Accurate staging of axillary lymph nodes from breast cancer patients using a novel molecular method

Molecular Detection of Lymph Node Metastases in Lung Cancer Patients Using the One-Step Nucleic Acid Amplification Method:Clinical Significance and Prognostic Value

The one-step nucleic acid amplification (OSNA) method allows for the quantitative evaluation of the tumor burden in resected lymph nodes (LNs) in patients with lung cancer. This technique enables to detect macro and micrometastases, facilitating the correct classification of patients for appropriate follow-up of the disease after surgery. Of 160 patients with resectable lung cancer whose LNs were examined by OSNA, H&E and CK19 IHC between July 2015 and December 2018, 110 patients with clinical stages from IA1 to IIIB were selected for follow-up. LN staging in lung cancer by pathological study led to understaging in 13.64% of the cases studied. OSNA allowed to quantify the tumor burden and establish a prognostic value. Patients with a total tumor load of ≥1650 cCP/uL were associated with a significantly increased likelihood of recurrence. Moreover, the survival of patients with <4405 cCP/uL was significantly higher than patients with ≥4405 cCP/uL. The OSNA assay is a rapid and accurate technique for quantifying the tumor burden in the LNs of lung cancer patients and OSNA quantitative data could allow to establish prognostic values for recurrence-free survival and overall survival in this type of malignancy.

A prediction model for early systemic recurrence in breast cancer using a molecular diagnostic analysis of sentinel lymph nodes: A large-scale, multicenter cohort study

BACKGROUND

The one-step nucleic acid amplification (OSNA) assay can quantify the cytokeratin 19 messenger RNA copy number as a proxy for sentinel lymph node (SN) metastasis in breast cancer. A large-scale, multicenter cohort study was performed to determine the prognostic value of the SN tumor burden based on a molecular readout and to establish a model for the prediction of early systemic recurrence in patients using the OSNA assay.

METHODS

SN biopsies from 4757 patients with breast cancer were analyzed with the OSNA assay. The patients were randomly assigned to the training or validation cohort at a ratio of 2:1. On the basis of the training cohort, the threshold SN tumor burden value for stratifying distant recurrence was determined with Youden's index; predictors of distant recurrence were investigated via multivariable analyses. Based on the selected predictors, a model for estimating 5-year distant recurrence-free survival was constructed, and predictive performance was measured with the validation cohort.

RESULTS

The prognostic cutoff value for the SN tumor burden was 1100 copies/μL. The following variables were significantly associated with distant recurrence and were used to construct the prediction model: SN tumor burden, age, pT classification, grade, progesterone receptor, adjuvant cytotoxic chemotherapy, and adjuvant anti-human epidermal growth factor receptor 2 therapy. The values for the area under the curve, sensitivity, specificity, and accuracy of the prediction model were 0.83, 63.4%, 81.7%, and 81.1%, respectively.

CONCLUSIONS

Using the OSNA assay, the molecular readout-based SN tumor burden is an independent prognostic factor for early breast cancer. This model accurately predicts early systemic recurrence and may facilitate decision-making related to treatment.

Prognostic impact and possible pathogenesis of lymph node metastasis in ductal carcinoma in situ of the breast

PURPOSE

Ductal carcinoma in situ (DCIS)-preinvasive breast cancer-with lymph node metastasis can clinically be treated as different stages: occult invasive cancer with true metastasis (T1N1) or pure DCIS with iatrogenic dissemination (TisN0). In this retrospective cohort study, we aimed to elucidate the prognostic impact and possible pathogenesis of nodal metastasis in DCIS to improve clinical management.

METHODS

Subjects were comprised of 427 patients with routine postoperative diagnosis of DCIS who underwent sentinel node (SN) biopsy using molecular whole-lymph-node analysis. Clinicopathological characteristics and prognosis were compared between SN-positive and -negative patients. Primary tumour tissues of SN-positive patients were exhaustively step-sectioned to detect occult invasions, and predictive factors for occult invasion were investigated. Median follow-up time was 73.6 months.

