Step Nucleic Acid Amplification Research Articles

Value of total tumor load as a clinical and pathological factor in the prognosis of breast cancer patients receiving neoadjuvant treatment. Comparison of three populations with three different surgical approaches: NEOVATTL Pro 3 Study

PurposeThis study aimed to compare the prognosis in terms of disease-free survival (DFS) in three populations of women with breast cancer (BC) treated with neoadjuvant systemic treatment (NAST) in which axillary lymph node dissection (ALND) was performed based on different total tumor load (TTL) thresholds in the sentinel nodes.MethodsThis was an observational, retrospective study carried out in three Spanish centers. Data from patients with infiltrating BC who underwent BC surgery after NAST and intraoperative sentinel lymph node biopsy (SLNB) performed by One Step Nucleic acid Amplification (OSNA) technique during 2017 and 2018 were analyzed. ALND was performed according to the protocol of each center, based on three different TTL cut-offs (TTL > 250, TTL > 5000, and TTL > 15,000 CK19-mRNA copies/μL for centers 1, 2, and 3, respectively).ResultsA total of 157 BC patients were included in the study. No significant differences in DFS were observed between centers (Hazard ratio [HR] center 2 vs 1: 0.77; p = 0.707; HR center 3 vs 1: 0.83; p = 0.799). Patients with ALND had a shorter DFS (HR 2.43; p = 0.136), albeit not statistically significant. Patients with a triple negative subtype had a worse prognosis than those with other molecular subtypes (HR 2.82; p = 0.056).ConclusionNo significant differences in DFS were observed between three centers with different surgical approaches to ALND based on different TTL cut-offs in patients with BC after NAST. These results suggest that restricting ALND to those patients with TTL ≥ 15,000 copies/μL is a reliable approximation, avoiding unnecessary morbidities caused by ALND.

Tumour Cell Seeding to Lymph Nodes from In Situ Colorectal Cancer.

Lymph node (LN) metastasis is an important prognostic factor in colorectal cancer (CRC). We aimed to demonstrate the presence of lymphatic vessels (LV) in the mucosa of in-situ (pTis) CRC, and of detectable tumour burden in regional LNs. This is an observational retrospective study of 39 surgically resected in situ CRCs. The number of LVs was evaluated in both pTis and normal mucosa using D2-40 immunostains. All LNs were assessed with both H&E and the One Step Nucleic Acid Amplification (OSNA) assay, and the results were correlated with clinicopathological features. D2-40 immunohistochemisty revealed LVs in the lamina propria of all pTis CRC (100%), being absent in normal mucosa. A median of 16 LNs were freshly dissected per patient, and all cases were pN0 with H&E. Molecular LN analysis with OSNA revealed the presence of low amounts of tumour burden in 11/39 (28%) cases (range 400 to 4270 CK19 mRNA copies/µL), which had no clinical consequences. This study demonstrates the presence of LVs in the lamina propria in 100% of pTis CRC, as well as the presence of low amounts of tumour burden in regional LNs, only detected by molecular methods. Given the prognostic value of LN tumour burden, its molecular quantification may help a patient's clinical management.

One Step Nucleic Acid Amplification (OSNA) Lysate Samples Are Suitable to Establish a Transcriptional Metastatic Signature in Patients with Early Stage Hormone Receptors-Positive Breast Cancer.

The One Step Nucleic Acid Amplification (OSNA) is being adopted worldwide for sentinel lymph nodes (SLNs) staging in breast cancer (BC). As major disadvantage, OSNA precludes prognostic information based on structural evaluation of SLNs. Our aim is to identify biomarkers related to tumor-microenvironment interplay exploring gene expression data from the OSNA remaining lysate. This study included 32 patients with early stage hormone receptors-positive BC. Remaining OSNA lysates were prepared for targeted RNA-sequencing analysis. Identification of differentially expressed genes (DEGs) was performed by DESeq2 in R and data analysis in STATA. The results show that, in metastatic SLNs, several genes were upregulated: KRT7, VTCN1, CD44, GATA3, ALOX15B, RORC, NECTIN2, LRG1, CD276, FOXM1 and IGF1R. Hierarchical clustering analysis revealed three different clusters. The identified DEGs codify proteins mainly involved in cancer aggressiveness and with impact in immune response. The overexpression of the immune suppressive genes VTCN1 and CD276 may explain that no direct evidence of activation of immune response in metastatic SLNs was found. We show that OSNA results may be improved incorporating microenvironment-related biomarkers that may be useful in the future for prognosis stratification and immunotherapy selection. As OSNA assay is being implemented for SLNs staging in other cancers, this approach could also have a wider utility.

