Sentinel node tumour burden quantified based on cytokeratin 19 mRNA copy number predicts non-sentinel node metastases in breast cancer: Molecular whole-node analysis of all removed nodes

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.

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.

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.

Intraoperative prediction of the two axillary lymph node macrometastases threshold in patients with breast cancer using a one-step nucleic acid cytokeratin-19 amplification assay

The aim of the present study was to assess the sensitivity, specificity and practicality of using a one-step nucleic acid amplification (OSNA) assay during breast cancer staging surgery to predict and discriminate between at least 2 involved nodes and more than 2 involved nodes and facilitate the decision to provide axillary conservation in the presence of a low total axillary node tumour burden. A total of 700 consecutive patients, not treated with neo-adjuvant chemotherapy, received intraoperative sentinel lymph node (SLN) analysis using OSNA for cT1-T3 cN0 invasive breast cancer. Patients with at least one macrometastasis on whole-node SLN analysis underwent axillary lymph node dissection (ALND). The total tumour load (TTL) of the macrometastatic SLN sample was compared with the non-sentinel lymph node (NSLN) status of the ALND specimen using routine histological assessment. In total, 122/683 patients (17.9%) were found to have an OSNA TTL indicative of macrometastasis. In addition, 45/122 (37%) patients had NSLN metastases on ALND with a total positive lymph node burden exceeding the American College of Surgeons Oncology Group Z0011 trial threshold of two macrometastatic nodes. The TTL negative predictive value was 0.975 [95% confidence interval (CI), 0.962-0.988]. The area under the curve for the receiver operating characteristic curve was 0.86 (95% CI, 0.81-0.91), indicating that SLN TTL was associated with the prediction (and partitioning) of total axillary disease burden. OSNA identifies a TTL threshold value where, in the presence of involved SLNs, ALND may be avoided. This technique offers objective confidence in adopting conservative management of the axilla in patients with SLN macrometastases.

A new molecular-based lymph node staging classification determines the prognosis of breast cancer patients

Background:

The one-step nucleic acid amplification (OSNA) assay is a novel molecular method that can detect metastasis in a whole lymph node based on cytokeratin 19 mRNA copy number. This cohort study aimed to establish an OSNA-based nodal staging (pN(mol)) classification for breast cancer.

Methods:

The cohort consisted of 1039 breast cancer patients who underwent sentinel node (SN) biopsy using the OSNA assay. Cutoff value of the SN tumour burden stratifying distant disease-free survival (DDFS) was determined, and predictive factors for DDFS and breast cancer-specific survival (BCSS) were investigated. pN(mol) classification of the SN status was defined as: pN0(mol)(sn), SN negative; pN1mi(mol)(sn), SN positive and tumour burden <cutoff-value; and pN1(mol)(sn), tumour burden ⩾cutoff-value. Median follow-up time; 68.3 months.

Results:

Cutoff value of the SN tumour burden was 2810 copies per μl. Of the 1039 patients, 798, 95, and 146 had pN0(mol)(sn), pN1mi(mol)(sn), and pN1(mol)(sn) status, respectively. Five-year DDFS and BCSS rates were lower for pN1(mol)(sn) patients than for pN1mi(mol)(sn) patients (87.7% vs 98.8%, P=0.001 and 93.1% vs 98.8%, P=0.044, respectively). Multivariate analyses revealed the pN(mol) classification was most significant predictor for DDFS and BCSS.

Conclusions:

The molecular-based pN classification determines the prognosis of breast cancer patients and could guide therapeutic decision making.

Cost and Budget Impact Analysis of an Accurate Intraoperative Sentinel Lymph Node Diagnosis for Breast Cancer Metastasis

BACKGROUND

Conventional intraoperative sentinel lymph node biopsy (SLNB) in breast cancer (BC) has limitations in establishing a definitive diagnosis of metastasis intraoperatively, leading to an unnecessary second operation. The one-step nucleic amplification assay (OSNA) provides accurate intraoperative diagnosis and avoids further testing. Only five articles have researched the cost and cost effectiveness of this diagnostic tool, although many hospitals have adopted it, and economic evaluation is needed for budget holders.