RESULTS

Of the 427 patients, 19 (4.4%) were SN-positive and 408 (95.6%) were SN-negative. More SN-positive patients received adjuvant systemic therapy than SN-negative patients (84.2% vs. 5.4%). Seven-year distant disease-free survivals were favourable for both cohorts (SN-positive, 100%; SN-negative, 99.7%). By examining 1421 slides, occult invasion was identified in 9 (47.4%) of the 19 SN-positive patients. Tumour burdens in SN and incidence of non-SN metastasis were similar between patients with and without occult invasion, and no predictive factor for occult invasion was found.

CONCLUSIONS

Node-positive DCIS has favourable prognosis with adjuvant systemic therapy. Half of the cases may be occult invasive cancer with true metastasis. In practical settings, clinicians may have to treat these tumours as node-positive small invasive cancers because it is difficult to predict the pathogenesis without exhaustive primary tumour sectioning.

Elucidation of inhibitory effects on metastatic sentinel lymph nodes of breast cancer during One-Step Nucleic Acid Amplification

One-step nucleic acid amplification (OSNA) is an established method for intraoperative diagnosis of breast cancer metastasis in sentinel lymph nodes, based on quantification of CK19 mRNA, specific to breast epithelial cells. Inhibitors interfere with the PCR amplification process of PCR. Thus, OSNA, based on gene amplification without RNA purification, might be impacted by numerous factors persisting in a sample, and thereby potentially acting as PCR inhibitors. However, neither the characteristics of breast cancers showing inhibitory effects during OSNA, nor any of the possible inhibitors, have as yet been identified. Inhibitory effects detected during OSNA in 72 metastatic lymph nodes and the patients' clinicopathological features were examined. Left-over OSNA samples were analyzed with mass spectrometry to identify proteins possibly acting as inhibitors. Most tumors showed inhibitory effects, though to varying degrees. Large tumor, young age and high tumor-infiltrating lymphocyte counts were related to stronger inhibitory effects. Proteome analysis revealed elevations in RPB9 protein and EIF2 signaling upregulation in samples showing strong inhibitory effects. Tumors showing strong inhibitory effects had clinically relevant characteristics, including large size and extensive tumor-infiltrating lymphocyte involvement. Identifying inhibitors in OSNA might provide new insights into breast cancer biology as well as advancing the current technology.

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.

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.

Intraoperative assessment of sentinel lymph node by one-step nucleic acid amplification in breast cancer patients after neoadjuvant treatment reduces the need for a second surgery for axillary lymph node dissection

PURPOSE

Sentinel lymph node (SLN) biopsy has been shown to be both accurate and feasible for women who receive neoadjuvant chemotherapy (NAC). Intraoperative assessment of SLN by frozen sections can produce false negative results. The aim of this study was to compare two different techniques of intraoperative assessment of SLN in breast cancer patients treated with NAC: frozen section (FS) and molecular assay (OSNA).

METHODS

A multicenter cohort of 320 consecutive breast cancer patients treated with NAC between 2010 and 2014 was analyzed. FS was performed intraoperatively in 166 patients (H&E cohort) and OSNA in 154 patients (OSNA cohort).

RESULTS

A mean of 2.15 SLNs by FS and 1.22 SLNs by OSNA was assessed (p = 0.03). SLN metastasis was found in 44 patients (26.5%) by FS and in 48 (31.2%) by OSNA (p = 0.4). There was no statistical significance in rates of macrometastasis (75%), micrometastasis (20.5%) or ITCs (4.5%) when assessed by FS compared to OSNA (52.3%, 36.3% and 11.4%, respectively) (p = 0.06). There were 10 patients in the H&E cohort with positive-SLN in the definitive pathology assessment with negative intraoperative FS. When OSNA and definitive pathology were compared, there were no differences in rates of macrometastasis (61.1%), micrometastasis (33.3%) nor ITCs (5.6%) (p = 0.5). Fifty-four patients in the H&E cohort and 44 in the OSNA cohort had ALND after positive-SLNs. ALND was performed in a second surgery in 10 patients (18.5%) in the H&E cohort for intraoperative FS false negative results, 90% being micrometastasis. 42 out of 44 patients (95.5%) in the OSNA cohort had an ALND in the same surgery (p = 0.03).