245 (PB-069) Poster - Exploring the lymph node’s microenvironment for personalized management of luminal A breast cancer

Background: Lymph nodes (LNs) are the main doorway for tumor cell metastasis from the primary site and its evaluation is a major prognostic factor. The One Step Nucleic Acid Amplification (OSNA) is being adopted worldwide for sentinel-LNs (SLNs) staging in breast cancer (BC). SLNs’ OSNA lysate may be used for gene expression studies, being the potentially ideal samples to search for new markers related to immune response. Using a targeted gene expression approach, we aim to identify transcriptomic patterns of SLNs immune response and biomarkers that may improve risk stratification and personalized therapy for patients with Luminal A early stage BC.

One step nucleic acid amplification (OSNA) for detection of lymph node metastasis during robotic radical prostatectomy for prostate cancer: A pilot study

The OSNA technique is based on reverse transcription loop-mediated DNA amplification for the detection of cytokeratin 19 (CK19) messen-ger RNA (mRNA). The purpose of our paper, which represents the first study in the literature, is to test the accuracy of this method in the detection of lymph node metastases in patients undergoing robotic radical prostatectomy with lymph node dis-section. Our cohort consisted of patients that have undergone robotic radical prostatectomy with extended lymph node dissec-tion. Lymph nodes were evaluated with imprint technique and then with frozen section examination. The remaining tissue was evaluated by OSNA method. Lymph nodes were defined as 'neg-ative' or 'positive' according to mRNA copy number. 7 patients and 25 lymph nodes were included in our cohort. Two patients were found negative with all pathology methods. In one patient the standard stains revealed a suspi-cious outcome but it was positive for micrometastasis with OSNA. In another patient the outcome was positive for standard stains and negative for OSNA. Finally, 2 patients were found positive for OSNA and negative for imprint methods. One Step Nucleic Acid Amplification (OSNA) method using CK19 seems to fail in detection of lymph node metastases in prostate cancer patients undergoing radical prostatectomy and lymph node dissection.

Intraoperative predictive model for the detection of metastasis in non-sentinel axillary lymph nodes

Background: To design a software-applied predictive model relating patients clinical and pathological traits associated with sentinel lymph-node total tumor load to individually establish the need to perform an axillary lymph-node dissection. Methods: Retrospective observational study including 127 patients with breast cancer in which a sentinel lymph-node biopsy was performed with the one step nucleic acid amplification method and a subsequent axillary lymph-node dissection. We created various binary multivariate logistic regression models using non-automated methods to predict the presence of metastasis in non-sentinel lymph-nodes, including Log total tumor load, immunohistochemistry, multicentricity and progesterone receptors. These parameters were progressively added according to the simplicity of their evaluation and their predictive value to detect metastasis in non-sentinel lymph-nodes. Results: The final model was selected for having maximum discriminatory capability, good calibration, along with parsimony and interpretability. The binary logistic regression model chosen was the one which identified the variables Log total tumor load, immunohistochemistry, multicentricity and progesterone receptors as predictors of metastasis in non-sentinel lymph-nodes. Harrell’s C-index obtained from the area under the curve of the predicted probabilities by Model 4 was 0.77 (95% CI, 0.689–0.85; p < 0.0005). Conclusions: the combination of total tumor load, immunohistochemistry, multicentricity and progesterone receptors can predict 77% of patients with metastasis in non-sentinel lymph-nodes and said prediction may be made intraoperatively in a feasible manner.

