assay detected significantly more metastases to SLNs than examination of frozen sections (p < 0.0001). All 8 inconsistent results were positive in OSNA and negative in examination of frozen sections; ITC were identified in 2/8 SLNs and micrometastases in 6/8 SLNs. Sensitivity for OSNA was calculated as 100%, specificity as 90.47%, and κ was 79.16%.

CONCLUSIONS

One-step nucleic acid amplification assay analysis allows rapid and quantitative detection of mRNA CK19 with high specificity and a low rate of false positives. One-step nucleic acid amplification assay is a reliable tool for intraoperative diagnosis of whole SLNs during surgery of breast cancer. One-step nucleic acid amplification assay minimizes the need for secondary surgery and avoids delays in the adjuvant treatment.

Sentinel lymph nodes for breast carcinoma: an update on current practice

Sentinel lymph node (SLN) biopsy has been established as the standard of care for axillary staging in patients with invasive breast carcinoma and clinically negative lymph nodes (cN0). Historically, all patients with a positive SLN underwent axillary lymph node dissection (ALND). The ACOSOG Z0011 trial showed that women with T1-T2 disease and cN0 who undergo breast-conserving surgery and whole-breast radiotherapy can safely avoid ALND. The main goal of SLN examination should be to detect all macrometastases (>2 mm). Gross sectioning of SLNs at 2-mm intervals and microscopic examination of one haematoxylin and eosin-stained section from each SLN block is the preferred method for pathological evaluation of SLNs. The role and timing of SLN biopsy for patients who have received neoadjuvant chemotherapy is controversial, and continues to be explored in clinical trials. SLN biopsies from patients with invasive breast carcinoma who have received neoadjuvant chemotherapy pose particular challenges for pathologists.

A systematic review and economic evaluation of intraoperative tests [RD-100i one-step nucleic acid amplification (OSNA) system and Metasin test] for detecting sentinel lymph node metastases in breast cancer

BACKGROUND

In breast cancer patients, sentinel lymph node biopsy is carried out at the same time as the removal of the primary tumour to postoperatively test with histopathology for regional metastases in the sentinel lymph node. Those patients with positive test results are then operated on 2-4 weeks after primary surgery to remove the lymph nodes from the axilla (axillary lymph node dissection, ALND). New molecular tests RD-100i [one-step nucleic acid amplification (OSNA); based on messenger RNA amplification to identify the cytokeratin-19 (CK19) gene marker] (Sysmex, Norderstedt, Germany) and Metasin (using the CK19 and mammaglobin gene markers) (Cellular Pathology, Princess Alexandra Hospital NHS Trust, Harlow, UK) are intended to provide an intraoperative diagnosis, thereby avoiding the need for postoperative histopathology and, in positive cases, a second operation for ALND.

OBJECTIVE

To evaluate the clinical effectiveness and cost-effectiveness of using OSNA and Metasin in the NHS in England for the intraoperative diagnosis of sentinel lymph nodes metastases, compared with postoperative histopathology, the current standard.

DATA SOURCES

Electronic databases including MEDLINE, MEDLINE In-Process & Other Non-Indexed Citations, EMBASE, The Cochrane Library and the Health Economic Evaluations Database as well as clinical trial registries, grey literature and conference proceedings were searched up to July 2012.

REVIEW METHODS

A systematic review of the evidence was carried out using standard methods. Single-gate studies were used to estimate the accuracy of OSNA with histopathology as the reference standard. The cost-effectiveness analysis adapted an existing simulation model of the long-term costs and health implications of early breast cancer diagnostic outcomes. The model accounted for the costs of an extended first operation with intraoperative testing, the loss of health-related quality of life (disutility) from waiting for postoperative test results, disutility and costs of a second operation, and long-term costs and disutility from lymphoedema related to ALND, adjuvant therapy, locoregional recurrence and metastatic recurrence.

RESULTS

A total of 724 references were identified in the searches, of which 17 studies assessing test accuracy were included in the review, 15 on OSNA and two on Metasin. Both Metasin studies were unpublished. OSNA sensitivity of 84.5% [95% confidence interval (CI) 74.7% to 91.0%] and specificity of 91.8% (95% CI 87.8% to 94.6%) for patient nodal status were estimated in a meta-analysis of five studies [unadjusted for tissue allocation bias (TAB)]. At these values and a 20% node-positive rate, OSNA resulted in lifetime discounted cost-savings of £498 and a quality-adjusted life-year (QALY) loss of 0.048 relative to histopathology, that is, £4324 saved per QALY lost. The most favourable plausible scenario for OSNA in terms of the node-positive rate (range 10-40%), diagnostic accuracy values (91.3% sensitivity and 94.2% specificity, from three reports that adjusted for TAB), the costs of histopathology, OSNA and second surgery, and long-term costs and utilities resulted in a maximum saving per QALY lost of £10,500; OSNA sensitivity and specificity would need to be ≥ 95% for this figure to be ≥ £20,000.

