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

Evaluation of RASSF1A methylation in the lysate of sentinel lymph nodes for detecting breast cancer metastasis: A diagnostic accuracy study

The restriction enzyme-based digital methylation-specific polymerase chain reaction (RE-dMSP) assay is useful for diagnosing sentinel lymph node (SN) metastasis in patients with breast cancer, by detecting tumor-derived methylated Ras association domain-containing protein 1 (RASSF1A). In addition, this assay has high concordance (95.0%) with one-step nucleic acid amplification (OSNA). The present study aimed to perform RE-dMSP using OSNA lysate from more patients and to re-evaluate its clinical usage. Overall, 418 SNs from 347 patients were evaluated using both OSNA and RE-dMSP. The concordance rate was 83.3% (348/418). RASSF1A methylation of the primary tumors was negative in 36 patients. When these patients were excluded, the concordance rate improved to 88.2% (330/374). Of the 79 OSNA-negative cases, 19 were RE-dMSP-positive, although all were positive for cytokeratin 19 expression in the primary tumor, suggesting that RE-dMSP can detect tumor-derived DNA with a higher sensitivity. The percent of methylated reference of the breast tumors showed a wide variety in the 16 OSNA-positive/RE-dMSP-negative cases, and such variability of methylation could have affected the results in these patients. In conclusion, although RE-dMSP can diagnose SN metastasis with high sensitivity and accuracy, and can be a supplementary tool to OSNA in breast cancer, RE-dMSP showed certain discordance with OSNA and critically depended on the absence or heterogeneity of DNA methylation in breast tumors. Further research is expected to develop an assay targeting other DNA alterations, such as mutations.

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

PURPOSE

This 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.

METHODS

This 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).

RESULTS

A 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).

CONCLUSION

No 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.

Axillary Treatment Management in Breast Cancer during COVID-19 Pandemic (Association between ACOSOG Z0011 Criteria and OSNA Test)

The outbreak of the SARS-COVID-2 pandemic (COVID-19) had a significant effect on the organisation of healthcare systems. Surgical units saw a significant reduction in the volume of surgical procedures performed, with lengthening waiting lists as a consequence. We assessed the surgical activity in relation to breast cancer that took place at the University Hospital of Cagliari, Italy, from February 2018 to March 2022. Two phases were identified based on the epidemiological circumstances: Phase 1-February 2018 to February 2020; Phase 2-March 2020 to March 2022. The surgery performed in the two phases was then compared. All the patients in our sample underwent a breast surgical procedure involving a lymph node biopsy using OSNA associated with the ACOSOG Z0011 criteria. In the study period overall at our facility, there were 4214 procedures, 417 of which involved breast surgery. In Phase 2, 91 procedures were performed using the OSNA method and ACOSOG Z0011 criteria, enabling the intraoperative staging of axillary nodes. Axillary treatment in breast cancer using this approach resulted in a significant reduction in the number of reoperations for the radicalisation of metastatic sentinel lymph nodes.

A Nomogram Based on Molecular Biomarkers and Radiomics to Predict Lymph Node Metastasis in Breast Cancer

Background

The aim of this study was to explore the feasibility and efficacy of a non-invasive quantitative imaging evaluation model to assess the lymphatic metastasis of breast cancer based on a radiomics signature constructed using conventional T1-weighted image (T1WI) enhanced MRI and molecular biomarkers.

Methods

Patients with breast cancer diagnosed via lymph biopsies between June 2015 and June 2019 were selected for the study. All patients underwent T1WI contrast-enhancement before treatment; lymph biopsy after surgery; and simultaneous Ki-67, COX-2, PR, Her2 and proliferating cell nuclear antigen detection. All images were imported into ITK-SNAP for whole tumor delineation, and AK software was used for radiomics feature extraction. Next, the radiomics signature Rad-score was constructed after reduction of specific radiomic features. A multiple regression logistic model was built by combining the Rad-score and molecular biomarkers based on the minimum AIC.

Results

In all, 100 patients were enrolled in this study, including 45 with non-lymph node (LN) metastasis and 55 with LN metastasis. A total of 1,051 texture feature parameters were extracted, and LASSO was used to reduce the dimensionality of the radiomics features. The log(λ) was set to 0.002786, and 19 parameters were retained for the construction of the radiomics tag Rad-score. ROC was used to evaluate the diagnostic efficiency of Rad-score: the area under the ROC curve (AUC) of the Rad-score for identifying non-lymphatic and lymphatic metastases was 0.891 in the training cohort and 0.744 in the validation cohort. With the incorporation of tumor molecular markers, the AUCs of the training cohort and validation cohort of the nomogram were 0.936 and 0.793, respectively, which were notably higher than the AUCs of the clinical parameters in the training and validation cohorts (0.719 and 0.588, respectively).

