The diagnostic value of one-step nucleic acid amplification (OSNA) for sentinel lymph nodes in colon cancer patients

Sentinel Lymph Node Mapping in Lung Cancer: A Pilot Study for the Detection of Micrometastases in Stage I Non-Small Cell Lung Cancer

Lymphadenectomy represents a fundamental step in the staging and treatment of non-small cell lung cancer (NSCLC). To date, the extension of lymphadenectomy in early-stage NSCLC is a debated topic due to its possible complications. The detection of sentinel lymph nodes (SLNs) is a strategy that can improve the selection of patients in which a more extended lymphadenectomy is necessary. This pilot study aimed to refine lymph nodal staging in early-stage NSCLC patients who underwent robotic lung resection through the application of innovative intraoperative sentinel lymph node (SLN) identification and the pathological evaluation using one-step nucleic acid amplification (OSNA). Clinical N0 NSCLC patients planning to undergo robotic lung resection were selected. The day before surgery, all patients underwent radionuclide computed tomography (CT)-guided marking of the primary lung lesion and subsequently Single Photon Emission Computed Tomography (SPECT) to identify tracer migration and, consequently, the area with higher radioactivity. On the day of surgery, the lymph nodal radioactivity was detected intraoperatively using a gamma camera. SLN was defined as the lymph node with the highest numerical value of radioactivity. The OSNA amplification, detecting the mRNA of CK19, was used for the detection of nodal metastases in the lymph nodes, including SLN. From March to July 2021, a total of 8 patients (3 female; 5 male), with a mean age of 66 years (range 48-77), were enrolled in the study. No complications relating to the CT-guided marking or preoperative SPECT were found. An average of 5.3 lymph nodal stations were examined (range 2-8). N2 positivity was found in 3 out of 8 patients (37.5%). Consequently, pathological examination of lymph nodes with OSNA resulted in three upstages from the clinical IB stage to pathological IIIA stage. Moreover, in 1 patient (18%) with nodal upstaging, a positive node was intraoperatively identified as SLN. Comparing this protocol to the usual practice, no difference was found in terms of the operating time, conversion rate, and complication rate. Our preliminary experience suggests that sentinel lymph node detection, in association with the accurate pathological staging of cN0 patients achieved using OSNA, is safe and effective in the identification of metastasis, which is usually undetected by standard diagnostic methods.

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.

Non-exposed endoscopic wall-inversion surgery with one-step nucleic acid amplification for early gastrointestinal tumors: Personal experience and literature review

BACKGROUND

Laparoscopic and endoscopic cooperative surgery is a safe, organ-sparing surgery that achieves full-thickness resection with adequate margins. Recent studies have demonstrated the safety and efficacy of these procedures. However, these techniques are limited by the exposure of the tumor and mucosa to the peritoneal cavity, which could lead to viable cancer cell seeding and the spillage of gastric juice or enteric liquids into the peritoneal cavity. Non-exposed endoscopic wall-inversion surgery (NEWS) is highly accurate in determining the resection margins to prevent intraperitoneal contamination because the tumor is inverted into the visceral lumen instead of the peritoneal cavity. Accurate intraoperative assessment of the nodal status could allow stratification of the extent of resection. One-step nucleic acid amplification (OSNA) can provide a rapid method of evaluating nodal tissue, whilst near-infrared laparoscopy together with indocyanine green can identify relevant nodal tissue intraoperatively.

AIM

To determine the safety and feasibility of NEWS in early gastric and colon cancers and of adding rapid intraoperative lymph node (LN) assessment with OSNA.

METHODS

The patient-based experiential portion of our investigations was conducted at the General and Oncological Surgery Unit of the St. Giuseppe Moscati Hospital (Avellino, Italy). Patients with early-stage gastric or colon cancer (diagnosed via endoscopy, endoscopic ultrasound, and computed tomography) were included. All lesions were treated by NEWS procedure with intraoperative OSNA assay between January 2022 and October 2022. LNs were examined intraoperatively with OSNA and postoperatively with conventional histology. We analyzed patient demographics, lesion features, histopathological diagnoses, R0 resection (negative margins) status, adverse events, and follow-up results. Data were collected prospectively and analyzed retrospectively.

RESULTS

A total of 10 patients (5 males and 5 females) with an average age of 70.4 ± 4.5 years (range: 62-78 years) were enrolled in this study. Five patients were diagnosed with gastric cancer. The remaining 5 patients were diagnosed with early-stage colon cancer. The mean tumor diameter was 23.8 ± 11.6 mm (range: 15-36 mm). The NEWS procedure was successful in all cases. The mean procedure time was 111.5 ± 10.7 min (range: 80-145 min). The OSNA assay revealed no LN metastases in any patients. Histologically complete resection (R0) was achieved in 9 patients (90.0%). There was no recurrence during the follow-up period.

CONCLUSION

NEWS combined with sentinel LN biopsy and OSNA assay is an effective and safe technique for the removal of selected early gastric and colon cancers in which it is not possible to adopt conventional endoscopic resection techniques. This procedure allows clinicians to acquire additional information on the LN status intraoperatively.