LIMITATIONS

There is limited evidence on the diagnostic test accuracy of intraoperative tests. The quality of information on costs of resource utilisation during the diagnostic pathway is low and no evidence exists on the disutility of waiting for a second surgery. No comparative studies exist that report clinical outcomes of intraoperative diagnostic tests. These knowledge gaps have more influence on the decision than current uncertainty in the performance of postoperative histopathology in standard practice.

CONCLUSIONS

One-step nucleic acid amplification is not cost-effective for the intraoperative diagnosis of sentinel lymph node metastases. OSNA is less accurate than histopathology and the consequent loss of health benefits in this patient group is not compensated for by health gains elsewhere in the health system that may be obtained with the cost-savings made. The evidence on Metasin is insufficient to evaluate its cost-effectiveness.

STUDY REGISTRATION

This study is registered as PROSPERO CRD42012002889.

FUNDING

The National Institute for Health Research Health Technology Assessment programme.

One-Step Nucleic Acid Amplification Assay for Detection of Axillary Lymph Node Metastases in Breast Cancer Patients Treated with Neoadjuvant Chemotherapy

BACKGROUND

The accuracy of one-step nucleic acid amplification (OSNA) for the detection of lymph node (LN) metastasis in breast cancer patients has been well established. This study aimed to evaluate its accuracy for patients treated with neoadjuvant chemotherapy (NAC).

METHODS

For this study, 300 LNs, 115 sentinel lymph nodes (SLNs), and 185 non-SLNs from 88 breast cancer patients treated with NAC were examined by means of histology (hematoxylin and eosin staining and pancytokeratin immunostaining) and OSNA.

RESULTS

The diagnostic accuracy, sensitivity, and specificity of OSNA were respectively 92.3, 88.5, and 93.3 % for all LNs, and the corresponding values were 87.8, 75.0, and 91.2 % for SLNs and 95.1, 97.3, and 94.6 % for non-SLNs. The diagnostic accuracy of OSNA was significantly lower for SLNs than for non-SLNs (P = 0.021), which was attributable to the low sensitivity for detection of micrometastases (micromets) due to lower CK19 mRNA expression detected by in situ hybridization (ISH) in SLN micromets than in non-SLN micromets. For primary breast tumors, CK19 mRNA expression showed a significant reduction after NAC (P = 0.040).

CONCLUSIONS

The diagnostic accuracy of OSNA for NAC-treated patients is similar to that for NAC-nontreated patients, but its accuracy is significantly lower for SLNs than for non-SLNs. The findings obtained with CK19 mRNA ISH suggest that most SLN micromets cannot be detected by OSNA due to the reduced expression of CK19 mRNA induced by NAC.

Clinical significance of breast cancer micrometastasis in the sentinel lymph node

The advantages of sentinel lymph node biopsy (SLNB) in breast cancer patients include an enhanced pathological examination of a small number of sentinel lymph nodes (SLNs), which permits more frequent detection of micrometastasis and isolated tumor cells (ITCs). At the same time, however, SLNB raises two new concerns: whether minimal SLN involvement has a significant impact on survival and whether patients with such minimal involvement should undergo further axillary dissections. Two large randomized studies, ACOSOG Z0011 and IBCSG 23-01, have demonstrated that axillary lymph node dissection (ALND) can be avoided for select SLN-positive patients. However, for patients with macrometastasis in SLN or who do not meet the inclusion criteria of the two studies, ALND is still the standard management. On the other hand, previous studies appear to disagree on the prognostic significance of minimal SLN involvement. One of the reasons for this discrepancy is the great variability among pathological examinations for SLN. The OSNA method, which is a fast molecular detection procedure targeting cytokeratin 19 (CK19) mRNA, has the advantage of reproducibility among institutions and the capability to examine a whole lymph node within 30-40 min. This novel method may thus be able to overcome the issue of variability among conventional pathological examinations.