OBJECTIVE

We aimed to measure the budget impact in Japanese BC patients after the introduction of OSNA, and assess the certainty of the results.

METHODS

Budget impact analysis of OSNA on Japanese healthcare expenditure from 2015 to 2020. Local governments, society-managed health insurers, and Japan health insurance associations were the budget holders. In order to assess the cost gap between the gold standard (GS) and OSNA in intraoperative SLNB, a two-scenario comparative model that was structured using the clinical pathway of a BC patient group who received SLNB was applied. Clinical practice guidelines for BC were cited for cost estimation.

RESULTS

The total estimated cost of all BC patients diagnosed by GS was US$1,023,313,850. The budget impact of OSNA in total health expenditure was -US$24,413,153 (-US$346 per patient). Two-way sensitivity analysis between survival rate (SR) of the GS and OSNA was performed by illustrating a cost-saving threshold: y ≅ 1.14x - 0.16 in positive patients, and y ≅ 0.96x + 0.029 in negative patients (x = SR-GS, y = SR-OSNA). Base inputs of the variables in these formulas demonstrated a cost saving.

CONCLUSION

OSNA reduces healthcare costs, as confirmed by sensitivity analysis.

One-step nucleic acid amplification assay for intraoperative prediction of advanced axillary lymph node metastases in breast cancer patients with sentinel lymph node metastasis

The one-step nucleic acid amplification (OSNA) assay is used to semiquantitatively measure the cytokeratin (CK)19 mRNA copy numbers of each sentinel lymph node (SLN) in breast cancer patients. The aim of the present study was to evaluate whether the diagnosis of ≥4 LN metastases is possible using the OSNA assay intraoperatively. Between May, 2010 and December, 2014, a total of 134 patients who underwent axillary lymph node dissection (ALND) of positive SLNs were analyzed. The total tumor load (TTL) was defined as the total CK19 mRNA copies of all positive SLNs. The correlation between TTL and ≥4 LN metastases was evaluated. Of the 134 patients, 31 (23.1%) had ≥4 LN metastases. TTL ≥5.4×10⁴ copies/µl evaluated by receiver operator characteristic curve analysis was examined along with other clinicopathological variables. In the multivariate analysis, only TTL ≥5.4×10⁴ copies/µl was correlated with ≥4 LN metastases (odds ratio = 2.95, 95% confidence interval: 1.17-7.97, P=0.022). Therefore, TTL assessed by the OSNA assay has the potential to be a predictor of ≥4 LN metastases and it may be useful for the selection of patients with positive SLNs in whom ALND may be safely omitted.

Breast cancer metastasis burden in sentinel nodes analysed using one-step nucleic acid amplification predicts axillary nodal status

BACKGROUND

In breast cancer patients undergoing sentinel lymph node biopsy (SLNB) analysis using one-step nucleic acid amplification (OSNA), clarity is required as to the risk factors for non-sentinel lymph node (NSLN) involvement upon axillary lymph node dissection (ALND). This study aims to identify these factors, including categorising by extent of sentinel node positivity: solitary positive node (solitary), multiple nodes with some positive (multiple incomplete positive), or multiple nodes all of which are positive (multiple all positive).

METHODS

We conducted a cohort study using prospectively collected data on 856 SLNBs analysed using OSNA, from patients with cT1-3 clinically node-negative invasive breast cancer. ALND was performed for 289 positive SLNBs.

RESULTS

NSLN metastases were identified in 73 (25.3%) ALNDs. Significant factors for NSLN involvement on multivariate analysis were: SLNB macrometastases (cytokeratin-19 mRNA count >5000 copies/μl) (adj.OR = 3.01; 95% CI, 1.61-5.66; p = 0.0006), multiple all positive vs. multiple incomplete positive SLNB (adj.OR = 2.92; 95% CI, 1.38-6.19; p = 0.0050), and undergoing mastectomy (adj.OR = 1.89; 95% CI, 1.00-3.55; p = 0.0486). Amongst multiple incomplete positive SLNBs, an 8.8% NSLN risk was identified when only micrometastases were present.