CONCLUSIONS

OSNA assay detects SLNs metastases as accurately as conventional pathology in the NAC setting. Intraoperative definitive assessment of the SLN by OSNA reduces the need for a second surgery for ALND in 18.5% of breast cancer patients with a positive-SLN after NAC.

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.

Incidence and prediction of invasive disease and nodal metastasis in preoperatively diagnosed ductal carcinoma in situ

For breast cancer patients with a preoperative diagnosis of ductal carcinoma in situ (DCIS), sentinel lymph node (SN) biopsy has been proposed as an axillary staging procedure in selected patients with a higher likelihood of having occult invasive lesions. With detailed histological examination of primary tumors and molecular whole-node analysis of SNs, we aimed to validate whether this selective application accurately identifies patients with SN metastasis. The subjects were 336 patients with a preoperative needle-biopsy diagnosis of DCIS who underwent SN biopsy using the one-step nucleic acid amplification assay in the period 2009–2011. The incidence and preoperative predictors of upstaging to invasive disease on final pathology and SN metastasis, and their correlation, were investigated. Of the 336 patients, 113 (33.6%) had invasive disease, and 6 (1.8%) and 17 (5.0%) had macro- and micrometastasis in axillary nodes respectively. Of the 113 patients with invasive disease, 4 (3.5%) and 9 (8.0%) had macro- and micrometastasis. Predictors of invasive disease included palpability, mammographic mass, and calcifications (spread >20 mm), and intraductal solid structure, but no predictor was found for SN metastasis. Therefore, even though occult invasive disease was found at final pathology, most of the patients had no metastasis or only micrometastasis in axillary nodes. Predictors of invasive disease and SN metastasis were not completely consistent, so the selective SN biopsy for patients with a higher risk of invasive disease may not accurately identify those with SN metastasis. More accurate application of SN biopsy is required for patients with a preoperative diagnosis of DCIS.

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.

Molecular detection of lymph node metastasis in breast cancer patients treated with preoperative systemic chemotherapy: a prospective multicentre trial using the one-step nucleic acid amplification assay

BACKGROUND

For patients with breast cancer treated with preoperative chemotherapy, residual tumour burden in lymph nodes is the strongest prognostic factor. However, conventional pathological examination has limitations that hinder the accurate and reproducible measurement. The one-step nucleic acid amplification (OSNA) assay is a novel molecular method for detecting nodal metastasis. In this prospective multicentre trial, we assessed the performance of the OSNA assay in detecting nodal metastasis after chemotherapy.

METHODS

In total, 302 lymph nodes from 80 breast cancer patients who underwent axillary dissection after chemotherapy were analysed. Each node was cut into two or four slices. One piece or alternate pieces were evaluated by pathology, and the other(s) were examined using the OSNA assay. The results of the two methods were compared. Stromal fibrosis, histiocytic aggregates, and degenerated cancer cells were regarded as chemotherapy-induced histological changes.

RESULTS

The overall accuracy, sensitivity, and specificity of the OSNA assay compared with the reference pathology were 91.1%, 88.3%, and 91.7%, respectively. Of the 302 lymph nodes, 66 (21.9%) exhibited chemotherapy-induced histology. For these nodes, the accuracy, sensitivity, and specificity were 90.9%, 88.9%, and 93.3%, respectively.

CONCLUSION

The OSNA assay can detect the residual tumour burden as accurately as conventional pathology, although chemotherapy-induced histological changes are present.

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.

Prediction of non-sentinel lymph node metastasis in early breast cancer by assessing total tumoral load in the sentinel lymph node by molecular assay

INTRODUCTION

The one-step nucleic acid amplification (OSNA) is a molecular procedure that yields a semiquantitative result for detection of nodal metastasis. Size of metastasis in the sentinel lymph node (SLN) by conventional histology has been described as a predictive factor for additional axillary metastasis. The objective of this study is to quantify intraoperatively the total tumoral load (TTL) in the positive SLNs assessed by OSNA and to determine whether this TTL predicts non-SLN metastasis in patients with clinically node negative early stage breast cancer.