Clinical usefulness of one-step nucleic acid amplification assay in the new era of sentinel lymph node biopsy for breast cancer

SUMMARY 

According to the results of the ACOSOG Z0011 trial and IBCSG trial 23-01, rapid intraoperative examinations of the sentinel lymph nodes (SLN) are needed in only a limited number of breast cancer patients, including those with more than three sentinel nodes or who undergo mastectomy. In this new era of SLN biopsies, one-step nucleic acid amplification assay is a promising method for accurately assessing metastasis in the whole SLN, and which help to accurately select patients requiring axillary dissection and reliably evaluate the risk of recurrence. One-step nucleic acid amplification assay may therefore be an alternative to conventional pathology in detecting metastasis in the SLNs, when used for both intraoperative and postoperative examinations.

An intra-operative RT-LAMP method allows rapid and reliable detection of sentinel lymph node metastasis in breast cancer patients

The rapid determination of metastasis in sentinel lymph nodes (SLNs) of breast cancer patients plays a significant role in the selection of a surgery strategy. Although a previous one-step nucleic acid amplification assay that uses reverse-transcription (RT) loop-mediated isothermal amplification (LAMP) has showed specific advantages over traditional pathological examination, its target marker requires optimisation. In addition to epithelial-specific CK19, the internal control gene PBGD and the breast-specific PIP were included in the new method. After the RT-LAMP primers were designed and verified using a cell line, the performance of our method was evaluated by comparing it with the corresponding result of the Food and Drug Administration approved breast lymph node (BLN) assay and routine pathological examination. One hundred and seventy-four valid SLN samples from 101 patients were collected from five hospitals. The threshold of reaction time for CK19, PIP and PBGD was defined as 16, 20 and 20 min, respectively. Compared with the BLN assay, the concordance rate of our method was 95.4% (166/174). Statistical analysis revealed that the two methods are consistent (kappa = 0.890, P < 0.001). When compared with pathological examination, the performance of our method (sensitivity = 81.3%, specificity = 89.7%, kappa = 0.691, P < 0.001) was similar to that of the BLN assay (sensitivity = 87.5%, specificity = 84.9%, kappa = 0.668, P < 0.001). This result demonstrates the potential usefulness of our method in clinical practice. In conclusion, we preliminarily established an intra-operative diagnostic method that assimilates the merits of previous assays. In contrast with the BLN assay and pathological examination, our method can be completed in 30 min and shows high sensitivity, specificity and consistency, which we consider as promising for clinical application.

OSNA (one-step nucleic acid amplification) sentinel lymph node intraoperative molecular analysis in breast cancer: a cost-benefit analysis

The aim of the study was to analyze the medical and economic interest of OSNA molecular technique, compared to conventional postoperative histopathologic evaluation for sentinel lymph node exploration in breast cancer patients. This retrospective cost-benefit study was conducted in the French Universitary Hospital of Saint Etienne on patients who received sentinel lymph node exploration between July 1, 2007 and December 31, 2009. Lymph nodes were analyzed by conventional postoperative histological evaluation in group 1 (82 patients) and OSNA in group 2 (86 patients). Costs were analyzed in three different ways: surgery cost, hospitalization cost and histopathologic cost. Average operating time was slightly shorter for group 1 (histology) [71.9 vs. 76.8 min for group 2 (OSNA)]. Time and operating costs were not significantly different (p = 0.293). The average cost of pathological examination was significantly higher in group 2 (35.04 euros per node in group 1 vs. 291.84 euros per node in group 2 p < 10(-3)). The average length of hospital stay was significantly longer in group 1 (5.4 days in group 1 vs. 4.2 days in group 2, p = 0.0065). The total costs were not significantly different between both groups (3,774.6 euros in group 1 vs. 3,393.9 euros in group 2 p = 0.055). The sentinel lymph node analysis with OSNA technique does not lead to higher expenses. It also avoids another surgery for 20% of patients. A prospective multicentric medico-economic study made with a larger effective would probably confirm these results.

Assessment of suitability of the one step nucleic acid amplification (OSNA) assay as an intraoperative procedure for detection of metastasis in sentinel lymph nodes of breast cancer

AIM

We aimed to assess the one step nucleic acid amplification (OSNA) assay as an intraoperative method in comparison with frozen sections (FS) for detection of metastasis in sentinel lymph nodes (SLNs) of breast cancer.

