Results of preoperative lymphoscintigraphy for breast cancer are predictive of identification of axillary sentinel lymph nodes

Is preoperative imaging of sentinel lymph node in breast cancer necessary? A retrospective case control study

OBJECTIVE

The necessity of preoperative lymphoscintigraphy before intraoperative sentinel lymph node (SLN) identification is still unclear. The aim of the present study was to evaluate the impact of SLN imaging on intraoperative SLN detection in breast cancer patients.

METHODS

Retrospective, comparative, single center study of patients with breast cancer stage pT1 and pT2 who underwent axillary staging. Group 1 included patients who underwent SLN extirpation without preoperative SLN imaging, and Group 2 included patients who underwent SLN imaging prior to surgery. Differences between groups were analyzed using T-test and chi-square test.

RESULTS

926 (mean age: 61.45 years) patients received subdermal injection of radiolabeled nanocolloids between tumor and axilla. SLN was identified intraoperatively in 473 of 498 patients (94.98 %) in group 1, and in 415 of 428 patients (96.96 %) in group 2 (p = 0.129). Lymphoscintigraphy detected SLN in 407 of 428 (95.09 %) patients in group 2. Due to the additional SLN imaging in group 2, the time between radiotracer injection and start of surgery was significantly prolonged (p < 0.001). A reduction of applied activity from a median of 18 MBq in group 1 to a median of 12 MBq in group 2 had no negative effect on the SLN identification.

CONCLUSION

Subdermal injection of radiolabeled nanocolloids between tumor and axilla allowed high intraoperative detection of SLN. Preoperative SLN imaging had no significant impact on the intraoperative detection but is a time-consuming and resource-intensive procedure. Prospective studies might provide further evidence to omit preoperative SLN imaging in patients with T1-2 invasive breast cancer and clinically negative axilla.

Biological Subtypes of Breast Cancer and Sentinel Lymph Node Biopsy

Objective

Breast cancer subtypes are used as prognostic and predictive factors considering the genomic profile of the disease. This study is designed to investigate the Sentinel Lymph Node (SLN) detection rate in breast cancer for different biological characteristics.

Material and Methods

Patients on whom we performed the methylene blue method alone were named as Group I, radiocolloid substance method alone as Group II and both methylene blue and radiocolloid method as Group III. The results of biological tumor characteristics and characteristics of the patients on different SLN biopsy techniques were investigated.

Results

The overall SLN detecting success rate was 83.3%. When considered for each group, success rate was 80% for group I, 84.9% for group II and 90.6% for group III. While a success rate of 94.6% was achieved with radiocolloid only in the patients in Luminal A and B subgroup, 90% success rate was achieved in Her2 (+) and triple negative (TN) patients with combined method.

Conclusion

While successful results could be achieved by using radiocolloid substances alone in patients with Luminal A and B subtypes, combined methods should be used in HER2 (+) and TN patients.

λ-Eye: a high-sensitivity γ imaging probe for axillary sentinel lymph node mapping

OBJECTIVE

The aim of this study is the construction and performance evaluation of 'λ-eye', a γ imaging probe, optimized in terms of sensitivity for sentinel lymph node mapping. The optimization of the probe is based on theoretical models and simulation results that were presented in a previous study of our group. In this work, the construction of the probe, the experimental confirmation of the simulation results, and the evaluation of its performance with phantoms and lymph node imaging in small animals are presented.

METHODS

The system's spatial and energy resolution, sensitivity, and count rate performance were measured using phantoms. The values of the integral and differential uniformity in the useful field-of-view and in the central field-of-view were also calculated. Finally, a proof-of-concept animal experiment was conducted for the imaging of the lymph nodes of normal mice.

RESULTS

The system's energy resolution was measured as 36±2% and the spatial resolution was 2.2 mm at 2 mm source-collimator distance. The values of the integral uniformity and differential uniformity in the useful field-of-view and in the central field-of-view were found to be 5.2, 2.1, 1.7, and 0.75%, respectively. Finally, the lymph nodes of normal mice were clearly imaged with a 10 s acquisition time.

CONCLUSION

The 'λ-eye', used for sentinel lymph node mapping, provides a combination of high sensitivity (∼1.5 counts/s/kBq) and good spatial resolution (∼6 mm full-width of the half-maximum at 20 mm and ∼10 mm full-width of the half-maximum at 50 mm distance). Its compact size (40 mm×40 mm×70 mm) allows its use during surgery and/or for the detailed scan of a suspicious region.