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.

Role of one-step nucleic acid amplification in colorectal cancer lymph node metastases detection

Current histopathological staging procedures in colorectal cancer (CRC) depend on midline division of the lymph nodes (LNs) with one section of hematoxylin and eosin staining. Cancer cells outside this transection line may be missed, which could lead to understaging of Union for International Cancer Control Stage II high-risk patients. The one-step nucleic acid amplification (OSNA) assay has emerged as a rapid molecular diagnostic tool for LN metastases detection. It is a molecular technique that can analyze the entire LN tissue using a reverse-transcriptase loop-mediated isothermal amplification reaction to detect tumor-specific cytokeratin 19 mRNA. Our findings suggest that the OSNA assay has a high diagnostic accuracy in detecting metastatic LNs in CRC and a high negative predictive value. OSNA is a standardized, observer-independent technique, which may lead to more accurate staging. It has been suggested that in stage II CRC, the upstaging can reach 25% and these patients can access postoperative adjuvant chemotherapy. Moreover, intraoperative OSNA sentinel node evaluation may allow early CRC to be treated with organ-preserving surgery, while in more advanced-stage disease, a tailored lymphadenectomy can be performed considering the presence of aberrant lymphatic drainage and skip metastases.

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.

Real-time fluorescence image-guided gastrointestinal oncologic surgery: Towards a new era

Technological improvements are crucial in the evolution of surgery. Real-time fluorescence-guided surgery (FGS) has spread worldwide, mainly because of its usefulness during the intraoperative decision-making processes. The success of any gastrointestinal oncologic resection is based on the anatomical identification of the primary tumor and its regional lymph nodes. FGS allows also to evaluate the blood perfusion at the gastrointestinal stumps after colorectal or esophageal resections. Therefore, a reduction on the anastomotic leak rates has been postulated as one of the foreseeable benefits provided by the use of FGS in these procedures. Although the use of fluorescence in lymph node detection was initially described in breast cancer surgery, the technique is currently applied in gastric or splenic flexure cancers, as they both present complex and variable lymphatic drainages. FGS allows also to perform intraoperative lymphograms or sentinel lymph node biopsies. New applications of FGS are being developed to assist in the detection of peritoneal metastases or in the evaluation of the tumor resection margins. The present review aims to provide a general overview of the current status of real-time FGS in gastrointestinal oncologic surgery. We put a special focus on the different applications of FGS, discussing the main findings and limitations found in the contemporary literature and also the promising near future applications.

Feasibility of Pooled One-Step Nucleic Acid Amplification for Molecular Staging of Pathologically Node-Negative Colon Cancer: A Prospective Multicenter Study

BACKGROUND

Although conventional one-step nucleic acid amplification (OSNA) is a useful molecular-staging method, its complexity hinders its use in clinical practice. A pooled approach for OSNA (pOSNA) has been evaluated for its feasibility in pathologically node-negative colon cancer (pNNCC) for molecular staging of lymph node metastasis in clinical practice.

METHODS

Subjects were patients diagnosed with clinical stage II-IIIA colon cancer between January 2017 and September 2018. pOSNA involved harvesting pericolic lymph nodes from fresh surgical specimens, cutting them in half, placing 50% of the nodes in a single test tube, and performing the OSNA assay. The remaining halved pericolic, intermediate, and main lymph nodes were submitted for histopathologic examination, with metastasis determined by hematoxylin and eosin staining of a cut surface of each node.

RESULTS

Of the 98 enrolled patients, 92 formed the analysis set. The mean number of harvested lymph nodes per case was 24.3 (range 5-66) and the mean number of lymph nodes used for pOSNA analysis was 6.9 (range 1-35). The concordance rate, sensitivity, and specificity between methods were 89.1%, 84.6% (95% confidence interval [CI] 0.80-0.91), and 90.9% (95% CI 0.88-0.94), respectively. The pOSNA upstaging rate for node-negative patients was 9.1% (6/66), and pOSNA returned false-negative results in 15.4% of node-positive cases (4/26).

CONCLUSIONS

pOSNA demonstrated an upstaging rate for pNNCC equivalent to that in previous studies, suggesting its feasibility for molecular staging of pNNCC in clinical practice.

The impact of molecular profile on the lymphatic spread pattern in stage III colon cancer