METHOD

100 SLNs from patients with breast carcinoma were enrolled within a 3-month period. Alternate 2 mm node slices were subjected to routine FS, and later to permanent histology, and the rest for automated molecular detection of CK19 mRNA using OSNA. FS and OSNA findings were compared with permanent histology results. Difference in turnaround time was also noted.

RESULTS

With permanent histology as gold standard, OSNA was discrepant in 8 of 98 (3 false negative, 5 false positive) included SLNs whereas FS had 2 false negative cases. FS had higher sensitivity (89%, p=<0.001), specificity (100%, p=0.001) and concordance rate (98%) than OSNA (83%, 94% and 92%, respectively). FS showed almost perfect agreement (κ=0.929) whereas OSNA showed substantial agreement (κ=0.740) when compared with permanent histology. OSNA turnaround time was twice longer (mean of 47.7 min) than FS.

CONCLUSIONS

Automation of SLN assessment using OSNA is a potentially useful intraoperative diagnostic tool with acceptable accuracy. Discordant findings in this study may be due to sampling allocation. Since OSNA is more time-consuming, its practical advantage over routine FS requires further study in view of current technical workflow considerations.

A new clinical cut-off of cytokeratin 19 mRNA copy number in sentinel lymph node better identifies patients eligible for axillary lymph node dissection in breast cancer

AIMS

Cytokeratin 19 (CK19) mRNA copy number predicts the probability of tumour load in axillary lymph nodes (ALN) and can help in decision-making regarding the axillary dissection. The purpose of this study was to define a new cut-off of CK19 mRNA copy number using the one-step nucleic acid amplification (OSNA) assay on metastatic sentinel lymph nodes (SLN) in order to identify cases at risk of having one or more positive ALN.

METHODS

1296 SLN from 1080 patients were analysed with the OSNA assay. 194 patients with positive SLN underwent ALN dissection and the mean value of CK19 copy number (320 000) of their SLN was set as initial cut-off. Receiver operative characteristics curve identify a best cut-off of 7700 (sensitivity 78%, specificity 57%). A comparison between our and the traditional cut-off (5000) was performed.

RESULTS

The cut-off of 7700 successfully identifies patients with positive ALN (p=0.001, false- negative cases: 17%). In the range between 5000 and 7700, one patient with positive ALN would not undergo axillary dissection, whereas eight patients with negative ALN would be correctly identified.

CONCLUSIONS

We suggest that the level of CK19 mRNA copy number could be the only parameter to consider in the intraoperative management of the axilla.

Detailed evaluation of one step nucleic acid (OSNA) molecular assay for intra-operative diagnosis of sentinel lymph node metastasis and prediction of non-sentinel nodal involvement: experience from a London teaching hospital

One step nucleic acid (OSNA) is a molecular diagnostic assay for intra-operative detection of sentinel node metastases. This study compared OSNA with standard histopathology in 283 nodes from 170 patients to evaluate sensitivity, specificity and concordance of the two methods. Additional analysis was done to investigate how cytokeratin 19 mRNA copy number affects prediction of non-sentinel node positivity. OSNA sensitivity was 93.2% and specificity 95.8%. Concordance between OSNA and histology was 95.6%. In the patients who had axillary clearance, the OSNA mRNA copy number on the sentinel node had 100% negative predictive value for histologically proven metastasis. mRNA copy numbers <1400 were not associated with histologically proven metastasis in subsequent nodes at axillary clearance. OSNA is a reliable method for the intra-operative evaluation of axillary lymph node metastasis even when half of the lymph node is used. Identification of mRNA copy number threshold predicting the positivity of non-sentinel axillary nodes seems to be feasible and would be clinically important.

Systematic review and meta-analysis of cytokeratin 19-based one-step nucleic acid amplification versus histopathology for sentinel lymph node assessment in breast cancer

Background

One-step nucleic acid amplification (OSNA) is a new rapid assay for detecting breast cancer metastases during surgery, saving a second procedure for patients requiring an axillary clearance. Many centres in the UK and abroad have adopted OSNA in place of routine histopathology, despite no published meta-analysis. The aim of this systematic review and meta-analysis was to determine whether intraoperative OSNA for lymph node assessment is comparable to routine histopathology in the detection of clinically relevant metastases.

Methods

PubMed, Embase, Web of Knowledge and regional databases were searched for relevant studies published before December 2012. Included studies compared OSNA and standard histology using fresh lymph nodes that were assessed in a clearly defined systematic manner in accordance with the index study.