Sentinel Nodal Micrometastases Detected by the One- Step Nucleic Acid Amplification Whole Node Assay and the Impact on Adjuvant Treatment and Outcomes in Early Breast Cancers: The First Report from Thailand

Background: The advent of sentinel lymph node biopsy (SLNB) and improvements in histopathological and molecular analysis have increased the detection rate of nodal micrometastases. As compare with conventional method, the one-step nucleic acid amplification (OSNA) assay might detect higher cases of SLN micrometastases. Objective: The present study aimed to assess the impact of OSNA assay on micrometastases detection rate and potential benefit in terms of adjuvant treatment and survival outcome in early breast cancer. Materials and Methods: A retrospective review of patients with sentinel node (SLN) micrometastasis detected by the OSNA assay between 2015 and 2019 was carried out. Clinicopathological, adjuvant treatment, and follow-up data were collected. Ten-year survival benefit with adjuvant chemotherapy was calculated using PREDICT online, version 1.2 (https://breast.predict.nhs.uk/). Results: Between November 2015 and December 2019, 78 out of 721 patients (10.8%) were positive for micrometastasis based on OSNA detection. Three-fourth of cases received adjuvant systemic chemotherapy and 57% were given taxane-based regimen. Using the PREDICT online tool, an estimated 10-year survival in patients who received adjuvant systemic chemotherapy and who did not, were 75% and 66%, respectively (p=0.018). A 10-year survival benefit from chemotherapy among patients who received systemic chemotherapy was 8% compared with 4% with no-adjuvant-therapy cohort. Conclusion: The OSNA assay allows for a more precise detection of SLN micrometastasis compared to conventional pathology and could guide therapeutic decision making. In patients with micrometastasis who received adjuvant systemic chemotherapy, the estimated overall 10-year survival was improved. Keywords: Axillary staging, Breast cancer, Micrometastases, OSNA, Sentinel lymph node biopsy

P017. The impact of one step nucleic-acid amplification (OSNA) availability on management of the axilla in early breast cancer

P017. The impact of one step nucleic-acid amplification (OSNA) availability on management of the axilla in early breast cancer

Usefulness of histological superstudy of sentinel lymph nodes detected with radioisotopes in colon cancer

IntroductionAdjuvant chemotherapy (CT) significally reduces the rate of relapse in +pN (stage III) colon cancer (CC) and in some pN0 (stage II) with risk factors such as pT4, vascular invasion V1, perineural invasion Pn1, and complicated tumors. However, unexpectedly, 20%–30% of pN0 present a relapse in the follow-up, which may suggest that the lymph node involvement was not discovered in the conventional histological study (CS), and its finding with a superstudy (SS) could increase the number of patients who would benefit from neoadjuvant CT. It is not possible to perform this SS in every lymph node (LN) from the specimen, but it is possible in a small group of LN which are representative of the N status (definition of sentinel node SN). The aim of our work is to state the representativeness of the SN and to analyze de number of patients who are suprastaged after the SS of the SN. Material and MethodsProspective study of a series of patients who have undergone curative surgery for CC, to whom