Conclusion

The combined model constructed using the Rad-score and molecular biomarkers can be used as an effective non-invasive method to assess LN metastasis of breast cancer. Furthermore, it can be used to quantitatively evaluate the risk of breast cancer LN metastasis before surgery.

Axillary staging based on molecular analysis: Results of the B-CLOSER-II study

INTRODUCTION

Axillary staging (pN) is a strong predictor of outcome in early stage breast cancer yet following the publication of the Z0011 trial there has been an increasing tendency to spare lymph node dissection. Automated molecular detection of cytokeratin 19mRNA by one-step nucleic acid amplification (OSNA) has been demonstrated to be an accurate method to assess sentinel lymph node (SLN) metastasis. In this study we compare histological and molecular methods following complete axillary lymph node dissection (cALND), determine whether molecular axillary staging affects survival, and evaluate the predictive and prognostic value of total tumor load in ALND (AD-TTL) and in all positive nodes (G-TTL).

MATERIAL AND METHODS

Axillary lymph nodes were collected from 102 patients with primary breast cancer with histological confirmation of axillary involvement (cN+) or positive SLN. The central 1-mm portion of each non-SLN was processed for hematoxylin-eosin staining and the remaining tissue was analyzed by OSNA.

RESULTS

Non-SLNs were diagnosed as positive in 72 out of 102 patients (70.6 %) on OSNA compared with only 53 (52 %) on histology (p < 0.01). Thirteen patients would have changed staging if the diagnoses provided had been by molecular methods (p < 0.01), but without a change in prognosis. AD-TTL and G-TTL were predictive of recurrence and mortality.

CONCLUSIONS

Compared to molecular detection, histological examination significantly underestimates the frequency of axillary node metastases. However, the increase in pN did not show a clinical effect on survival in those patients.

Highly sensitive detection of sentinel lymph node metastasis of breast cancer by digital PCR for RASSF1A methylation

One-step nucleic acid amplification (OSNA) targeting cytokeratin 19 (CK19) mRNA expression and pathological examination are widely used for the intraoperative diagnosis of sentinel node (SN) metastasis. The aim of the present study was to develop a novel assay for detecting SN metastasis by targeting Ras association domain-containing protein 1 (RASSF1A) methylation in tumor cells, and to compare its performance with OSNA. Using digital PCR with methylation-specific restriction enzymes (RE-dMSP), our assay was able to detect ≥3 copies of methylated DNA per well, and was ≥10 times more sensitive than real-time PCR with bisulfite modification. OSNA lysates were examined using RE-dMSP and digital PCR for PIK3CA mutation, in the event that primary tumors were PIK3CA mutation-positive. RE-dMSP revealed a high concordance of 95.0% (153/161) with OSNA, and 100% (59/59) with PIK3CA mutation for detecting SN metastasis. In 11 breast cancer cell lines, the variation in methylated RASSF1A copy number was significantly lower than that of CK19 mRNA (2.8 vs. 10.5-fold; P<0.01). RE-dMSP has the potential to more accurately detect SN metastasis, and to more precisely estimate total tumor loads in SN, compared with OSNA.

Drainage of Tumor-Derived DNA into Sentinel Lymph Nodes in Breast Cancer Patients

Circulating tumor DNA (ctDNA) is released from cancer cells by apoptosis or other mechanisms, and as tumor tissue contains both blood and lymphatic vessels, ctDNA can spread to local lymph nodes (LNs). We aimed to detect the tumor-derived free DNA in metastasis-free LNs in patients with breast cancers harboring the PIK3CA-H1047R mutation. One hundred twenty-three patients were evaluated and the PIK3CA-H1047R mutation was assayed in sentinel LNs (SLNs), non-SLNs without metastasis, and serum by digital PCR. The mutant DNA was more frequent in metastasis-free SLNs (21.6%) than in metastasis-free non-SLNs (8.6%; P = 0.038), and patients with mutation-positive SLNs were more likely to be positive for serum mutant DNA. Apoptosis in primary breast tumors was determined by TUNEL assay. The apoptotic index was significantly higher (P = 0.003) in patients with mutation-positive SLNs without metastasis (mean, 1.17%) than those with mutation-negative SLNs without metastasis (mean, 0.79%). It was also significantly higher (P = 0.006) in those with mutation-positive serum (mean, 1.41%) than in those with mutation-negative serum (mean, 0.86%). Furthermore, fragment size of PIK3CA-H1047R mutant DNA in metastatic-free SLN lysate used for the one-step nucleic acid amplification (OSNA) assay was short (<500 bp). These results support the theory that DNA is released from the primary tumor via apoptotic fragmentation. In conclusion, ctDNA is detectable in metastasis-free LNs and significantly more frequent in SLNs from patients with breast tumors harboring a high apoptotic index, consistent with drainage of ctDNA from apoptotic primary tumor cells into SLNs.

