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

Outcomes in patients with non‐invasive breast carcinoma

BACKGROUND AND AIM

Non-invasive breast carcinoma is considered to be localized disease and is distinguished from invasive ductal and lobular carcinomas. The local recurrence of non-invasive carcinoma after surgery may lead to development of invasive carcinoma and promote distant metastasis, which worsens the prognosis for breast cancer mortality. The distant metastasis of non-invasive carcinoma may involve the ductal microvasculature without invasion. The outcomes of non-invasive breast carcinoma were examined in this retrospective cohort study.

METHODS AND RESULTS

Of 872 primary breast cancers diagnosed at a single center between May 2008 and March 2022, 93 (10.6%) were found to be non-invasive carcinomas and were examined in this study. The breast cancer recurrence and survival rates of patients with non-invasive carcinoma were analyzed retrospectively. The median follow-up period was 1891 (range, 5-4804) days. All patients underwent surgical treatment [mastectomy with sentinel lymph node biopsy (SLNB) and partial mastectomy with or without SLNB, tumorectomy, and microdochectomy]. Postoperatively, radiation therapy was administered to 73 (78.4%) of the patients and endocrine therapy was administered to 64 (81.0%) of 79 patients with hormone-receptor positivity. Of 26 patients who underwent partial mastectomy with SLNB, 24 (92.3%) showed isolated tumor cells in the SLNs on one-step nucleic acid amplification. Local recurrence was observed in three (0.3%) patients; no distant metastasis was observed. One patient died of a noncancerous disease. The overall survival rate was 98.0% and the breast cancer-specific survival rate was 100.0%.

CONCLUSIONS

Non-invasive breast carcinoma, like invasive breast carcinoma, causes local recurrence, but has a good prognosis without distant metastasis. The clinical significance of isolated tumor cells in the SLNs as a systemic component of non-invasive breast carcinoma remains to be elucidated.

Trends in Axillary Surgery for Treating Ductal Carcinoma In Situ: A Korean Population-based Study

Purpose

Ductal carcinoma in situ (DCIS) is common in South Korea. We evaluated the patterns of axillary surgery among patients with DCIS to highlight the need for compliance with the updated national guidelines. We also evaluated whether sentinel lymph node biopsy (SLNB) was performed in accordance with the national guidelines.

Methods

The Korean Health Insurance Review and Assessment Service-National Inpatient Sample database was searched for patients with DCIS (2009–2015) to identify axillary surgery patterns by breast surgery type, year of diagnosis, age at diagnosis, and the location and volume of surgeries for DCIS at the hospital. The rates of SLNB and axillary dissection were compared using descriptive statistics and univariate analyses. Analyses were also conducted using the chi-squared test and multiple logistic regression analysis.

Results

We identified 16,315 Korean women who underwent surgery for DCIS, including 11,292 cases of SLNB (69.2%) and 131 cases of axillary lymph node dissection (0.8%). Breast-conserving surgery (BCS) was performed in 10,323 patients (63.3%) with an SLNB rate of 56.0%, while total mastectomy (TM) was performed in 5,992 patients (36.7%), with an SLNB rate of 92.0%. During 2009–2015, the SLNB rate during TM increased from 88.23% to 92.80%. SLNB was influenced by hospital region and surgical volume, and hospitals performing low volumes of surgeries were significantly more likely to perform SLNB regardless of the surgery type (odds ratio, 1.372; 95% confidence interval, 1.265–1.488).

Conclusion

Although the Korean guidelines recommend SLNB for all TM procedures and select BCS procedures for DCIS, relatively high rates of SLNB were performed for BCS, and there was inter-hospital variability in performing SLNB. Improved compliance with the guidelines by the surgeons is critical for Korean patients with DCIS.

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.

Effect of preoperative injection of superparamagnetic iron oxide particles on rates of sentinel lymph node dissection in women undergoing surgery for ductal carcinoma in situ (SentiNot study)

Background

One-fifth of patients with a preoperative diagnosis of ductal carcinoma in situ (DCIS) have invasive breast cancer (IBC) on definitive histology. Sentinel lymph node dissection (SLND) is performed in almost half of women having surgery for DCIS in Sweden. The aim of the present study was to try to minimize unnecessary SLND by injecting superparamagnetic iron oxide (SPIO) nanoparticles at the time of primary breast surgery, enabling SLND to be performed later, if IBC is found in the primary specimen.

