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

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Abstract P3-01-04: Improved sentinel lymph node detection with the use of superparamagnetic iron oxide tracer after neoadjuvant treatment in breast cancer patients

Background. The use of superparamagnetic iron oxide (SPIO) tracer for sentinel node biopsy (SLN) has shown non inferiority compared with the radioisotope technique in early breast cancer. In the neoadjuvant setting (NAC) identification rates with dual technique (blue dye and Tc 99) have been reported to be from 80% to 95%. SLN biopsy false negative (FN) rates after NAC have decreased with the use of dual tracer (radioisotope/ blue dye) and the excision of > 2 SLNs. This study was designed to evaluate the outcome of SLN after NAC using a dual tracer (SPIO and Tc99) versus SLN after NAC with radioisotope (Tc 99) alone.

Material and Methods. After NAC, 188 patients underwent SLN with Tc99 (group Tc99) and 92 patients underwent a SLN with dual technique (group SPIO/Tc99). Inclusion criteria were patients T1-3 N0-1 before NAC and all patients had clinically and /or ultrasound negative axilla before the SLN procedure. Patients were injected subareolar with Tc99 the day before surgery and with the SPIO intraoperatively. SLN was excised if it was radioactive, magnetic or palpable. Patients signed an inform consent. Patients who were N0 pre and postNAC did not undergo an axillary lymph node dissection (ALND) (except for the initial validation patients) , while patients who were N1 pre NAC and N0 post NAC underwent SLN and ALND as part of the protocol.

Results. Mean age of patients between groups were similar, 53.18 (range, 24-90 years old) in the Tc99 group and 52.53 (range, 23-82 years old) in the SPIO/Tc99. Identification rates were 95.72% and 97.8 % in the Tc99 and the SPIO/Tc99 group respectively (p = 0.21). In the Tc99 group, 58 (30.8%) patients were cN1 pre NAC while 13 (14%) in the SPIO/Tc99 (p =0.01). Rates of positive SLN after NAC were 32% in the Tc99 group while 20% in the SPIO/Tc99 group. False negative rates were 4.19% in the Tc99 group (1/50) and 8.3% in the SPIO/Tc99 group (1/13) (p=0.62). There was a statistically significant difference in the median number of SLNs between techniques, being 2.04 in the Tc99 and 2.60 in the SPIO/Tc99 group (p = 0.001). When the mean number of SLNs and the identification rates were differentiated between cN1 and cN0, the statistically significant differences remained unchanged.

Conclusions. The use of dual technique (SPIO and Tc99) for the detection of SLN after NAC increases the identification rates over 97%, better than the reported studies in the NAC setting with Tc99 and blue dye. Although in our study increasing the number of SLNs excised has not decreased the false negative rates, rates of FN are below 10% in both groups. Larger number of cN1 patients is needed in the SPIO/Tc99 technique to validate these initial results. The dual technique with SPIO and Tc99 may optimize the success of SLN after NAC in breast cancer patients.

Citation Format: Rubio IT, Esgueva-Colmenarejo A, Diaz-Botero S, Peg V, Espinosa-Bravo M. Improved sentinel lymph node detection with the use of superparamagnetic iron oxide tracer after neoadjuvant treatment in breast cancer patients. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P3-01-04.

Abstract P2-01-17: Total tumoral load as a prediction tool of non-sentinel node metastases in patients with early breast cancer and positive sentinel lymph node assesed by OSNA

Background: Total tumoral load (TTL) in the sentinel lymph nodes (SLN) assessed by the OSNA assay is a new variable that is able to predict the likelihood of more axillary metastasis. Compared with the number of positive SLNs, the TTL is independent of the number of metastatic SLNs and a better predictor of further nodal metastasis. Although establishing specific cutoff-points of the TTL can be questionable because they may change in the future and increasingly become more patient specific, we have seen that TTL <15.000 could be a good cut off by its high negative predictive value (NPV). Changes in practice have been occurred after the ACOSOG Z0011 trial and nowadays, patients with ≤ 2 positive SLNs may spare an axillary lymph node dissection (ALND) with no impact on the oncological outcome. In the Z0011, 27% of patients had additional non-SLN metastasis in the cALND. The objective of this study was to compare two methods of SLN metastatic burden, the TTL and the number of positive SLNs, for predicting non-SLN metastasis in patients with positive SLNs by OSNA.