Maspin mRNA expression in sentinel lymph nodes predicts non-SLN metastasis in breast cancer patients with SLN metastasis

AIMS

Maspin is known to be a tumour suppressor protein, but its prognostic significance in breast cancer patients is controversial. There is no report focusing on maspin expression in metastatic carcinoma of sentinel lymph nodes (SLNs); we thus investigated maspin mRNA expression in SLNs using the remaining specimens after the one-step nucleic acid amplification (OSNA) assay.

METHODS AND RESULTS

Ninety-three breast cancer patients with SLNs metastasis detected by the OSNA assay were enrolled. All patients experienced additional axillary lymph nodes (LNs) dissection and all dissected LNs were examined histopathologically. Maspin mRNA expression in SLNs was detected in 49.5% (46 of 93) and was correlated significantly with the presence of non-SLN metastasis (P < 0.0001) and ≥4 LN metastases (P = 0.029). In a multivariate logistic analysis, maspin mRNA expression in SLNs (P = 0.0015) had the most significant effect on predicting non-SLN metastasis, followed by pathological tumour size (P = 0.0039) and lymphovascular invasion (P = 0.009). The status of maspin mRNA expression in SLNs was correlated significantly with that of maspin protein expression in the primary carcinoma (P < 0.0001).

CONCLUSIONS

This is the first study, to our knowledge, demonstrating that maspin mRNA expression in SLNs is an independent predictor of non-SLN metastasis and the presence of ≥4 LN metastases in breast cancer patients with SLN metastasis. The investigation of maspin mRNA expression in SLNs using the remaining specimens after the OSNA assay may be useful for predicting the further progression of metastatic carcinoma in breast cancer patients with SLNs metastasis.

Intraoperative Nomograms, Based on One-Step Nucleic Acid Amplification, for Prediction of Non-sentinel Node Metastasis and Four or More Axillary Node Metastases in Breast Cancer Patients with Sentinel Node Metastasis

Background

One-step nucleic acid amplification (OSNA) for cytokeratin 19 messenger RNA is an intraoperative diagnostic procedure for the detection of lymph node metastasis.

Objective

This study aimed to construct intraoperative nomograms using OSNA for the prediction of non-sentinel lymph node (NSLN) metastasis and four or more axillary lymph node (ALN) metastases.

Methods

Of the 4736 breast cancer patients (T1-3, N0) who underwent sentinel lymph node (SLN) biopsy and had SLNs examined intraoperatively with OSNA, 623 with SLN metastasis treated with completion ALN dissection (cALND) were retrospectively analyzed, and were randomly divided into training (n = 312) and validation (n = 311) sets.

Results

Of the clinicopathological parameters available preoperatively and intraoperatively, the multivariate analysis of the training set revealed that clinical tumor size and total tumor load (TTL) determined by OSNA were significantly associated with NSLN metastasis, and that clinical tumor size, number of macrometastatic SLNs, and TTL were significantly associated with four or more ALN metastases. Nomograms for NSLN metastasis and four or more ALN metastases were constructed using these parameters, and their area under the receiver operating characteristic curve (AUC) of the validation set were both 0.70, with a diagnostic accuracy similar to that of previously reported postoperative nomograms.

Conclusions

We constructed intraoperative nomograms using OSNA for the prediction of NSLN metastasis and four or more ALN metastases. These nomograms are as accurate as the conventional postoperative nomograms and might be helpful for decision making regarding the indication for cALND or the choice of adjuvant chemotherapeutic regimens and radiation field.

Electronic supplementary material

The online version of this article (10.1245/s10434-018-6633-0) contains supplementary material, which is available to authorized users.