we perform selective biopsy of sentinel node (SBDN). Identification of SN was carried out with in vivo injection of the radiotracer, with ex vivo isolation of SN. Once the specimen is out, we take pictures of the surgical bed to rule out the presence of aberrant drainage routes, out of the routine oncological resection area. We performed the histological CS (Hematoxilin-Eosin stain (H-E) in conventional sections) in the rest of the LN from the mesocolon. In the SN we performed the CS and a SS with H-E in serial sections, immunohistochemistry (IHC) and molecular study with OSNA® (One Step Nucleic Acid Amplification). Diagnostic validity study od SBSN was carried out, defining the false negative (FN) as the negativity of the SN while other LN are positive (N+), as well as a valuation of the suprastaging due to the SS of the SN. ResultsWe performed lymphatic map in 72 patients, finding the SN in 62 of them (87.3%). The 9 identification failures happened in the first 17 cases. We have not found aberrant drainage routes. A total of 1.164 LN were studied in the 62 patients (18.8 LN/patient), from which 145 are SN (2,34 SN/patient), having found 103 positive LN with the CS and 112 positive with the SS of SN (9+ LN more in 8 patients than detected with the CS). Positivity after CS in the SN group is 17.24% (25/145), while it is 8.53% in the rest (87/1.019) (P < .001). With the CS, 50% of the patients (31/62) were pN+ (4 are N+ exclusively in the SN), and after the SS of the SN, only 1 of the 31 pN0 patients (3.2%) becomes pN1a, with a definitive 51.6% of N+ in the whole series (32 N+ in the 62 patients) (5 are N+ exclusively in the SN).Exclusively with the SS of the SN, FN rate (“-SN, +others”, meaning patients who are N+ having -SN) is 54.8% (17/31). With the SS of the SN, 8 of the 62 patients (12.9%) increase their total number of +LN: apart from the patient who turns from pN0 to pN1a, suprastaging from IIA to IIIB (and therefore increasing the total number of pN+ to 32), 5 of the 17 FN in the CS turns into positive (2 change the pN subindex and one is suprastaged from IIIB to IIIC), decreasing FN to 37.5% (12/32 cases). Besides, 2 patients whose SN is already positive in the CS increase the number of +SN after the SS of the SN, therefore both changing their pN subindex and one of them suprastaging from IIIB to IIIC. In summary, 8 patients increase the total number of positive SN after the SS (8/62, 12.9%), 5 of them changing the pN subindex (5/62, 12.9%), even if only 3 of them get suprastaged (3/62, 4.8%), among them the one who turns from pN0 to pN1a. ConclusionTechnique is valid and reproducible, with a high detection rate even with a high learning curve. It globally increases the number of affected LN in 12.9% of patients, having prognostic implications in 4.8% (suprastaging rate). Only 3.2% of pN0 patients in the CS turn to be +pN after the SS of the SN, with its therapeutic implications (prescription of adjuvant CT), which could be relevant when extrapolated to a big number of patients. The high FN rate (37.5%) prevents us from accepting the representativeness of SN as the global N status, but it is not clinically relevant in CC, as its aim is not to avoid lymphadenectomy, which remains mandatory (opposite to breast cancer or melanoma in which SN detection decides upon whether to perform or not the lymphadenectomy), but to decide which patients would benefit from adjuvant CT.