Methods

Women with DCIS at high risk for the presence of invasion undergoing breast conservation, and patients with DCIS undergoing mastectomy were included. The primary outcome was whether this technique could reduce SLND. Secondary outcomes were number of SLNDs avoided, detection rate and procedure-related costs.

Results

This was a preplanned interim analysis of 189 procedures. IBC was found in 47 and a secondary SLND was performed in 41 women. Thus, 78·3 per cent of patients avoided SLND (P < 0·001). At reoperation, SPIO plus blue dye outperformed isotope and blue dye in detection of the sentinel node (40 of 40 versus 26 of 40 women; P < 0·001). Costs were reduced by a mean of 24·5 per cent in women without IBC (€3990 versus 5286; P < 0·001).

Conclusion

Marking the sentinel node with SPIO in women having surgery for DCIS was effective at avoiding unnecessary SLND in this study. Registration number: ISRCTN18430240 (http://www.isrctn.com).

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

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

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.

Current approach and future perspective for ductal carcinoma in situ of the breast

Ductal carcinoma in situ (DCIS) has a good prognosis with the current treatment approach, with a 10-year breast cancer-specific survival rate of 97-98%. In ductal carcinoma in situ without micrometastasis, surgery and postoperative adjuvant therapy significantly improve local control, however it has been reported that the selection of the surgical procedure and adjuvant therapy does not influence breast cancer death. On the other hand, owing to widespread mammography screening, the frequency of early breast cancer detection has increased. In early breast cancer, increased incidence of DCIS is remarkable. However, there is not enough reduction of advanced cancer to match it. Problems with overdiagnosis are now being discussed all over the world. It has been reported that surgery for low-grade ductal carcinoma in situ does not contribute to breast cancer-specific survival. However, it is currently impossible to reliably identify a population that does not progress to invasive cancer even without treatment. Recently, a non-surgery clinical trial for low-risk ductal carcinoma in situ was started. There is a possibility of achieving individualized treatment for ductal carcinoma in situ with less treatment intervention, without compromising the good prognosis obtained with the current treatment approach. This review presents an overview of the current treatment approaches, problems with overdiagnosis and potential future management strategies for ductal carcinoma in situ of the breast.

Simplifying Logistics and Avoiding the Unnecessary in Patients With Breast Cancer Undergoing Sentinel Node Biopsy. A Prospective Feasibility Trial of the Preoperative Injection of Super Paramagnetic Iron Oxide Nanoparticles

PURPOSE

Sentinel node is routinely localized with the intraoperative use of a radioactive tracer, involving challenging logistics. Super paramagnetic iron oxide nanoparticle is a non-radioactive tracer with comparable performance that could allow for preoperative localization, would simplify the procedure, and possibly be of value in axillary mapping before neoadjuvant treatment. The current trial aimed to determine the a priori hypothesis that the injection of super paramagnetic iron oxide nanoparticles in the preoperative period for the localization of the sentinel node is feasible.

METHODS

This is a prospective feasibility trial, conducted from 9 September 2014 to 22 October 2014 at Uppsala University Hospital. In all, 12 consecutive patients with primary breast cancer planned for resection of the primary and sentinel node biopsy were recruited. Super paramagnetic iron oxide nanoparticles were injected in the preoperative visit in the outpatient clinic. The radioactive tracer (⁹⁹mTc) and the blue dye were injected perioperatively in standard fashion. A volunteer was injected with super paramagnetic iron oxide nanoparticles to follow the decline in the magnetic signal in the sentinel node over time. The primary outcome was successful sentinel node detection.

RESULTS

Super paramagnetic iron oxide nanoparticles' detection after preoperative injection (3-15 days) was successful in all cases (100%). In the volunteer, axillary signal was presented for 4 weeks. No adverse effects were noted. Conclusion and relevance: Preoperative super paramagnetic iron oxide nanoparticles' injection is feasible and leads to successful detection of the sentinel node. That may lead to simplified logistics as well as the identification, sampling, and marking of the sentinel node in patients planned for neoadjuvant treatment.