Results

Twelve eligible studies were identified that included 5057 lymph nodes from 2192 patients. Although meta-analysis using a random-effects model showed a similar overall proportion of macrometastases detected (429 of 3234 versus 432 of 3234; odds ratio 0·99, 95 per cent confidence interval 0·86 to 1·15), analysis of concordance showed that the pooled positive predictive value for detecting macrometastases was 0·79. This suggests that up to 21 per cent of patients found to have macrometastases using OSNA would have an axillary clearance when histology would have classified the deposits as non-macrometastases. Furthermore, analysis of data from the index publication showed that the range of cytokeratin 19 titres for tumours of a given volume is too wide to predict tumour size.

Conclusion

OSNA has an unacceptably low positive predictive value, leading to axillary clearances that would not be recommended if standard histology had been used to assess the sentinel node.

Is the one-step nucleic acid amplification assay better for intra-operative assessment of breast sentinel nodes?

BACKGROUND

Intra-operative assessment of sentinel lymph nodes in breast cancer offers the opportunity to prevent two-stage surgical procedures. At our institution we employ touch imprint cytology (TIC), which lacks sensitivity. In this study we compare the one-step nucleic acid amplification (OSNA) assay to TIC.

METHODS

Imprints were taken from 63 lymph nodes from 35 patients. The lymph nodes were sectioned at 2-mm intervals and alternate slices submitted for either histology or OSNA assay, with histology as the reference standard.

RESULTS

Seven patients were histologically positive. Nine and five patients were positive by OSNA and TIC, respectively. Sensitivity, specificity, positive and negative predictive value for the OSNA assay were 85.7%, 85.7%, 63.6% and 96.6% and for TIC were 70.0%, 96.6%, 87.5% and 90.3%.

CONCLUSION

In this study OSNA had a higher sensitivity than TIC. Fewer patients assessed by the OSNA assay would have required a two-stage procedure. The OSNA assay appears to be a highly cost-effective method for providing rapid and reliable intra-operative assessment of sentinel lymph nodes.

Detection of lymph node metastases in human colorectal cancer by using 5-aminolevulinic acid-induced protoporphyrin IX fluorescence with spectral unmixing

Accurate evaluation of metastatic lymph nodes (LNs) is indispensable for adequate treatment of colorectal cancer (CRC) patients. Here, we demonstrate detection of metastases of human CRC in removed fresh LNs using 5-aminolevulinic acid (ALA)-induced protoporphyrin IX (PpIX) fluorescence. A spectral unmixing method was employed to reduce the overlap of collagen autofluorescence on PpIX fluorescence. A total of 17 surgery patients with advanced CRC were included in this study. After 5-ALA at a dose of 15 mg/kg of body weight was applied orally 2 h prior to surgery, 87 LNs were subjected to spectral fluorescence imaging and histopathological diagnosis, and statistical analysis was performed. No apparent side effect was observed to be associated with 5-ALA administration. The spectral unmixing fluorescence intensity of PpIX in metastatic LNs was 10.2-fold greater than that in nonmetastaic LNs. The receiver-operating-characteristic (ROC) analysis showed that the area under the curve (AUC) was calculated as 0.95. Our results show the potential of 5-ALA-induced PpIX fluorescence processed by spectral unmixing for detecting metastases in excised fresh LNs from patients with CRC, suggesting that this rapid and feasible method is applicable to gross evaluation of resected LN samples in pathology laboratories.

Sentinel and nonsentinel lymph node assessment using a combination of one-step nucleic acid amplification and conventional histological examination

BACKGROUND

Clinical significance of intraoperative sentinel lymph node (SLN) metastases detection using one-step nucleic acid amplification (OSNA) has not been thoroughly investigated. The aim of this study was to assess the usefulness of using a combination of OSNA and conventional histological examinations.

MATERIALS AND METHODS

We included 772 consecutive patients with clinical node-negative cTis-cT3 primary breast cancer who underwent SLN biopsy with intraoperative OSNA and multi-section histological examination at our institution. We estimated the concordance rate and compared SLN metastases detection rates between the two methods. We also compared non-SLN metastasis detection rate between patients who tested positive in OSNA and those who tested positive in histology.