CONCLUSION

Extent of sentinel lymph node positivity measured using OSNA predicts NSLN metastasis risk, aiding decisions surrounding axillary treatment.

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.

Keratins in health and disease

The cytoprotective keratins (K) compose the intermediate filaments of epithelial cells and their inherited and spontaneous mutations give rise to keratinopathies. For example, mutations in K1/K5/K10/K14 cause epidermal skin diseases whereas simple epithelial K8/K18/K19 variants predispose to development of several liver disorders. Due to their abundance, tissue- and context-specific expression, keratins constitute excellent diagnostic markers of both neoplastic and non-neoplastic diseases. During injury and in disease, keratin expression levels, cellular localization or posttranslational modifications are altered. Accumulating evidence suggests that these changes modulate multiple processes including cell migration, tumor growth/metastasis and development of infections. Therefore, our understanding of keratins is shifting from diagnostic markers to active disease modifiers.

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.

Tumoral load quantification of positive sentinel lymph nodes in breast cancer to predict more than two involved nodes

AIM

One-Step Nucleic Acid Amplification (OSNA) can detect isolated tumour loads in axillary lymph nodes of breast cancer patients. We investigated the predictability of the non-sentinel lymph node (SLN) metastatic involvement (MI) based on the OSNA SLN assessment in surgical invasive breast cancer.

METHODS

We studied surgical breast invasive carcinoma patients, not taking neoadjuvant chemotherapy, having SLN positive by OSNA and having received axillary lymphadenectomy. Age, basic histopathological, immunohistochemical, SLN biopsy and lymphadenectomy data were compared between patients with or without MI of more than 2 non-SLN in both univariate and multivariate analyses. The discriminating capacity of the multivariate model was characterized by the ROC AUC.

RESULTS

726 patients from 23 centers in Spain aged 55.3 ± 12.2 years were analysed. The univariate analysis comparing patients with or without MI of more than 2 non-SLN detected statistically significant differences in primary tumour size, multifocality, presence of lymphovascular infiltration, positive proliferation index with ki67, immunophenotype and logTTL (Tumour Total Load). The multivariate logistic analyses (OR (95% CI)) confirmed multifocality (2.16 (1.13-4.13), p = 0.019), lymphovascular infiltration (4.36 (2.43-7.82), p < 0.001) and logTTL (1.22 (1.10-1.35), p < 0.001) as independent predictors, and exhibit an AUC (95% CI) of 0.78 (0.72-0.83) with an overall fit (Hosmer-Lemeshow test) of 0.359. A change in the slope of both sensitivity and specificity is observed at about 10,000 copies/μL, without relevant changes in the Negative Predictive Values.

CONCLUSIONS

Using OSNA technique, the MI of more than 2 non-SLN can be reliably predicted.

Positive sentinel lymph node: the evolution of axillary surgery and intraoperative assessment of sentinel lymph nodes

SUMMARY 

Axillary lymph node dissection (ALND) has been the treatment for breast cancer in patients with sentinel lymph node (SLN) biopsy metastasis for prognostic information, local control and maybe for a small survival benefit. In recent years, clinicians have been questioning the need for axillary dissection in patients with positive SLN as the rate of axillary recurrences remains low when no ALND is performed in this group. Several variables incorporated in nomograms have been examined to predict axillary metastasis in patients with SLN metastasis and these nomograms have helped to determine which patients can spare the morbidity of the ALND. The combined multimodality in breast cancer treatments and the improvement in targeted therapies based in tumor biology have contributed to the low recurrence rates in early-stage breast cancer. As the multimodal treatment and the screening programs will improve, more patients with SLN metastasis will spare an ALND without compromising their oncologic outcome.

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.