The anatomical spread of lymph node (LN) metastasis is of practical importance in the surgical management of colon cancer (CC). We examined the effect of KRAS, BRAF, and microsatellite instability (MSI) on LN count and anatomical spread pattern in stage III CC. We determined KRAS, BRAF, and MSI status from stage III CC patients. Biomarker status was correlated with LN count and anatomical spread pattern, which was classified as sequential or skipped. Relapse-free survival (RFS) was estimated using Kaplan-Meier method, and correlations were assessed using log-rank and Cox regression analyses. We analyzed 369 stage III CC patients. The proportion of KRAS mutant (mt), BRAF mt, and MSI-high (H) were 44.2% (163/344), 6.8% (25/344), and 6.8% (25/344), respectively. The mean number of metastatic LN was higher in microsatellite-stable (MSS) compared with MSI patients (3.5 vs. 2.7, P = .0406), although no differences were observed in accordance with KRAS or BRAF status. Interestingly, patients with BRAF mt and MSI-H were less likely to harbor skipped metastatic LN (9.3% vs 20% and 4% vs 10.5% compared with BRAF wild-type (wt) and MSS, respectively), but KRAS status did not predict anatomical spread pattern. Patients with KRAS wt and MSI-H showed superior RFS compared with KRAS mt and MSS patients, respectively, whereas BRAF status did not affect RFS. Differences exist in the anatomical pattern of invaded LN in accordance with the molecular status of stage III CC. Patients with MSI-H CC have less invaded and skipped LN, suggesting that a tailored surgical approach is possible.

Molecular Lymph Node Staging with One-Step Nucleic Acid Amplification and its Prognostic Value for Patients with Colon Cancer: The First Follow-up Study

Background

Molecular lymph node workup with one-step nucleic acid amplification (OSNA) is a validated diagnostic adjunct in breast cancer and also appealing for colon cancer (CC) staging. This study, for the first time, evaluates the prognostic value of OSNA in CC.

Patients and methods

The retrospective study includes patients with stage I-III CC from three centres. Lymph nodes were investigated with haematoxylin and eosin (H&E) and with OSNA, applying a 250 copies/μL threshold of CK19 mRNA. Diagnostic value of H&E and OSNA was assessed by survival analysis, sensitivity, specificity and time-dependent receiver operating characteristic curves.

Results

Eighty-seven patients were included [mean follow-up 53.4 months (± 24.9)]. Disease recurrence occurred in 16.1% after 19.8 months (± 12.3). Staging with H&E independently predicted worse cancer-specific survival in multivariate analysis (HR = 10.77, 95% CI 1.07–108.7, p = 0.019) but not OSNA (HR = 3.08, 95% CI 0.26–36.07, p = 0.197). With cancer-specific death or recurrence as gold standard, H&E sensitivity was 46.7% (95% CI 21.3–73.4%) and specificity 84.7% (95% CI 74.3–92.1%). OSNA sensitivity and specificity were 60.0% (95% CI 32.3–83.7%) and 75.0% (95% CI 63.4–84.5%), respectively.

Conclusions

In patients with CC, OSNA does not add relevant prognostic value to conventional H&E contrasting findings in other cancers. Further studies should assess lower thresholds for OSNA (< 250 copies/μL).

The advantage of one-step nucleic acid amplification for the diagnosis of lymph node metastasis in colorectal cancer patients

Generally, the postoperative examination of lymph nodes (LNs) is based on a microscopic examination of one hematoxylin and eosin (HE)-stained slide; however, an examination of only one part of the LN might lead to incorrect staging of the tumor due to tissue allocation bias. Although multilevel sectioning and the use of immunohistochemistry (IHC) have improved the detection of micrometastases in LNs, this approach is laborious, time-consuming, and costly. A novel molecular technique for the detection of LN metastases of tumors, called one-step nucleic acid amplification (OSNA), is a rapid and semi-quantitative examination quantifying the number of cytokeratin 19 (CK-19) mRNA copies derived from a tumor. OSNA is already in clinical use for the diagnosis of LN metastasis in breast cancer patients; however, the use of OSNA is under investigation with promising results for colorectal cancer (CRC). The present review assessed recent studies on OSNA vs a histopathological examination and its implications for CRC staging and treatment. A total of 16 studies of OSNA in CRC yielded by a PubMed search were reviewed. Among them, seven studies evaluating the diagnostic performance revealed that OSNA had a high specificity (96.8%), high concordance rate (96.0%), and negative predictive value (98.6%) in a pooled assessment. In addition, four studies examining the utility of OSNA in sentinel LNs (SLNs) and two studies focusing on upstaging in pathologically node-negative CRC patients were also reviewed. Multicenter prospective studies with a large cohort of CRC patients are warranted to reveal the benefits of OSNA in the future.

The evolving role of one-step nucleic acid amplification (OSNA) for the intra-operative detection of lymph node metastases: A diagnostic accuracy meta-analysis

BACKGROUND

One Step Nucleic Acid Amplification (OSNA) assay has recently emerged as a rapid molecular diagnostic tool for the detection of lymph node (LN) metastases. It is a molecular technique that analyses the entire LN tissue using a reverse-transcriptase loop-mediated isothermal amplification reaction to detect tumour specific cytoceratin 19 mRNA.

AIM

To ascertain the diagnostic accuracy of OSNA assay in detecting LN metastases amongst different types of malignancy.

DESIGN

We systematically searched MEDLINE, SCOPUS, ClinicalTrials.gov, and Cochrane Database, from inception up to August 2020. Quality assessment was performed using the Modified Quality Assessment of Diagnostic Accuracy Studies (QUADAS-2). We calculated pooled diagnostic indices using the random-effects model. Meta-regression and sub-group analyses were performed to address heterogeneity.