Utilidad del superestudio anatomopatológico de ganglio centinela detectado con radioisótopos en el cáncer de colon

IntroductionAdjuvant chemotherapy (CT) significally reduces the rate of relapse in +pN (stage III) colon cancer and in some pN0 (stage II) with risk factors such as pT4, vascular invasion V1, perineural invasion Pn1, and complicated tumors. However, unexpectedly, 20-30% of pN0 present a relapse in the follow-up, which may suggest that the lymph node involvement was not discovered in the conventional histological study (CS), and its finding with a superstudy (SS) could increase the number of patients who would benefit from neoadjuvant CT. It is not possible to perform this SS in every lymph node (LN) from the specimen, but it is possible in a small group of LN which are representative of the N status (definition of sentinel node SN). The aim of our work is to state the representativeness of the SN and to analyze de number of patients who are suprastaged after the SS of the SN. Material and methodsProspective study of a series of patients who have undergone curative surgery for colon cancer, to whom we perform selective biopsy of sentinel node. Identification of SN was carried out with in vivo injection of the radiotracer, with ex vivo isolation of SN. Once the specimen is out, we take pictures of the surgical bed to rule out the presence of aberrant drainage routes, out of the routine oncological resection area. We performed the histological CS (hematoxilin-eosin stain in conventional sections) in the rest of the LN from the mesocolon. In the SN we performed the CS and a SS with hematoxilin-eosin in serial sections, immunohistochemistry (IHC) and molecular study with One Step Nucleic Acid Amplification (OSNA®). Diagnostic validity study od selective biopsy of sentinel node was carried out, defining the false negative (FN) as the negativity of the SN while other LN are positive (N+), as well as a valuation of the suprastaging due to the SS of the SN. ResultsWe performed lymphatic map in 72 patients, finding the SN in 62 of them (87.3%). The 9 identification failures happened in the first 17 cases. We have not found aberrant drainage routes. A total of 1.164 LN were studied in the 62 patients (18.8 LN/ patient), from which 145 are SN (2,34 SN/ patient), having found 103 positive LN with the CS and 112 positive with the SS of SN (9 +LN more in 8 patients than detected with the CS). Positivity after CS in the SN group is 17.24% (25/145), while it is 8.53% in the rest (87/1.019) (p<.001). With the CS, 50% of the patients (31/62) were pN+ (4 are N+ exclusively in the SN), and after the SS of the SN, only 1 of the 31 pN0 patients (3.2%) becomes pN1a, with a definitive 51.6% of N+ in the whole series (32 N+ in the 62 patients) (5 are N+ exclusively in the SN).Exclusively with the SS of the SN, FN rate (“-SN, +others”, meaning patients who are N+ having -SN) is 54.8% (17/31). With the SS of the SN, 8 of the 62 patients (12.9%) increase their total number of +LN: apart from the patient who turns from pN0 to pN1a, suprastaging from IIA to IIIB (and therefore increasing the total number of pN+ to 32), 5 of the 17 FN in the CS turns into positive (2 change the pN subindex and one is suprastaged from IIIB to IIIC), decreasing FN to 37.5% (12/32 cases). Besides, 2 patients whose SN is already positive in the CS increase the number of +SN after the SS of the SN, therefore both changing their pN subindex and one of them suprastaging from IIIB to IIIC. In summary, 8 patients increase the total number of positive SN after the SS (8/62, 12.9%), 5 of them changing the pN subindex (5/62, 12.9%), even if only 3 of them get suprastaged (3/62, 4.8%), among them the one who turns from pN0 to pN1a. ConclusionTechnique is valid and reproducible, with a high detection rate even with a high learning curve. It globally increases the number of affected LN in 12.9% of patients, having prognostic implications in 4.8% (suprastaging rate). Only 3.2% of pN0 patients in the CS turn to be +pN after the SS of the SN, with its therapeutic implications (prescription of adjuvant CT), which could be relevant when extrapolated to a big number of patients. The high FN rate (37.5%) prevents us from accepting the representativeness of SN as the global N status, but it is not clinically relevant in colon cancer, as its aim is not to avoid lymphadenectomy, which remains mandatory (opposite to breast cancer or melanoma in which SN detection decides upon whether to perform or not the lymphadenectomy), but to decide which patients would benefit from adjuvant CT.

Is it Possible to Predict Non Sentinel Node Positivity on the Basis of mRNA Copy Numbers of CK19 Receptor in Breast Cancer?

AimsTo determine if there is any correlation between the number of positive non-sentinel lymph nodes (NSLN) and the mRNA copy numbers of cytokeratin 19 receptor on one step nucleic acid amplification (OSNA) in the sentinel lymph node (SLN). MethodsAn 8-year retrospective study of consecutive patients who had primary surgery and sentinel node biopsy for breast cancer from January 2011 to December 2018 was carried out. All these patients had intra-operative analysis of sentinel lymph nodes by OSNA. Patients who had neoadjuvant chemotherapy or neoadjuvant endocrine therapy were excluded. ResultsThere were 1159 patients with an age range of 24 to 90 years and a mean age of 63 years in this study. A total of 1324 SLNs were analyzed by OSNA. Macrometastasis was found in 120 patients and they underwent axillary lymph node dissection (ALND). A total of 2405 NSLNs were analyzed. Of the patients who had ALND, 51 (43%) patients had negative NSLNs and 69 (57%) had positive NSLNs. The mean mRNA copy numbers respectively for the 2 groups were 853,665 and 609,855. The difference between the means is not statistically significant (P = 0.82). Also the Receiver Operating Characteristic (ROC) Curve of the total CK-19 mRNA copy number for both groups-negative and positive NSLN were almost identical (Figure 3) indicating mRNA copy numbers cannot be used to discriminate between positive and negative non-sentinel lymph nodes. ConclusionIt is clear from our study that in patients who have ALND due to macromets on OSNA, there is no correlation between the total tumor load as represented by mRNA copy numbers and the likelihood of positive non-sentinel lymph nodes. We therefore cannot rely solely on the mRNA copy numbers to decide on ALND.

Is it possible to predict non sentinel node positivity on the basis of mRNA copy numbers of CK19 receptor in breast cancer?