RESULTS

Among 772 patients, SLN metastases were intraoperatively detected in 211 (26.4%) by either OSNA or histology, in 168 (21.8%) by OSNA, and in 150 (19.4%) by histology. The concordance rate between OSNA and histological examination was 89.2%, but only 123 (58.8%) patients tested positive in both OSNA and histology; 45 were positive in OSNA only and 43 were positive in histology only. SLN status as per both OSNA and histology was significantly correlated with the presence of non-SLN metastases and multivariate analysis-identified independent predictive factors of non-SLN metastases.

CONCLUSIONS

Intraoperative SLN metastases detection may be more accurate with a combination of OSNA and histological examination than with OSNA or histological examination alone. By using both methods, we can reduce the risk of false negative rate in SLN biopsy, and may prevent physicians from overlooking patients with non-SLN metastases.

Multiple Step-section Frozen Section sentinel lymph node biopsy--a review of 717 patients

Sentinel Lymph Node Biopsy (SLNB) is the standard of care for axillary staging in breast cancer. Multiple Step-section Frozen Section (MSFS) analysis is used in our institution for SLNB. This is performed intra-operatively by freezing sentinel lymph nodes to obtain multiple step-sections which are examined histologically for evidence of metastases. Patients whose sentinel lymph nodes contained macrometastases proceeded to an axillary node clearance during the same operation. 717 patients over a two and a half year period had MSFS analysis. With regards to macrometastases, MSFS analysis had a sensitivity of 93.8%, a specificity of 99.3%, a positive-predictive value of 97.4% and a negative-predictive value of 98.2%. MSFS analysis of sentinel lymph nodes is a safe and accurate procedure. It is a relatively cost-effective alternative to molecular technologies relying on DNA amplification and more accurate than standard frozen section or touch-prep cytology.

One-step nucleic acid amplification (OSNA) for intraoperative evaluation of sentinel lymph node status in breast cancer: a comparative study between CK19 protein expression and CK19 mRNA level in primary tumors and lymph node metastasis

The one-step nucleic acid amplification (OSNA) method is an increasingly used procedure for intraoperative analysis of sentinel lymph node (SLN) status in breast cancer patients. It measures cytokeratin19 (CK19) mRNA copy numbers in homogenized samples of SLN; CK19 has been chosen for identifying node metastasis because most breast cancers express this molecule. However, to avoid false-negative OSNA results, testing the preoperative needle core biopsy (NCB) of breast carcinomas for CK19 by immunohistochemistry (IHC) has been recommended. This procedure relies on the assumption that protein expression is strictly related to mRNA expression. We developed this study to evaluate if IHC gives similar result to the molecular assay. In a series of breast cancer patients with axillary metastasis, corresponding surgically resected tumor and metastatic lymph node specimens have been tested for CK19 protein by IHC and for CK19 mRNA by real-time PCR; furthermore, CK19 immunostaining has been performed in NCBs when available. Statistical analysis revealed that (1) the immunohistochemical evaluation of CK19 in NCB is a reliable test, reflecting protein expression in the whole tumor and in the metastatic lymph node; (2) there is no correlation between CK19 protein expression and CK19 RNA level neither within the primary breast cancer nor within the metastatic node; moreover, no correlation as well has been found between protein expression in NCB and mRNA level in metastatic lymph nodes. Thus, our results suggest that there is no evidence-based reason to stain every NCB for CK19 before performing OSNA in patients with breast cancer.

Using one-step nucleic acid amplification (OSNA) for intraoperative detection of lymph node metastasis in breast cancer patients avoids second surgery and accelerates initiation of adjuvant therapy

BACKGROUND

Sentinel lymph node (SLN) analysis is conventionally analyzed using immunohistochemistry and in the case of SLN involvement, justifies a second surgery for axillary lymph node (ALN) resection, thus delaying the initiation of adjuvant therapies.

PATIENTS AND METHODS

Three hundred and eighty-one patients with early stage breast cancer (BC) were considered in this retrospective study. SLNs were detected using combined radioisotope and dye detection. SLN involvement was analyzed using routine intraoperative One-Step Nucleic Acid Amplification (OSNA) assay, in 100 patients and compared with the conventional histopathology carried out previously in 281 patients.

RESULTS

Considering positive SLNs as '++' (CK19 mRNA copy number>5000), '+' (250 < CK19 mRNA copy number <5000) and positive by inhibition in the OSNA group and macro-, micrometastases and isolated tumor cells in the histopathology group, no difference in SLN involvement rate was found between the two groups with 29.0% and 29.9% of positive SLNs, respectively. Using OSNA intraoperatively, the mean time to process the SLN was 42 min allowing immediate ALN resection, reduced significantly (P < 0.01) the re-intervention rate (9% versus 39%) and significantly (P < 0.01) accelerated the initiation of adjuvant therapy (6.2 versus 8.4 weeks).