RESULTS

31 studies were included in this meta-analysis, including four different types of cancer. The risk of bias and the overall quality of included studies was moderate to high. There was no evidence of publication bias. The pooled diagnostic odds ratio (DOR) for detecting LN metastases in gynaecological, head & neck/thyroid, gastrointestinal and lung cancer were 100.38, 76.17, 275.14, and 305.84, respectively.

CONCLUSIONS

Our findings suggest that OSNA assay had a high diagnostic accuracy in detecting metastatic LNs in different types of malignancy. This evidence is constrained by the limited studies available for few tumour types and the rather high heterogeneity for few outcomes.

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.

Node negative colorectal cancer patients: assesment of high-risk features on recurrence

BACKGROUND

The introduction of population-based screening programs for colorectal cancer (CRC) results in less patients with advanced disease. There is an increase in the amount of node negative CRC, which makes adequate risk stratification for this particular group of patients necessary. The addition of more risk factors to the conventional histological high-risk factors is investigated in this retrospective study.

PATIENTS AND METHODS

A cohort of 227 node negative (stage I and II) CRC patients who were not treated with adjuvant chemotherapy were selected from two previously conducted cohort studies. Detailed histopathological examination was performed by two independent observers and molecular background (BRAF/RAS mutations, microsatellite status (MSI)) was studied. Univariate analyses were used to analyse differences in histological and mutational characteristics between patients with and without recurrence. P-values below 0.05 were considered statistically significant.

RESULTS

Poorly differentiated histology (p:0.002), BRAF mutation (p:0.002) and MSI status (p:0.006) were found significant relevant risk factors that were related to recurrent disease. Poorly differentiated histology was associated with intermediate/high tumor budding (TB) (p:0.001), a BRAF mutation (p:0.001) and MSI status (p:0.001). A combination of all three features (poorly differentiated histology, BRAF and MSI) was more often present in the recurrence group.

CONCLUSIONS

Recurrence in node negative CRC patients could be better predicted when molecular features such as, BRAF mutation and MSI status are incorporated into a model with poorly differentiated CRC. Therefore, these features might help in the selection of patients who possibly will benefit from adjuvant treatment.

Lymph Node Positivity in One-Step Nucleic Acid Amplification is a Prognostic Factor for Postoperative Cancer Recurrence in Patients with Stage II Colorectal Cancer: A Prospective, Multicenter Study

Background

For colorectal cancer (CRC) patients, the standard histological lymph node (LN) evaluation has low sensitivity. Our previously developed one-step nucleic acid amplification (OSNA™) assay measures cytokeratin 19 gene expression in whole LNs. We recently showed that 17.6% of pN0 stage II CRC patients were OSNA positive, suggesting a correlation between OSNA results and disease recurrence. This multicenter, prospective study investigateed the prognostic value of the OSNA assay for pStage II CRC patients.

Methods

We examined 204 CRC patients who were preoperatively diagnosed as cN0 and cN1 and surgically treated at 11 medical institutions across Japan. Nine patients were excluded, and 195 patients (Stage I: n = 50, Stage II: n = 70, Stage III: n = 75) were examined. All LNs, harvested from patients, were examined histopathologically using one-slice hematoxylin–eosin staining. Furthermore, half of the LNs was examined by the OSNA assay. Patients were classified according to the UICC staging criteria and OSNA results, and the 3-year, disease-free survival (DFS) of each cohort was analyzed.

Results

Average 21.2 LNs/patient were subject to pathological examination. Approximately half of all harvested LNs (average, 9.4 LNs/patient) were suitable for the OSNA assay. Significantly lower 3-year DFS rates were observed in pStage (pathological Stage) II OSNA-positive patients than in OSNA-negative patients (p = 0.005). Among all assessed clinical and pathological parameters, only the OSNA result significantly affected 3-year DFS rates in pStage II CRC patients (p = 0.027).

Conclusions

This study shows that OSNA positivity is a risk factor for recurrence of the patients with pStage II CRC.

Electronic supplementary material

The online version of this article (10.1245/s10434-019-07971-y) contains supplementary material, which is available to authorized users.

Budget Impact Analysis of Molecular Lymph Node Staging Versus Conventional Histopathology Staging in Colorectal Carcinoma

BACKGROUND

The presence of lymph node (LN) metastasis is a critical prognostic factor in colorectal cancer (CRC) patients and is also an indicator for adjuvant chemotherapy. The gold standard (GS) technique for LN diagnosis and staging is based on the analysis of haematoxylin and eosin (H&E)-stained slides, but its sensitivity is low. As a result, patients may not be properly diagnosed and some may have local recurrence or distant metastases after curative-intent surgery. Many of these diagnostic and treatment problems could be avoided if the one-step nucleic acid amplification assay (OSNA) was used rather than the GS technique. OSNA is a fast, automated, standardised, highly sensitive, quantitative technique for detecting LN metastases.

OBJECTIVES

The aim of this study was to assess the budget impact of introducing OSNA LN analysis in early-stage CRC patients in the Spanish National Health System (NHS).