Background: One step nucleic acid amplification (OSNA) has found wide acceptance as a tool for intraoperative assessment of the sentinel lymph node (SLN). This is a semiquantitative assay based on quantification of mRNA copy numbers of cytokeratin 19 (CK19) receptor. The study aimed to determine if there is any correlation between the number of positive non sentinel lymph nodes (NSLN) and the mRNA copy numbers of CK19 receptor on OSNA in the SLN.

Evaluation of accuracy of One Step Nucleic acid Amplification (OSNA) in diagnosis of lymph node metastases of papillary thyroid carcinoma: a comparison between real-time PCR and histopatology

Papillary thyroid carcinoma (PTC) is the most common malignant thyroid neoplasia, representing 80% of thyroid tumors, progressively increased in the last decades by the diffusion of screening ultrasound. The incidence of node metastases is high, ranging from 20% to 90%.

External validation of a prognostic model based on total tumor load of sentinel lymph node for early breast cancer patients

BackgroundA prognostic model based on the results of molecular analysis of sentinel lymph nodes (SLN) is needed to replace the information that staging the entire axilla provided. The aim of the study is to conduct an external validation of a previously developed model for the prediction of 5-year DFS in a group of breast cancer patients that had undergone SLN biopsy assessed by the One Step Nucleic Acid Amplification (OSNA) method.MethodsWe collected retrospective data of 889 patients with breast cancer, who had not received systemic treatment before surgery, and who underwent SLN biopsy and evaluation of all SLN by OSNA. The discrimination ability of the model was assessed by the area under the ROC curve (AUC ROC), and its calibration by comparing 5-years DFS Kaplan–Meier estimates in quartile groups of model predicted probabilities (MPP).ResultsThe AUC ROC ranged from 0.78 (at 2 years) to 0.73 (at 5 years) in the training set, and from 0.78 to 0.71, respectively, in the validation set. The MPP allowed to distinguish four groups of patients with heterogeneous DFS (log-rank test p < 0.0001). In the highest risk group, the HR were 6.04 [95% CI 2.70, 13.48] in the training set and 4.79 [2.310, 9.93] in the validation set.ConclusionsThe model for the prediction of 5-year DFS was successfully validated using the most stringent form of validation, in centers different from those involved in the development of the model. The external validation of the model confirms its utility for the prediction of 5-year DFS and the usefulness of the TTL value as a prognostic variable.

Intraoperative imprint cytology of sentinel lymph nodes in breast cancer patients: Comparation with frozen section

Background/Aim. Sentinel lymph node (SLN) biopsy has been established as the standard of care for axillary staging in patients with invasive breast carcinoma and clinically negative lymph nodes. Intraoperative assessment of sentinel lymph nodes might be done by frozen section (FS), touch imprint cytology (TIC) and one step nucleic acid amplification. The aim of this study was to review our institution's results with SLN biopsy using TIC and FS technique as intraoperative diagnostic tool for breast cancer patients. Methods. SLNs from 101 patients were examined intraoperatively by frozen hematoxylin-eosin (H&amp;E) stain and by touch imprint cytology. Results of TIC were compared with FS and permanent histology sections. Results. The total number of dissected SLNs was 163 with a mean of 1.6 (1?4) per patient. The permanent H&amp;E identified 19 (19%) patients with a sentinel lymph node metastasis and 82 (81%) patients with tumor-free sentinel nodes. The sensitivity/ specificity rates were 73.7%/99.3%, respectively for TIC and 84.2%/100%, respectively for FS. Relevant positive/ negative predictive values were 93.3%/96.6%, respectively for TIC and 100%/97.9%, respectively for FS. Conclusion. Our experience with TIC and FS for the intraoperative evaluation of SLNs is similar to the findings from previously reported studies. We detected the high specificity for both methods, but TIC technique appeared to be less sensitive than FS in detecting SLN metastases in breast cancer patients. TIC could be recommended as reasonable alternative to frozen section due to its simplicity and low cost.

Evaluation of accuracy of one-step nucleic acid amplification (OSNA) in diagnosis of lymph node metastases of papillary thyroid carcinoma. Diagnostic study.