CONCLUSIONS

Using OSNA for intraoperative SLN analysis avoids second surgery for ALN resection in most patients and accelerates initiation of adjuvant therapy.

Quantitative molecular analysis of sentinel lymph node may be predictive of axillary node status in breast cancer classified by molecular subtypes

To determine the performance of intraoperative one-step nucleic acid amplification (OSNA) assay in detecting sentinel lymph node metastases compared to postoperative histology taking into account breast cancer molecular classification and to evaluate whether the level of cytokeratin 19 mRNA copy number may be useful in predicting the likelihood of a positive axillary lymph node dissection. OSNA assay was performed in a prospective series of 903 consecutive sentinel lymph nodes from 709 breast cancer patients using 2 alternate slices of each sentinel lymph node. The remaining 2 slices were investigated by histology. Cytokeratin 19 mRNA copy number, which distinguishes negative cases (<250 copies), micrometastases (+, ≥250≤5000 copies) and macrometastases (++, >5000 copies), was compared to axillary lymph node dissection status and to the biological tumor profile. Concordance between OSNA and histopathology was 95%, specificity 95% and sensitivity 93%. Multiple Corresponce Analysis and logistic regression evidenced that positive axillary lymph node dissection was significantly associated with a higher cytokeratin 19 mRNA copy number (>5000; p<0.0001), HER2 subtype (p = 0.007) and lymphovascular invasion (p<0.0001). Conversely, breast cancer patients with cytokeratin 19 mRNA copy number <2000 mostly presented a luminal subtype and a negative axillary lymph node dissection. We confirmed that OSNA assay can provide standardized and reproducible results and that it represents a fast and quantitative tool for intraoperative evaluation of sentinel lymph node. Omission of axillary lymph node dissection could be proposed in patients presenting a sentinel lymph node with a cytokeratin 19 mRNA copy number <2000 and a Luminal tumor phenotype.

The use of one step nucleic-acid amplification (OSNA) in clinical practice: a single-centre study

BACKGROUND

The development of intraoperative sentinel node biopsy (SLNB) analysis methods, such as One-Step Nucleic Acid Amplification (OSNA), has made single-stage procedures possible.

AIMS

We investigated the incidence of OSNA-detected lymph node positivity, comparing it to conventional histopathology, the incidence of non-SLNB node disease for the OSNA positive patients, and the breast re-operation rate, to assess the benefit from single-stage procedures.

METHODS

This was a single-centre series of 573 consecutive patients undergoing SLNB (173 histopathology and 400 OSNA).

RESULTS

OSNA-detected SLNB macrometastasis was similar to routine histopathology, with more micrometastasis detected (p < 0.001). Non-SLNB involvement in the OSNA group was similar to documented histopathological series. 27.6% of OSNA patients avoided further surgery because of OSNA. The median time for OSNA results was 42 min.

CONCLUSIONS

OSNA is an effective method for detecting SLNB-metastasis. It is easily used in clinical practice, providing reliable results and negating the need for a second axillary operation.

An optimal mRNA marker for OSNA (One-step nucleic acid amplification) based lymph node metastasis detection in colorectal cancer patients

BACKGROUND

We previously reported that the one-step nucleic acid amplification assay is effective for lymph node metastasis detection in breast cancer patients. This paper describes the identification of CK19 mRNA as an optimal marker and its cut-off value for use in the detection of one-step nucleic acid amplification-based lymph node metastasis in colorectal cancer patients.

METHODS

Candidate mRNA markers selected from the genome-wide expressed sequence tag database were evaluated by quantitative RT-PCR using a mixture of metastasis-positive and another mixture of metastasis-negative lymph nodes (n = 5 each), followed by quantitative RT-PCR using metastasis-positive and -negative lymph nodes (n = 10 each) from 20 patients. The one-step nucleic acid amplification assay for mRNA markers selected above was examined using 28 positive lymph nodes from 19 patients and 38 negative lymph nodes from the 11 pN0 patients.