METHODS

A budget impact analysis comparing two scenarios (GS vs. OSNA) was developed within the Spanish NHS framework over a 3-year time frame (2017-2019). The patient population consisted of newly diagnosed CRC patients undergoing surgical treatment, and the following costs were included: initial surgery, pathological diagnosis, staging, follow-up expenses, systemic treatment and surgery after recurrence. One- and two-way sensitivity analyses were performed.

RESULTS

Using OSNA instead of the GS would have saved €1,509,182, €6,854,501 and €10,814,082 during the first, second and third years of the analysis, respectively, because patients incur additional costs in later years, leading to savings of more than €19 million for the NHS over the 3-year time horizon.

CONCLUSIONS

Introducing OSNA in CRC LN analysis may represent not only an economic benefit for the NHS but also a clinical benefit for CRC patients since a more accurate staging could be performed, thus avoiding unnecessary treatments.

The diagnostic value of one step nucleic acid amplification (OSNA) in differentiating lymph node metastasis of tumors: A systematic review and meta-analysis

BACKGROUND

The aim of this study was clarify the diagnostic accuracy of one step nucleic acid amplification (OSNA) for differentiating metastatic lymph nodes from non-metastatic ones in patients with tumors (not including breast cancer).

METHODS

A systematic literature search for original diagnostic studies was performed in PubMed. Findings were pooled by using combined effect models and hierarchic summary receiver operating characteristic curve models. Meta-regression analysis and threshold effect evaluating were performed to explore the sources of heterogeneity affected classification accuracy.

RESULTS

19 studies (803 positive and 4594 negative lymph nodes) were analyzed, including 4 different tumor types (head and neck cancers, gastrointestinal cancers, lung cancer and gynecological malignancies). In the studies of head and neck cancers the pooled sensitivity, specificity and area under the curve (AUC) of the OSNA method were 0.85(0.79-0.89), 0.96(0.92-0.98) and 0.91 (0.88-0.93), respectively. Similarly, the corresponding values in the studies of gastrointestinal cancers were 0.90(0.85-0.94), 0.96(0.94-0.98) and 0.97 (0.96-0.99), respectively. Because of limited number of studies, the other two tumor types were inestimable in the subsequent meta-analyses.

CONCLUSIONS

Pooled data suggest that the OSNA assay has a high diagnostic accuracy for the detection of lymph node metastases. For wide spread implementation, additional studies on other different types of tumors are warranted.

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.

Sentinel Lymph Node Mapping with Isosulfan Blue or Indocyanine Green in Colon Cancer Shows Comparable Results and Identifies Patients with Decreased Survival: A Prospective Single-Center Trial

BACKGROUND

Sentinel lymph node (SLN) mapping was reported to improve lymph node staging in colon cancer. This study compares isosulfan blue (IB) with indocyanine green (ICG)-based SLN-mapping and assesses the prognostic value of isolated tumor cells (ITC) and micro-metastases in upstaged patients.

METHODS

A total of 220 stage I-III colon cancer patients were included in this prospective single-center study. In 170 patients, SLN-mapping was performed in vivo with IB and in 50 patients ex vivo with ICG. Three levels of each SLN were stained with H&E. If negative for tumor infiltration, immunostaining for cytokeratin (AE1/3; cytokeratin-19) was performed.

RESULTS

SLN detection rate for IB and ICG was 100 and 98%, respectively. Accuracy and sensitivity was 88 and 75% for IB, 82 and 64% for ICG, respectively (p = 0.244). Overall, 149 (68%) patients were node negative. In these patients, ITC and micro-metastases were detected in 26% (31/129) with IB and 17% (5/29) with ICG (p = 0.469). Patients with ITC and micro-metastases did show decreased overall survival (hazard ratio = 1.96, p = 0.09) compared to node negative disease.

CONCLUSIONS

This study demonstrates a high diagnostic accuracy for both the IB and the ICG SLN-mapping. SLN-mapping upstaged a quarter of patients with node negative colon cancer, and the detected ITC and micro-metastases were an independent negative prognostic marker in multivariate analysis.

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 analysis of sentinel lymph nodes in papillary thyroid cancer patients

INTRODUCTION

It is essential to look for methods to define the need for central lymphadenectomy for papillary thyroid cancer patients. The aim is to determine the efficacy of one-step nucleic acid amplification (OSNA) and sentinel lymph node (SLN) biopsy in the intraoperative detection of nodal involvement.

MATERIAL AND METHODS

This prospective, experimental study enrolled 49 patients with clinically negative lymph nodes. Intraoperatively, 1% Patent Blue dye was injected intratumorally. Lymph nodes that stained blue were defined as SLNs. They were directly cut into blocks at 2-mm intervals. Nonadjacent blocks were subjected to either the OSNA assay or histological examination.