One-Step Nucleic Acid Amplification in Breast Cancer Sentinel Lymph Node: A Single Institutional Experience and a Short Review

Sentinel lymph node (SLN) examination is a standard in breast cancer patients, with several methods employed along its 20 years history, the last one represented by one-step nucleic acid amplification (OSNA). The latter is a intra-operative molecular assay searching for CK19 mRNA as a surrogate of metastatic cells. Our 3 years experience with OSNA (1122 patients) showed results overlapping those recorded in the same institution with a morphological evaluation (930 patients) of SLN. In detail, the data of OSNA were almost identical to those observed with standard post-operative procedure in terms of patients with positive SLN (30%) and micrometastatic/macrometastatic involvement of SLN (respectively, 38–45 and 62–55%). By contrast, when OSNA was compared to the standard intraoperatory procedure, it was superior in terms of accuracy, prompting the use of this molecular assay as a very valid, and reproducible for intra-operative evaluation of SLN. Further possibilities prompting the use of OSNA range from adhesion to quality control programs, saving of medical time, ability to predict, during surgery, additional nodal metastasis, and molecular bio-banking.

Clinical significance of breast cancer micrometastasis in the sentinel lymph node

The advantages of sentinel lymph node biopsy (SLNB) in breast cancer patients include an enhanced pathological examination of a small number of sentinel lymph nodes (SLNs), which permits more frequent detection of micrometastasis and isolated tumor cells (ITCs). At the same time, however, SLNB raises two new concerns: whether minimal SLN involvement has a significant impact on survival and whether patients with such minimal involvement should undergo further axillary dissections. Two large randomized studies, ACOSOG Z0011 and IBCSG 23-01, have demonstrated that axillary lymph node dissection (ALND) can be avoided for select SLN-positive patients. However, for patients with macrometastasis in SLN or who do not meet the inclusion criteria of the two studies, ALND is still the standard management. On the other hand, previous studies appear to disagree on the prognostic significance of minimal SLN involvement. One of the reasons for this discrepancy is the great variability among pathological examinations for SLN. The OSNA method, which is a fast molecular detection procedure targeting cytokeratin 19 (CK19) mRNA, has the advantage of reproducibility among institutions and the capability to examine a whole lymph node within 30-40 min. This novel method may thus be able to overcome the issue of variability among conventional pathological examinations.

Clinical usefulness of one-step nucleic acid amplification assay in the new era of sentinel lymph node biopsy for breast cancer

SUMMARY 

According to the results of the ACOSOG Z0011 trial and IBCSG trial 23-01, rapid intraoperative examinations of the sentinel lymph nodes (SLN) are needed in only a limited number of breast cancer patients, including those with more than three sentinel nodes or who undergo mastectomy. In this new era of SLN biopsies, one-step nucleic acid amplification assay is a promising method for accurately assessing metastasis in the whole SLN, and which help to accurately select patients requiring axillary dissection and reliably evaluate the risk of recurrence. One-step nucleic acid amplification assay may therefore be an alternative to conventional pathology in detecting metastasis in the SLNs, when used for both intraoperative and postoperative examinations.

OSNA (one-step nucleic acid amplification) sentinel lymph node intraoperative molecular analysis in breast cancer: a cost-benefit analysis

The aim of the study was to analyze the medical and economic interest of OSNA molecular technique, compared to conventional postoperative histopathologic evaluation for sentinel lymph node exploration in breast cancer patients. This retrospective cost-benefit study was conducted in the French Universitary Hospital of Saint Etienne on patients who received sentinel lymph node exploration between July 1, 2007 and December 31, 2009. Lymph nodes were analyzed by conventional postoperative histological evaluation in group 1 (82 patients) and OSNA in group 2 (86 patients). Costs were analyzed in three different ways: surgery cost, hospitalization cost and histopathologic cost. Average operating time was slightly shorter for group 1 (histology) [71.9 vs. 76.8 min for group 2 (OSNA)]. Time and operating costs were not significantly different (p = 0.293). The average cost of pathological examination was significantly higher in group 2 (35.04 euros per node in group 1 vs. 291.84 euros per node in group 2 p < 10(-3)). The average length of hospital stay was significantly longer in group 1 (5.4 days in group 1 vs. 4.2 days in group 2, p = 0.0065). The total costs were not significantly different between both groups (3,774.6 euros in group 1 vs. 3,393.9 euros in group 2 p = 0.055). The sentinel lymph node analysis with OSNA technique does not lead to higher expenses. It also avoids another surgery for 20% of patients. A prospective multicentric medico-economic study made with a larger effective would probably confirm these results.