BackgroundThe incidence of node metastases in papillary thyroid carcinoma (PTC) is high, ranging from 20% to 90%. Prophylactic central lymph node compartment dissection (CLND), suggested from the latest guidelines for high-risk tumors, meets resistance due to the high incidence of postoperative complications. Recently, new molecular biologic techniques, such as One Step Nucleic Acid Amplification (OSNA), have spread widely, allowing to quickly isolate, amplify and quantify mRNA encoding for proteins selectively present in neoplastic cells, as Cytokeratine-19. The aim of this study is to evaluate the application of OSNA to intraoperative diagnosis of node metastases of PTC.MethodsWe included in the study patients with preoperative diagnosis of PTC; from each patient one or more lymph nodes were collected. To assess OSNA accuracy, each lymph node was divided into two halves: the first one was analysed with histopathological and immunohistochemical examination, whereas the second was studied with OSNA.ResultsTwenty-six lymph nodes from 13 patients were included in the study. Overall, OSNA sensitivity was 87.5%, specificity 94.4%, positive predictive value 87.5%, negative predictive value 94.4% and accuracy 92.8%.Discussion and conclusionOSNA is effective in detecting lymph node metastases of PTC. Considering the high risk of complications in CLND, and the uncertain prognostic value of lymph node metastases of PTC, OSNA seems to be a promising tool to identify intraoperatively patients who may benefit from CLND.

One step nucleic acid amplification (OSNA): one step ahead in gynecological surgical oncology

One step nucleic acid amplification (OSNA): one step ahead in gynecological surgical oncology

No relationship of axillary total tumor load (TTL) by PCR (OSNA) in early breast cancer and local and distant clinical outcomes.

564 Background: The study of sentinel lymph nodes (SLN) assessed by One Step Nucleic Acid Amplification (OSNA, Sysmex, Kobe, Japan) creates a new variable, Total Tumor Load (TTL). This variable is defined as the total number of CK19 mRNA copies in all positive SLN (copies/microL). The latest edition of the Spanish Oncological Gynecology Society (SEGO) Guideline (2017) proposes a complete axillary lymph node dissection (ALND) when TTL is 15,000 copies or more in early breast cancer. In our center we are using OSNA to ascertain if there is axillary node involvement but the decision to proceed to ALND is based on Z0011 criteria. We want to determine if there is a correlation between clinical outcomes and TTL values, between TTL and pathological variables and if TTL is a useful tool to decide when to complete an ALND. Methods: Clinicopathological and follow up data were obtained from all patients with invasive breast cancer and SLN assessed by OSNA between 2011 and 2017 at our center. Results: A total of 321 patients underwent SNB assessed by OSNA with an average follow-up of 56 months. 320 were female and 1 male. Age range 27-89 years (mean 58.9). 85 % were ductal, 10 % lobular and 5 % other. 53.5% were luminal A, 28.66% luminal B, 7.78%, triple negative, 4.3%, Her2 positive and 4.3%. luminal B-Her2 positive.TTL was equal to 0 in 183 cases and greater than zero in 138 cases.71 cases showed a TTL higher than 15,000 copies. Only 21 cases met Z0011 criteria and had ALND. As of now, 3 patients have had locoregional relapse and 8 metastatic disease. 12 have died, only two from metastatic breast cancer. Conclusions: Using Z0011 criteria, we have adequate clinical outcomes with a low rate of ALND; If we had based the axillary management on TTL values we would have multiplied the number of ALND by a factor of 3.3 (from 21 to 71); We have observed a tendency to higher TTL in luminal phenotypes and to lower TTL in HER2 positive and triple negative subtypes; Work is in progress to increase our sample size.

P006. Does the Total Tumour Load (TTL) as detected by One Step Nucleic Acid Amplification (OSNA) predict Non Sentinel Node Positivity?

Introduction: It has been suggested that TTL can be used to predict non-sentinel node positivity in breast cancer by dividing patients into low (TTL<2.5x104) and high risk categories (TTL>2.5x104). This is of increasing relevance as there is a move to more conservative axillary treatment in the post ACOSOG Z0011 era. Our objective was to test this theory for validity.

P016. Can we use OSNA (One Step Nucleic acid Amplification) routinely in DCIS? – A single centre study

P016. Can we use OSNA (One Step Nucleic acid Amplification) routinely in DCIS? – A single centre study