RESULTS

Sixty-five SLNs were found in 43 (87.8%) patients. There were 20 (30.8%) histopathologically positive SLNs. According to the OSNA, 22 (33.8%) SLNs were positive. The OSNA results were different from histopathology in 8 (12.3%) SLNs. The OSNA gave a positive result in 5 (7.7%) SLNs, while they were not involved according to the histopathology. However, OSNA upstaged N status from N0 to N1 only in 2 (3.1%) patients. Inverse results (histopathology +, OSNA-) were obtained in 3 (4.6%) SLNs. Positive and negative predictive values (PPV and NPV) for OSNA were 0.77 and 0.93, respectively. The concordance rate between examinations was 85.5%.

CONCLUSIONS

In some patients with clinically negative lymph nodes, OSNA and SLN biopsy may prevent unnecessary central lymphadenectomy. On the other hand, the sentinel lymph node biopsy may reveal the presence of potentially involved sentinel lymph nodes outside the central compartment. These SLNs can also be assessed by means of OSNA.

Inspection of Perirectal Lymph Nodes by One-Step Nucleic Acid Amplification Predicts Lateral Lymph Node Metastasis in Advanced Rectal Cancer

BACKGROUND

Lateral lymph node dissection (LLND) is performed for advanced rectal cancers in Japan; however, it can cause sexual and urinary dysfunction. The incidence of lateral LN metastasis is estimated at 7-13.9%; therefore, excessive rectal surgery with LLND should be avoided, especially for prophylactic purposes. To identify the patients who require LLND, we examined metastases in perirectal LNs by using a one-step nucleic acid amplification (OSNA) assay to predict lateral LN metastases.

METHODS

Twenty-five patients who underwent surgery with bilateral LN dissection due to T3-T4 rectal cancers were prospectively included in this study. Twenty-two patients (88.0%) received preoperative chemotherapy. Among 1052 LNs from 25 patients (median 40 per case), 135 perirectal LNs (median 6 per patient) were divided into three pieces and analyzed by OSNA, reverse transcriptase-polymerase chain reaction for carcinoembryonic antigen mRNA, and pathological examination after surgery. These results were compared with the pathological diagnosis of lateral LNs.

RESULTS

Lateral LN metastases were present in 4 of 25 patients (16.0%). All of these patients were positive by OSNA for perirectal LN metastases. The OSNA assay had a sensitivity of 100%, specificity of 86%, positive predictive value of 57%, and negative predictive value (NPV) of 100% for predicting lateral LN metastases.

CONCLUSIONS

The findings from this prospective study suggest that the OSNA assay of perirectal LNs may be useful for determining when LLND is necessary because of its high NPV, even in patients treated with preoperative chemotherapy.

Is it time for one-step nucleic acid amplification (OSNA) in colorectal cancer? A systematic review and meta-analysis

BACKGROUND

Lymph node metastasis (LNM) is prognostic in colorectal cancer (CRC). However, evaluation by routine haematoxylin and eosin histology (HE) limits nodal examination and is subjective. Missed LNMs from tissue allocation bias (TAB) might under-stage disease, leading to under-treatment. One-step nucleic acid amplification (OSNA) for CK19 messenger ribonucleic acid (mRNA), a marker of LNM, analyses the whole node. The aim of the present systematic review and meta-analysis was to assess recent studies on OSNA versus HE and its implications for CRC staging and treatment.

METHODS

Databases including OVID, Medline and Google Scholar were searched for OSNA, LNM and CRC. Study results were pooled using a random-effects model. Summary receiver operator curves (SROC) assessed OSNA's performance in detecting LNM when compared to routine HE histology.

RESULTS

Five case-control studies analysing 4080 nodes from 622 patients were included. The summary estimates of pooled results for OSNA were sensitivity 0.90 [95% confidence interval (CI) 0.86-0.93], specificity 0.94 (95% CI 0.93-0.95) and diagnostic odds ratio 179.5 (CI 58.35-552.2, p < 0.0001). The SROC curve indicated a maximum joint sensitivity and specificity of 0.88 and area under the curve of 0.94, p < 0.0001. On average, 5.4% HE-negative nodes were upstaged by OSNA.

CONCLUSIONS

OSNA is as good as routine HE. It may avoid TAB and offer a more objective and standardised assay of LNM. However, for upstaging, its usefulness as an adjunct to HE or superiority to HE requires further assessment of the benefits, if any, of adjuvant therapy in patients upstaged by OSNA.

Molecular analysis of sentinel lymph node in colon carcinomas by one-step nucleic acid amplification (OSNA) reduces time to adjuvant chemotherapy interval

BACKGROUND

The interval between surgery and adjuvant chemotherapy (AC) is a predictive factor of survival in high-risk colon cancer (CC). This study aimed to evaluate the impact of intraoperative sentinel lymph node (SLN) analysis using the one-step nucleic acid amplification (OSNA) technique on the time interval between surgery and AC.

METHODS

We performed a prospective study analyzing 56 consecutive patients who had surgery for CC between July 2012 and October 2014, including 20 patients needing AC. SLN status was determined intraoperatively in 17 patients in the OSNA group; when positive, a portacath (PAC) was placed during the procedure for upcoming AC. In the remaining patients, we proceeded without SLN status determination and the PAC was installed after definitive histopathological analysis of the specimen if needed.