Methods: This is a retrospective cohort study of 145 consecutive patients with cT1-T2 invasive breast cancer with ultrasonographically node-negative treated between April 2010 to April 2013, where there is at least one positive SLN assesed by OSNA. We design a prediction tool based on the TTL results determined by OSNA to calculate the likelihood of not finding more positive non-SLN (http://www.vhebron.net/es/calculadora-risc-metastasi-2). Our group have demonstrated that TTL=15.000 could be a good cut off by its high NPV and sensitivity, 85.5% and 76.7%, respectively.

Results: A total 325 SLNs were removed with a mean of 2.24. The type of SLN metastasis were macrometastasis in 85 patients (58.6%) and micrometastasis in 60 patients (41.4%). When considering patients with number of positive SLNs, of 109 patients with ≤2 positives SLNs and an cALND, 17 patients (22%) had non-SLN metastasis; and of 5 patients with ≥3 SLN, four (80%) had non-SLN metastasis. Taking the TTL results, of 51 patients with TTL <15.000 copies/µL with cALND (90.2% with one positive SLN), 7 patients (14%) had non-SLN metastasis, were a media of 2.2 extra non-SLN metastasis.

Of 55 patients with TTL ≥15.000 copies/µL (with 1 or 2 positives SLNs) with cALND, 20 patients (36%) had non-SLN metastasis and there were a media of 2.5 non-SLN metastasis (range 1-8). Of 34 patients (62%) with one positive SLN with TTL ≥15.000 copies/µL, 12 patients (35%) had non-SLN metastasis; and of 21 patients with two positive SLN with TTL ≥15.000 copies/µL, eight patients (38%) had non-SLN metastasis.

Conclusion: The total tumor load obtained by OSNA predicts non-SLN metastasis independent of the number of positive SLNs. The assess of the TTL in our cohort of patients show that patients with one or two positives SLNs with high TTL had high likelihood of non-SLN metastasis greater than 27% of Z0011 criteria. Prospective studies are needed to determine the clinical impact of this variable in patients outcome in the management of patients with SLN assesed by OSNA.

Citation Format: Martin Espinosa-Bravo, Francesc Pérez-Ceresuela, Sebastian Diaz-Botero, Vicente Peg, Isabel T Rubio. Total tumoral load as a prediction tool of non-sentinel node metastases in patients with early breast cancer and positive sentinel lymph node assesed by OSNA [abstract]. In: Proceedings of the Thirty-Seventh Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2014 Dec 9-13; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2015;75(9 Suppl):Abstract nr P2-01-17.

The superparamagnetic iron oxide is equivalent to the Tc99 radiotracer method for identifying the sentinel lymph node in breast cancer

BACKGROUND

Preoperative injection of Tc99 is standardly performed before sentinel lymph node biopsy (SLN) for breast cancer. Multiple questions have arisen concerning appropriate technique for SLNBs including site of injection, timing and injection material. The aim of this study was to assess the concordance between a new method, superparamagnetic iron oxide (SPIO) and the Tc99 radiotracer to identify the SLN in early breast cancer.

MATERIAL AND METHODS

Between July 2013 and March 2014, 120 patients with clinically node negative early breast cancer were included in the study. Patients were injected the day before the radiotracer for lymphoscintigraphy and injected the SPIO subareolar intraoperatively. SLN was excised if it was radioactive, magnetic or palpable. Patients signed an inform consent.