METHODS

306 patients with cT1-3N0 invasive breast cancer who had undergone intraoperative SLN evaluation by OSNA were included. TTL was defined as the addition of CK19 mRNA copies of each positive SLN (copies/μL).

RESULTS

TTL was a predictive factor of additional non-SLN metastasis in the complete axillary lymph node dissection (cALND) (OR, 1.67; 95% CI, 1.18-2.35). In the multivariate analysis, the TTL was a predictor of non-SLN metastasis in HR positive patients (OR, 1.69; 95% CI, 1.19-2.41). In our cohort of patients, with a TTL ≤1.2 × 10(5) copies/μL, there was a specificity of 85.3% and negative predictive value (NPV) of 80%. If we consider only the HR positive patients, with a TTL ≤5 × 10(5) copies/μL there was a specificity of 86.7% and NPV of 83.7%.

CONCLUSIONS

TTL assessed by OSNA assay predicts for additional non-SLN metastasis and this intraoperative tool can help guiding decisions on performing a cALND in breast cancer patients.

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.

Detection of occult invasion in ductal carcinoma in situ of the breast with sentinel node metastasis

By definition, ductal carcinoma in situ (DCIS) - pre-invasive breast cancer - does not metastasize to the lymph nodes. However, since the introduction of molecular whole-node analysis using the one-step nucleic acid amplification assay for sentinel node (SN) biopsies, the number of patients with DCIS and SN metastasis has increased. The pathogenesis and clinical management of DCIS with SN metastasis remain controversial. In this case-control study, in order to elucidate the pathogenesis of SN metastasis in DCIS, we compared occult invasions between the SN-positive and SN-negative DCIS and investigated predictive factors of occult invasion. The subjects were 24 patients selected from 285 patients with a routine postoperative diagnosis of DCIS who had undergone SN biopsy using the one-step nucleic acid amplification whole-node assay between 2009 and 2011. Of these 24 patients, 12 were SN-positive, and 12 were SN-negative. The 12 SN-negative patients make up the control group and were selected from the 273 SN-negative patients based on patient characteristics. All paraffin blocks of the primary tumor from each patient were step-sectioned with 500-μm intervals until the block was exhausted and histopathologically examined. We analyzed 1830 step-sectioned slides and found occult invasions were more frequent in the SN-positive group (7/12, 58.3%) than in the SN-negative group (3/12, 25.0%). All occult invasions were <5 mm. There was no correlation between occult invasion and SN tumor burden, non-SN metastasis, or patient characteristics. Our results suggest true metastasis from occult invasion may be a potent pathogenesis indicating nodal metastasis in postoperatively diagnosed DCIS. Patient follow-up is required to elucidate the prognostic impact of nodal metastasis and occult invasion.

Incidence and possible pathogenesis of sentinel node micrometastases in ductal carcinoma in situ of the breast detected using molecular whole lymph node assay

Background:

The pathogenesis of lymph node metastases in preinvasive breast cancer – ductal carcinoma in situ (DCIS) – remains controversial. The one-step nucleic acid amplification (OSNA) assay is a novel molecular method that can assess a whole node and detect clinically relevant metastases. In this retrospective cohort study, we determined the performance of the OSNA assay in DCIS and the pathogenesis of node-positive DCIS.

Methods:

The subjects consisted of 623 patients with DCIS who underwent sentinel lymph node (SN) biopsy. Of these, 2-mm-sectioned nodes were examined using frozen-section (FS) histology in 338 patients between 2007 and 2009, while 285 underwent OSNA whole node assays between 2009 and 2011. The SN-positivity rate was compared between cohorts, and the characteristics of OSNA-positive DCIS were investigated.

Results:

The OSNA detected more cases of SN metastases than FS histology (12 out of 285, 4.2% vs 1 out of 338, 0.3%). Most of the metastases were micrometastases. The characteristics of high-risk DCIS (i.e., mass formation, size, grade, and comedo) and preoperative breast biopsy (i.e., methods or time to surgery) were not valid for OSNA assay–positive DCIS.

Conclusion:

The OSNA detects more SN metastases in DCIS than FS histology. Further examination of the primary tumours and follow-up of node-positive DCIS are needed to elucidate the pathogenesis.