Minimal Clinical Impact of Intraoperative Examination of Sentinel Lymph Nodes in Patients With Ductal Carcinoma In Situ: An Opportunity for Improved Resource Utilization

OBJECTIVES

There is little information regarding sentinel lymph node (SLN) frozen-section examination in patients with a history of ductal carcinoma in situ (DCIS). We evaluated the usage, clinical impact, and pathology resources used for SLN cryosectioning in mastectomy cases with a DCIS history.

METHODS

Mastectomies with SLNs submitted from 2012 to 2013 at a tertiary care center were analyzed. Medicare reimbursement was used to estimate pathology health care expenditures of intraoperative frozen sections.

RESULTS

There was no difference in the rate of SLN frozen-section examination or parts submitted, total blocks frozen, total blocks submitted, or total SLNs identified per case between the DCIS (n = 139) and invasive (n = 369) groups. Nine patients with DCIS had SLN metastases (three macrometastases, two micrometastases, and four isolated tumor cells), all of which were examined by frozen section. Only the macrometastases were identified by cryosectioning, which led to two synchronous axillary lymph node dissections that did not yield any additional positive nodes. A total of $19,313 was spent for pathology per DCIS patient with surgical management affected, whereas only $1,019 was spent per invasive carcinoma patient affected.

CONCLUSIONS

Decreasing SLN frozen-section use in patients with a history of DCIS represents an opportunity for pathology cost containment.

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

Background:

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

Methods:

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

Results:

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

Conclusions:

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

Is sentinel lymph node biopsy indicated in patients with a diagnosis of ductal carcinoma in situ? A systematic literature review and meta-analysis

BACKGROUND

Recent discussion has suggested that some cases of ductal carcinoma in situ (DCIS) with high risk of invasive disease may require sentinel lymph node biopsy (SLNB).

METHODS

Systematic literature review identified 48 studies (9,803 DCIS patients who underwent SLNB). Separate analyses for patients diagnosed preoperatively by core sampling and patients diagnosed postoperatively by specimen pathology were conducted to determine the percentage of patients with axillary nodal involvement. Patient factors were analyzed for associations with risk of nodal involvement.

RESULTS

The mean percentage of positive SLNBs was higher in the preoperative group (5.95% vs 3.02%; P = .0201). Meta-regression analysis showed a direct association with tumor size (P = .0333) and grade (P = .00839) but not median age nor tumor upstage rate.

CONCLUSIONS

The SLNB should be routinely considered in patients with large (>2 cm) high-grade DCIS after a careful multidisciplinary discussion. In the context of breast conserving surgery, the SLNB is not routinely indicated for low- and intermediate-grade DCIS, high-grade DCIS smaller than 2 cm, or pure DCIS diagnosed by definitive surgical excision.

One Step Nucleic Acid Amplification (OSNA) positive micrometastases and additional histopathological NSLN metastases: Results from a single institution over 53 months

INTRODUCTION

The role of sentinel lymph node micrometastases on histopathological analysis is controversial in axillary staging and management in clinically node negative breast cancer. Long-term studies addressing the clinical relevance of occult breast cancer in sentinel lymph nodes based on molecular analysis are lacking. One Step Nucleic Acid Amplification (OSNA), a highly sensitive assay of cytokeratin 19 mRNA, is used intra-operatively for the detection of lymph node macro- and micrometastases in breast cancer.

AIM

The aim of this study is to review the rate of micrometastases and further histopathological NSLN metastases, in our unit following the introduction of OSNA in Guildford.

METHODS

Data was collected prospectively from the period of introduction 01/12/2008 to 31/05/2013. All patients eligible for sentinel lymph node biopsy were offered OSNA and operations were performed by the consultant breast surgeons. Presence or absence of micro-metastases depends on the agreed cut-off point on the amplification curve. On detection of micrometastases (+) and positive but inhibited (i+) metastases, a level 1 axillary clearance (ANC) was performed and for a macrometastasis (++), a level 3 ANC was carried out.

