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

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.

Omission of axillary lymph node dissection in breast cancer patients with micrometastasis or isolated tumor cells in sentinel lymph nodes: a 12-year experience in a tertiary breast unit

INTRODUCTION

After the IBCSG 23-01 trial, our breast center no longer performed axillary lymph node dissection (ALND) after detection of isolated tumor cells (ITC) or micrometastasis in the sentinel lymph nodes (SLN). A recent study suggested that up to half of the patients with micrometastasis in the SLN could benefit from ALND in terms of disease-free survival (DFS) and overall survival (OS).

METHODS

This retrospective, unicentric, study analyzed 261 consecutive cT1-3 cN0 breast cancer patients with ITC or micrometastasis in their SLN. Primary objective was comparison of ALND vs. SLN biopsy (SLNB) with regard to DFS and OS. Secondary objectives included analysis of factors associated with an increased rate of locoregional recurrence (LRR), distant metastasis (DM) and metachronous contralateral breast cancer (MCBC).

RESULTS

DFS events occurred in 19 patients (7.3%) and 14 patients died (5.4%). Median follow-up time was 78 months. 251 patients (96.2%) had micrometastasis in their SLN. There was no difference in the OS or DFS of ALND vs. SLNB patients. History of previous contralateral breast cancer and WBI were associated with an increased and decreased rate of LRR, respectively. Larger tumor size was associated with an increased rate of DM. Non-ductal histological types were associated with an increased rate of MCBC.

DISCUSSION

Avoiding ALND may be safe in pN1mi/pN0(i+) patients. Besides, we strongly encourage clinicians to develop their own follow-up protocols based on the best available evidence, to rapidly identify and treat breast cancer recurrence.

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.

The Diagnostic Accuracy of One-Step Nucleic Acid Amplification for Lymph Node Metastases of Papillary Thyroid Carcinoma： A Systematic Review and Meta-Analysis

BACKGROUND

One-step nucleic acid amplification (OSNA) analysis is a molecular diagnostic technique for lymph node metastases (LNMs) by quantifying cytokeratin 19(CK 19) mRNA. We aim to evaluate the intraoperative diagnostic accuracy of OSNA assay for LNMs of papillary thyroid carcinoma (PTC).

METHODS

PubMed, Embase, Cochrane Library, and Web of Science databases were searched to retrieve related literature. A meta-analysis was performed using STATA11.0, Meta-Disc 1.4 and RevMan 5.3.

RESULTS

This meta-analysis included six studies involving 987 lymph nodes from 194 patients. The pooled sensitivity, specificity, and area under the summary receiver-operating characteristic curve (AUC) of OSNA for detecting LNM were 0.88, 0.90, and 0.95, respectively.

CONCLUSION

OSNA assay is an accurate molecular diagnosis for intraoperative detection of lymph node metastasis in PTC.

Intraoperative Prediction Of Non-Sentinel Lymph Node Metastasis Based On The Molecular Assay In Breast Cancer Patients

Purpose

The aim of the study is to construct an intraoperative nomogram for the prediction of non-sentinel lymph node (NSLN) metastasis based on the one-step nucleic acid amplification assay in breast cancer patients.

Methods

A total of 552 patients were enrolled in the training study and 1090 patients were enrolled in the validation study. The nomogram was constructed based on the molecular assay with logistic multivariate regression analysis in the training study and was validated in the validation study.

Results

A novel nomogram model was constructed with the total tumor load, the clinical primary tumor size, the number of positive and negative sentinel lymph nodes. The area under the receiver operating characteristic curve (AUC) of the model was 0.842. The AUC of the model which was sensitive to discern the patients with the stage of pN1 and ≥pN2 was 0.861.

Conclusion

The nomogram model will help to guide the axillary management intraoperatively and precisely confirm the target region of radiotherapy postoperatively.

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.

One-step nucleic acid amplification: the possible value in assessing sentinel lymph node metastasis during mastectomy

Breast cancer is the most common cancer in women, worldwide, and 1,400 deaths per day are attributed to it. The success of national screening programs has seen breast cancers being diagnosed at an earlier stage. With conservative surgery to the breast demonstrating equivalent long-term outcomes, the last 10 years have seen a growing interest in the safety of less invasive management for the axilla in breast cancer patients. One-step nucleic acid amplification (OSNA) is a validated, reliable, and efficient tool in identifying micro- and macro-metastases intraoperatively. It is the most widely used intraoperative analysis tool within the United Kingdom, and is employed by over 320 units across Europe and Asia. Recent evidence from the AMAROS, IBCSG 23-01, and ACOSOG Z0011 trials has changed surgical practice in managing the axilla of patients with breast cancer. We propose a clinical algorithm demonstrating the role of OSNA as an intraoperative analysis tool in today's management of breast cancer as well as prospects for the future use of OSNA.

Comparison of CK-IHC assay on serial frozen sections, the OSNA assay, and in combination for intraoperative evaluation of SLN metastases in breast cancer

BACKGROUND

Intraoperative evaluations of sentinel lymph node (SLN) metastases are performed for providing appropriate and immediate axillary treatments in breast cancer patients who do not meet Z0011 criteria; however, standard intraoperative procedure has not yet been established.

METHODS

We consecutively performed intraoperative evaluation for SLN metastases using both a cytokeratin immunohistochemistry (CK-IHC) assay on serial frozen sections and a one-step nucleic acid amplification (OSNA) assay of the remaining whole node in patients with invasive breast cancer. In this article, we compared the intraoperative diagnostic ability of CK-IHC assay, the OSNA assay, and in combination.