RESULTS

There was no drainage by either technique in 2 patients, so this leaves 118 patients for further analysis. Detection rate by Tc 99 was successful in 113 (95.7%%) patients and by SPIO in 116 (98.3%). Concordance rates per patient between techniques was 98.2%. The SLN was positive in 36 (30%) patients. Of this, SLN positivity was detected by both techniques in 32 patients. Mean number of SLNs by 99Tc and SPIO were 1.9 and 2.21 respectively (p = 0.001).

DISCUSSION

Detection of SLNs with SPIO allows for easy identification of axillary nodes, at a frequency not inferior to the radiotracer. It is an oncologically safe procedure, facilitates patients and operative room management and can be used to reliably identify SLNs in breast cancer.

Increased detection of sentinel nodes in breast cancer patients with the use of superparamagnetic iron oxide tracer

100

Background: The use of superparamagnetic iron oxide (SPIO) tracer for sentinel node biopsy (SLN) has shown non inferiority compared with the radioisotope technique in early breast cancer. False negative rates of SLN biopsy after neoadjuvant treatment (NAC) have decreased with dual tracer (radioisotope/dye) and with the excision of > 2 SLNs. This study was designed to evaluate the outcome of SLN after NAC using a dual tracer (SPIO-Tc99) and to compare it with the SLN by same dual tracer in the adjuvant setting. Methods: Between July 2013 and March 2014, 30 patients with invasive breast cancer (IBC) and SLN biopsy after NAC (NAC- SLN), and 118 patients with IBC not treated with NAC (adjuvant SLN), whose SLN was traced by Tc99 and SPIO were included in the study. Patients were injected subareolar with Tc99 the day before surgery and with the SPIO intraoperatively. SLN was excised if it was radioactive, magnetic or palpable. Patients signed an inform consent. Results: Detection rate by Tc 99 was successful in 113 (95.7%) patients and by SPIO in 116 (98.3%) in the adjuvant SLN (P= 0.0833) while in the NAC-SLN group detection rate by Tc-99 was successful in 28 patients (93.3%) and by SPIO in 30 patients (100%) (P =0.1573). Concordance rates per patient in the adjuvant SLN between techniques was 98.2%, while in the NAC-SLN was 100%. (p = 0.4762) Mean number of SLNs excised by 99Tc and SPIO were 1.9 and 2.21 respectively in the adjuvant SLN, (p=0.001) while 1.533 and 2.60 respectively in the NAC-SLN group. (p=0.0016) In the adjuvant SLN, the SLN was positive in 36 patients (30%), and in the NAC-SLN in 9 patients (30%). In the adjuvant SLN, both techniques detected same number of positive nodes but in the NAC-SLN, 9 patients had a positive SLN by SPIO (> 2 SLNs by SPIO and 1 SLN by Tc99) and 7 patients had a positive SLN by Tc99. Conclusions: Detection of SLNs with SPIO allows for easy identification of axillary nodes and can be used to reliably identify SLNs in breast cancer. Even though the small sample size in the NAC-SLN, the higher number of SLNs excised by the SPIO may optimize the success of SLN after NAC.

Positive sentinel lymph node: the evolution of axillary surgery and intraoperative assessment of sentinel lymph nodes

SUMMARY 

Axillary lymph node dissection (ALND) has been the treatment for breast cancer in patients with sentinel lymph node (SLN) biopsy metastasis for prognostic information, local control and maybe for a small survival benefit. In recent years, clinicians have been questioning the need for axillary dissection in patients with positive SLN as the rate of axillary recurrences remains low when no ALND is performed in this group. Several variables incorporated in nomograms have been examined to predict axillary metastasis in patients with SLN metastasis and these nomograms have helped to determine which patients can spare the morbidity of the ALND. The combined multimodality in breast cancer treatments and the improvement in targeted therapies based in tumor biology have contributed to the low recurrence rates in early-stage breast cancer. As the multimodal treatment and the screening programs will improve, more patients with SLN metastasis will spare an ALND without compromising their oncologic outcome.