RESULTS

66% of the patients had negative SLN (n = 672) and 34% (n = 336) had positive sentinel lymph nodes who had further axillary surgery. Of these, 45% (n = 152/336) had macrometastases, 40% (n = 136/336) had micrometastases and 15% (48/336) had positive but inhibited results. There was no difference in the patient demographics and tumour characteristics in the various positive SLN groups. In patients with micrometastases, 15% (20/136) had further positive NLSNs and a further 6% (8/136) had >4 overall positive nodes (SLN + NSLN) thus requiring adjuvant supraclavicular/chest wall radiotherapy (p < 0.05). 25% of node positive patients had further NLSN metastases (85/336) and in these patients, the ratio of positive SLN/harvested SLN (+SLN/SLN) is constant at 1:1. This shows the likelihood of further positive NSLNs if all the harvested lymph nodes are positive. This linear trend is present in both micro-and macrometastases, thus correlating with the size and number of NSLN metastases.

CONCLUSION

Our study reflects the tumour burden of NSLNs based on the molecular analysis of the SLN. OSNA has the potential to accurately identify axillary micrometastases. Micro-metastases are important as some of the patients with micrometastases had overall four positive nodes [SLN + NSLN] (criteria for radiotherapy in the absence of other adverse clinicopathological features). Also, our study highlights certain factors that predict the NSLN metastases, pending validation by further prospective long-term data. This will allow accurate calculation of the axillary tumour burden, particularly in patients with micro-metastases.

Assessment of suitability of the one step nucleic acid amplification (OSNA) assay as an intraoperative procedure for detection of metastasis in sentinel lymph nodes of breast cancer

AIM

We aimed to assess the one step nucleic acid amplification (OSNA) assay as an intraoperative method in comparison with frozen sections (FS) for detection of metastasis in sentinel lymph nodes (SLNs) of breast cancer.

METHOD

100 SLNs from patients with breast carcinoma were enrolled within a 3-month period. Alternate 2 mm node slices were subjected to routine FS, and later to permanent histology, and the rest for automated molecular detection of CK19 mRNA using OSNA. FS and OSNA findings were compared with permanent histology results. Difference in turnaround time was also noted.

RESULTS

With permanent histology as gold standard, OSNA was discrepant in 8 of 98 (3 false negative, 5 false positive) included SLNs whereas FS had 2 false negative cases. FS had higher sensitivity (89%, p=<0.001), specificity (100%, p=0.001) and concordance rate (98%) than OSNA (83%, 94% and 92%, respectively). FS showed almost perfect agreement (κ=0.929) whereas OSNA showed substantial agreement (κ=0.740) when compared with permanent histology. OSNA turnaround time was twice longer (mean of 47.7 min) than FS.

CONCLUSIONS

Automation of SLN assessment using OSNA is a potentially useful intraoperative diagnostic tool with acceptable accuracy. Discordant findings in this study may be due to sampling allocation. Since OSNA is more time-consuming, its practical advantage over routine FS requires further study in view of current technical workflow considerations.

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

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

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

Using one-step nucleic acid amplification (OSNA) for intraoperative detection of lymph node metastasis in breast cancer patients avoids second surgery and accelerates initiation of adjuvant therapy

BACKGROUND

Sentinel lymph node (SLN) analysis is conventionally analyzed using immunohistochemistry and in the case of SLN involvement, justifies a second surgery for axillary lymph node (ALN) resection, thus delaying the initiation of adjuvant therapies.

PATIENTS AND METHODS

Three hundred and eighty-one patients with early stage breast cancer (BC) were considered in this retrospective study. SLNs were detected using combined radioisotope and dye detection. SLN involvement was analyzed using routine intraoperative One-Step Nucleic Acid Amplification (OSNA) assay, in 100 patients and compared with the conventional histopathology carried out previously in 281 patients.

RESULTS

Considering positive SLNs as '++' (CK19 mRNA copy number>5000), '+' (250 < CK19 mRNA copy number <5000) and positive by inhibition in the OSNA group and macro-, micrometastases and isolated tumor cells in the histopathology group, no difference in SLN involvement rate was found between the two groups with 29.0% and 29.9% of positive SLNs, respectively. Using OSNA intraoperatively, the mean time to process the SLN was 42 min allowing immediate ALN resection, reduced significantly (P < 0.01) the re-intervention rate (9% versus 39%) and significantly (P < 0.01) accelerated the initiation of adjuvant therapy (6.2 versus 8.4 weeks).

CONCLUSIONS

Using OSNA for intraoperative SLN analysis avoids second surgery for ALN resection in most patients and accelerates initiation of adjuvant therapy.

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

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