RESULTS

Between August 2009 and May 2017, 1,103 SLNs from 499 consecutive clinically node-negative invasive breast cancers were intraoperatively evaluated for SLN metastases using an OSNA and CK-IHC assay. The detection rates of SLN metastases by the OSNA and CK-IHC assays and in combination were 11.8, 12.1, and 14.5%, respectively. The concordance rate between the intraoperative SLN findings of the OSNA and CK-IHC assays was 94.9% (95% confidence interval 93.6-96.2%). The false negative rate for the OSNA assay was 3.1% (30/973), including 3 (0.3%) macrometastases and 27 (2.8%) micrometastases, and for the CK-IHC assay was 2.7% (26/969), including 1 (0.1%) OSNA ++ and 25 (2.6%) OSNA +.

CONCLUSIONS

The CK-IHC assay and the OSNA assay have compatible diagnostic abilities in intraoperative evaluations for SLN metastases. The low incidence of false negative results with limited disease burden suggests that both assays can be reliable techniques for intraoperative diagnoses of SLN metastases in breast cancer patients.

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.

Validation of a Novel Diagnostic Kit Using the Semidry Dot-Blot Method to Detect Metastatic Lymph Nodes in Breast Cancer: Distinguishing Macrometastases From Nonmacrometastases

BACKGROUND

The semidry dot-blot method is a diagnostic procedure for detecting lymph node (LN) metastases using the presence of cytokeratin (CK) in lavage fluid from sectioned LNs. We evaluated 2 novel kits that use newly developed anti-CK-19 antibodies to diagnose LN metastases in breast cancer.

PATIENTS AND METHODS

We examined 159 LNs dissected that we sliced at 2-mm intervals and washed with phosphate-buffered saline. The suspended cells in the lavage were centrifuged and lysed to extract protein. This extracted protein was used with a low-power and a high-power kit to diagnose LN metastasis. Diagnoses on the basis of the kits were compared with pathological diagnoses.

RESULTS

Of the 159 LNs, 68 were assessed as positive and 91 as negative in permanent section examination. Sensitivity, specificity, and accuracy of the low-power kit for detecting LN metastases was 83.8%, 100%, and 93.1%, respectively. Those of the high-power kit were 92.6%, 92.3%, and 92.5%, respectively. Combining the low- and high-power kit results, those for distinguishing macrometastases were 94.5%, 95.2%, and 95.0%, respectively. Diagnosis was achieved in approximately 20 minutes, at a cost of less than $30 USD.

CONCLUSION

The kits were accurate, fast, and cost-effective in diagnosing LN metastases without the loss of LN tissue.

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.

Sentinel Lymph Node Frozen-Section Utilization Declines After Publication of American College of Surgeons Oncology Group Z0011 Trial Results With No Change in Subsequent Surgery for Axillary Lymph Node Dissection

OBJECTIVES

To evaluate use of sentinel lymph node (SLN) frozen section (FS) before and after publication of the Z0011 trial.

METHODS

We identified 116 pre-Z0011 and 134 post-Z0011 patients from 18 months before and after Z0011-initiated changes. Clinicopathologic features were assessed by chart review.

RESULTS

Post-Z0011 SLN FS use markedly declined when performed with breast-conserving therapy (BCT) (P < .0001), with SLN FS in 53 (73.6%) of 72 and 19 (25.0%) of 76 in pre- and post-Z0011 groups, respectively. There was post-Z0011 decline in axillary lymph node dissection (ALND) (P = .014) but no difference in later procedures for ALND. SLN positivity was associated with larger (≥1.6 cm) tumor size (P = .002). Nodal upstage was more frequent with invasive lobular (3/32; 9.4%) vs other invasive (2/188; 1.1%) subtypes.

CONCLUSIONS

Our findings support reduced need for SLN FS for BCT patients post-Z0011. However, those with specific clinicopathologic features may derive greater benefit from SLN FS.

The novel one-step nucleic acid amplification (OSNA) assay for the diagnosis of lymph node metastasis in patients with non-small cell lung cancer (NSCLC): Results of a multicenter prospective study

OBJECTIVES

The precise and rapid diagnosis of the presence or absence of lymph node (LN) metastasis is essential for deciding upon an appropriate therapeutic strategy for patients with non-small cell lung cancer (NSCLC). We conducted a prospective multicenter clinical trial in Japan to evaluate a rapid, automated and objective assay system, the one-step nucleic acid amplification (OSNA) assay (Sysmex Corp), which targets cytokeratin 19 mRNA, to detect LN metastasis of NSCLC.

MATERIALS AND METHODS

A total of 410 Lymph nodes (LNs) from 111 patients with clinical stage IB to IIIA NSCLC who underwent lung resection with LN dissection were included in this study. The LNs were divided into 4 blocks and examined by either the OSNA assay or a 3-level histological examination. The results of each method were compared and further analyses were performed for discordant cases. The primary endpoint was a concordance rate of more than 85% between the two methods.

RESULTS

The concordance rate between the two methods was 92.7% (95% CI, 89.7-95.0%), with a sensitivity of 79.7% (95% CI, 67.2-89.0%). Discordant results were observed in 30 LNs (5.8%), and were mainly due to a tissue allocation bias and/or contamination by CK19-expressing alveolar cells in LNs.

CONCLUSION

The OSNA assay gave a diagnosis that was as accurate as a 3-level histological examination, which is more detailed than a histological examination in routine clinical practice. The OSNA assay might be useful in intraoperative decision-making in personalized lung cancer surgery based on the LN status.

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.

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.

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.

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.