RESULTS

There was no difference between the groups regarding cancer staging, duration of hospitalization (7.5days in the OSNA group and 10days in the control group, p=0.43) and major complications (20% vs 30% respectively, p=0.55). The time interval between surgery and adjuvant chemotherapy was significantly shorter in the OSNA group at 35 (±8) days vs 67 (±36) days (p=0.021).

CONCLUSION

SLN status determination by the OSNA technique is safe, feasible and could significantly reduce time between surgery and adjuvant chemotherapy in a pilot study.

Lymph node pooling: a feasible and efficient method of lymph node molecular staging in colorectal carcinoma

Background

Pathologic lymph node staging is becoming a deficient method in the demanding molecular era. Nevertheless, the use of more sensitive molecular analysis for nodal staging is hampered by its high costs and extensive time requirements. Our aim is to take a step forward in colon cancer (CC) lymph node (LN) pathology diagnosis by proposing a feasible and efficient molecular method in routine practice using reverse transcription loop-mediated isothermal amplification (RT-LAMP).

Results

Molecular detection of tumor cytokeratin 19 (CK19) mRNA with RT-LAMP was performed in 3206 LNs from 188 CC patients using two methods: individual analysis of 1449 LNs from 102 patients (individual cohort), and pooled LN analysis of 1757 LNs from 86 patients (pooling cohort). A median of 13 LNs (IQR 10–18) per patient were harvested in the individual cohort, and 18 LNs (IQR 13–25) per patient in the pooling cohort (p ≤ 0.001). The median of molecular assays performed in the pooling cohort was 2 per patient (IQR 1–3), saving a median of 16 assays/patient. The number of molecular assays performed in the individual cohort was 13 (IQR 10–18), corresponding to the number of LNs to be analyzed. The sensitivity and specificity of the pooling method for LN involvement (assessed by hematoxylin and eosin) were 88.9% (95% CI 56.5–98.0) and 79.2% (95% CI 68.9–86.8), respectively; concordance, 80.2%; PPV, 33.3%; NPV, 98.4%. The individual method had 100% sensitivity (95% CI 72.2–100), 44.6% specificity (95% CI 34.8–54.7), 50% concordance, 16.4% PPV, and 100% NPV. The amount of tumor burden detected in all LNs of a case, or total tumor load (TTL) was similar in both cohorts (p = 0.228).

Conclusions

LN pooling makes it possible to analyze a high number of LNs from surgical colectomies with few molecular tests per patient. This approach enables a feasible means to integrate LN molecular analysis from CC specimens into pathology diagnosis and provides a more accurate LN pathological staging with potential prognostic implications.

Molecularly determined total tumour load in lymph nodes of stage I-II colon cancer patients correlates with high-risk factors. A multicentre prospective study

Stage I–II (pN0) colorectal cancer patients are surgically treated although up to 25 % will eventually die from disease recurrence. Lymph node (LN) status is an independent prognostic factor in colorectal cancer (CRC), and molecular tumour detection in LN of early-stage CRC patients is associated with an increased risk of disease recurrence and poor survival. This prospective multicentre study aimed to determine the relationship between LN molecular tumour burden and conventional high-risk factors in stage I–II colon cancer patients. A total of 1940 LN from 149 pathologically assessed pN0 colon cancer patients were analysed for the amount of tumour cytokeratin 19 (CK19) messenger RNA (mRNA) with the quantitative reverse transcription loop-mediated isothermal amplification molecular assay One-Step Nucleic Acid Amplification. Patient’s total tumour load (TTL) resulted from the sum of all CK19 mRNA tumour copies/μL of each positive LN from the colectomy specimen. A median of 15 LN were procured per case (IQR 12;20). Molecular positivity correlated with high-grade (p < 0.01), mucinous/signet ring type (p = 0.017), male gender (p = 0.02), number of collected LN (p = 0.012) and total LN weight per case (p < 0.01). The TTL was related to pT stage (p = 0.01) and tumour size (p < 0.01) in low-grade tumours. Multivariate logistic regression showed independent correlation of molecular positivity with gender, tumour grade and number of fresh LN [AUC = 0.71 (95 % CI = 0.62–0.79)]. Our results show that lymph node CK19 mRNA detection correlates with classical high-risk factors in stage I–II colon cancer patients. Total tumour load is a quantitative and objective measure that may help to better stage early colon cancer patients.

Comparison of the Diagnostic Value Between Real-Time Reverse Transcription-Polymerase Chain Reaction Assay and Histopathologic Examination in Sentinel Lymph Nodes for Patients With Gastric Carcinoma

OBJECTIVES

Sentinel lymph node (SLN)-based diagnosis in gastric cancers has shown varied sensitivities and false-negative rates in several studies. Application of the reverse transcription-polymerase chain reaction (RT-PCR) in SLN diagnosis has recently been proposed.

METHODS

A total of 155 SLNs from 65 patients with cT1-2, N0 gastric cancer were examined. The histopathologic results were compared with results obtained by real-time RT-PCR for detecting molecular RNA (mRNA) of cytokeratin (CK)19, carcinoembryonic antigen (CEA), and CK20.