RESULTS

Quantitative RT-PCR analyses of the 98 mRNAs selected from the genome-wide expressed sequence tag database and the subsequent quantitative RT-PCR analyses of the nine mRNAs selected above indicated that CK19 and CEA mRNAs have the highest capability for distinguishing between positive and negative lymph nodes. CK19, CEA and CK20 mRNAs were evaluated by the one-step nucleic acid amplification assay. An area under a receiver-operating-characteristic curve for CK19 mRNA (0.999) was slightly larger than that for CEA mRNA (0.946; P = 0.062) and significantly larger that than for CK20 mRNA (0.875; P = 0.006).

CONCLUSION

We found that CK19 mRNA has the best diagnostic performance and its cut-off value for discriminating positive from negative lymph nodes can be set in the range of 75-500 copies/µl with 96.4% sensitivity and 100% specificity.

Comparative study of one-step nucleic acid amplification assay, frozen section, and touch imprint cytology for intraoperative assessment of breast sentinel lymph node in Chinese patients

Conventional procedures for the intraoperative assessment of breast cancer sentinel lymph nodes (SLNs) are frozen section (FS) and touch imprint cytology (TIC). The one-step nucleic acid amplification (OSNA) assay is a novel molecular technique. The aim of this study was to evaluate the optimal approach by comparing OSNA assay, FS, and TIC. Five hundred and fifty-two consecutive patients were enroled from five study centers in China. The SLNs were cut into alternating 2 mm blocks. The odd blocks were tested by the OSNA assay intraoperatively, and the even ones were assessed by postoperative histology (four 4- to 6-μm-thick sections were taken every 200 μm per block). In addition, intraoperative histological assessments were carried out on the even blocks of 211 patients by FS and all blocks of 552 patients by TIC. Overall performance of the assay compared to postoperative histology was: accuracy 91.4%; sensitivity 83.7%; and specificity 92.9%. The sensitivity of the assay was higher than FS (211 patients, 77.6% vs 69.7%; not significant, P = 0.286) and was significantly higher than TIC (552 patients, 83.6% vs 76.2%; P = 0.044). When assessing nodes with micrometastases, the sensitivity of the assay was higher than FS (17 nodes, 47.1% vs 23.5%; not significant, P = 0.289) and was significantly higher than TIC (48 nodes, 62.5% vs 35.4%; P = 0.007). The study indicated that the OSNA assay is an accurate and rapid intraoperative assay for assessing breast SLNs and it can replace FS and TIC for application in general medical practice. The trial was registered as: OSNA assay China Registration Study.

CLINICAL TRIAL REGISTRATION NUMBER

China Breast Cancer Clinical Study Group 001c.

One-step nucleic acid amplification assay (OSNA) for sentinel lymph node biopsy

The one-step nucleic acid amplification assay (OSNA) has been developed for the intraoperative rapid detection of sentinel lymph node metastasis. Pooled analysis of recent studies comparing OSNA with pathology indicated that OSNA is as accurate as pathology (96.3 % concordance rate) and is useful for making the decision to omit axillary dissection for OSNA-negative patients (97.4 % negative predictive value). The advantage of OSNA over pathology is that the former allows the semiquantitative evaluation of total tumor volume in the node when a whole node is examined. OSNA is expected to be a powerful tool for the estimation of risk of non-sentinel lymph node metastasis and also patient prognosis, though further studies about this issue with larger numbers of patients is needed.

Sentinel lymph node analysis in breast cancer: contribution of one-step nucleic acid amplification (OSNA)

One-step nucleic acid amplification (OSNA, Sysmex, Kobe, Japan) offers an excellent opportunity for accurate exhaustive sentinel lymph node (SLN) examination in breast cancer patients. Calibrated with conventional postoperative histology, this molecular technique yields comparable results intraoperatively, expressed as micrometastasis, macrometastasis or no metastasis depending on the CK19 mRNA copy number amplified in SLN lysates. We applied OSNA to detect metastasis in 810 SLNs from 367 patients with early stage breast cancer. We compared the rate of OSNA-positive SLNs in patients with invasive breast cancer (< 2 cm) versus the rate observed in a historical cohort using conventional histological examination of SLNs. No significant difference was observed, the OSNA assay was positive in 24.4% of patients, compared with positive histology in 24.8% in the historical cohort if including patients with isolated tumour cell (ITC) and in 23.4% excluding them. Opportunities for optimised patient management using OSNA are discussed: intraoperative detection of OSNA-positive SLNs enables axillary lymph node dissection (ALND) during the same procedure; standard OSNA techniques enable the establishment of homogeneous groups based on examination of whole SLNs for valid comparisons between different centres.