RESULTS

The sensitivity and specificity of the multiple marker RT-PCR assay standardized against the results of the postoperative histological examination were 0.778 (95% confidence interval [CI], 0.577-0.914) and 0.781 (95% CI, 0.700-0.850), respectively. In comparison, the sensitivity and specificity of intraoperative diagnosis were 0.819 (95% CI, 0.619-0.937) and 1.000 (95% CI, 0.972-1.000), respectively. The positive predictive value of the multiple-marker RT-PCR assay was 0.355 (95% CI, 0.192-0.546) for predicting non-SLN metastasis, which was lower than that of intraoperative diagnosis (0.813, 95% CI, 0.544-0.960).

CONCLUSIONS

The real-time RT-PCR assay could detect SLN metastasis in gastric cancer. However, the predictive value of the real-time RT-PCR assay was lower than that of precise histopathologic examination and did not outweigh that of our intraoperative SLN diagnosis.

Assessment of lymph node involvement in colorectal cancer

Lymph node metastasis informs prognosis and is a key factor in deciding further management, particularly adjuvant chemotherapy. It is core to all contemporary staging systems, including the widely used tumor node metastasis staging system. Patients with node-negative disease have 5-year survival rates of 70%-80%, implying a significant minority of patients with occult lymph node metastases will succumb to disease recurrence. Enhanced staging techniques may help to identify this subset of patients, who might benefit from further treatment. Obtaining adequate numbers of lymph nodes is essential for accurate staging. Lymph node yields are affected by numerous factors, many inherent to the patient and the tumour, but others related to surgical and histopathological practice. Good lymph node recovery relies on close collaboration between surgeon and pathologist. The optimal extent of surgical resection remains a subject of debate. Extended lymphadenectomy, extra-mesenteric lymph node dissection, high arterial ligation and complete mesocolic excision are amongst the surgical techniques with plausible oncological bases, but which are not supported by the highest levels of evidence. With further development and refinement, intra-operative lymphatic mapping and sentinel lymph node biopsy may provide a guide to the optimum extent of lymphadenectomy, but in its present form, it is beset by false negatives, skip lesions and failures to identify a sentinel node. Once resected, histopathological assessment of the surgical specimen can be improved by thorough dissection techniques, step-sectioning of tissue blocks and immunohistochemistry. More recently, molecular methods have been employed. In this review, we consider the numerous factors that affect lymph node yields, including the impact of the surgical and histopathological techniques. Potential future strategies, including the use of evolving technologies, are also discussed.

Intraoperative fluorescence imaging to localize tumors and sentinel lymph nodes in rectal cancer

Tumor involvement at the resection margin remains the most important predictor for local recurrence in patients with rectal cancer. A careful description of tumor localization is therefore essential. Currently, endoscopic tattooing with ink is customary, but visibility during laparoscopic resections is limited. Near-infrared (NIR) fluorescence imaging using indocyanine green (ICG) could be an improvement. In addition to localize tumors, ICG can also be used to identify sentinel lymph nodes (SLNs). The feasibility of this new technique was explored in five patients undergoing laparoscopic low anterior resection for rectal cancer. Intraoperative tumor visualization was possible in four out of five patients. Fluorescence signal could be detected 32 ± 18 minutes after incision, while ink could be detected 42 ± 21 minutes after incision (p = 0.53). No recurrence was diagnosed within three months after surgery. Ex vivo imaging identified a mean of 4.2 ± 2.7 fluorescent lymph nodes, which were appointed SLNs. One out of a total of 83 resected lymph nodes contained a micrometastasis. This node was not fluorescent. This technical note describes the feasibility of endoscopic tattooing of rectal cancer using ICG:nanocolloid and NIR fluorescence imaging during laparoscopic resection. Simultaneous SLN mapping was also feasible, but may be less reliable due to neoadjuvant therapy.

Management of nodal disease from colon cancer in the laparoscopic era

PURPOSE

In colon cancer (CC), nodal involvement is the main prognostic factor following potentially curative (R0) resection. The purpose of this study was to examine data from the literature to provide an up-to-date analysis of the management of nodal disease with special reference to laparoscopic treatment.

METHODS

MEDLINE and EMBASE databases were searched for potentially eligible studies published in English up to July 15, 2014.

RESULTS

In CC, nodal involvement is a frequent event and represents the main risk of cancer recurrence. Node negative patients recur in 10-30 % of cases most likely due to underdiagnosed or undertreated nodal disease. Extended colonic resections (complete mesocolic excision with central vascular ligation; D3 lymphadenectomy) provides a survival benefit and better local control. Sentinel lymph node mapping in addition to standard surgical resection represents an option for improving staging of clinical node negative patients. Both extended resection and sentinel lymph node mapping are feasible in a laparoscopic setting.

CONCLUSIONS

Both extended colonic resection and sentinel lymph node mapping should play a role in the laparoscopic treatment of CC with the purpose of improving control and staging of nodal disease.