Discordance between number of scintigraphic and perioperatively identified sentinel lymph nodes and axillary tumour recurrence

BACKGROUND

In breast cancer, sentinel node biopsy is considered the standard method to assess the lymph node status of the axilla. Preoperative identification of sentinel lymph nodes (SLN) is performed by injecting a radioactive tracer, followed by lymphoscintigraphy. In some patients there is a discrepancy between the number of lymphoscintigraphically identified sentinel nodes and the number of nodes found during surgery. We hypothesized that the inability to find peroperatively all the lymphoscintigraphically identified sentinel nodes, might lead to an increase in axillary recurrence because of positive SLNs not being removed.

METHODS

Patients who underwent sentinel node biopsy between January 2000 and July 2010 were identified from a prospectively collected database. The number of lymphoscintigraphically and peroperatively identified sentinel nodes were reviewed and compared. Axillary recurrences were scored.

RESULTS

1368 patients underwent a SLN biopsy. Median follow up was 58.5 months (range 12-157). Patient and tumour characteristics showed no significant differences. In 139 patients (10.2%) the number of radioactive nodes found during surgery was less than preoperative scanning (group 1) and in 89.8% (N = 1229) there were equal or more peroperative nodes identified than seen lymphoscintigraphically (group 2). In group 1, 0/139 patients (0%) developed an axillary recurrence and in the second group this was 25/1229 (2.0%) respectively. No significant difference between groups regarding axillary recurrence, sentinel node status and distant metastasis was found.

CONCLUSION

Axillary recurrence rate is not influenced by the inability to remove all sentinel nodes during surgery that have been identified preoperatively by scintigraphy.

A dual-modal magnetic nanoparticle probe for preoperative and intraoperative mapping of sentinel lymph nodes by magnetic resonance and near infrared fluorescence imaging

The ability to reliably detect sentinel lymph nodes for sentinel lymph node biopsy and lymphadenectomy is important in clinical management of patients with metastatic cancers. However, the traditional sentinel lymph node mapping with visible dyes is limited by the penetration depth of light and fast clearance of the dyes. On the other hand, sentinel lymph node mapping with radionucleotide technique has intrinsically low spatial resolution and does not provide anatomic details in the sentinel lymph node mapping procedure. This work reports the development of a dual modality imaging probe with magnetic resonance and near infrared imaging capabilities for sentinel lymph node mapping using magnetic iron oxide nanoparticles (10 nm core size) conjugated with a near infrared molecule with emission at 830 nm. Accumulation of magnetic iron oxide nanoparticles in sentinel lymph nodes leads to strong T2 weighted magnetic resonance imaging contrast that can be potentially used for preoperative localization of sentinel lymph nodes, while conjugated near infrared molecules provide optical imaging tracking of lymph nodes with a high signal to background ratio. The new magnetic nanoparticle based dual imaging probe exhibits a significant longer lymph node retention time. Near infrared signals from nanoparticle conjugated near infrared dyes last up to 60 min in sentinel lymph node compared to that of 25 min for the free near infrared dyes in a mouse model. Furthermore, axillary lymph nodes, in addition to sentinel lymph nodes, can be also visualized with this probe, given its slow clearance and sufficient sensitivity. Therefore, this new dual modality imaging probe with the tissue penetration and sensitive detection of sentinel lymph nodes can be applied for preoperative survey of lymph nodes with magnetic resonance imaging and allows intraoperative sentinel lymph node mapping using near infrared optical devices.

Fluorescence imaging and whole-body biodistribution of near-infrared-emitting quantum dots after subcutaneous injection for regional lymph node mapping in mice

PURPOSE

This study compares fluorescence imaging to mass spectroscopy (inductively coupled plasma-mass spectroscopy, ICP-MS) for detection of quantum dots (QDs) in sentinel lymph node (LN) mapping of breast cancer.

PROCEDURES

We study the accumulation of near-infrared-emitting QDs into regional LNs and their whole-body biodistribution in mice after subcutaneous injection, using in vivo fluorescence imaging and ex vivo elemental analysis by ICP-MS.

RESULTS

We show that the QD accumulation in regional LNs is detectable by fluorescence imaging as early as 5 min post-delivery. Their concentration reaches a maximum at 4 h then decreases over a 10-day observation period. These data are confirmed by ICP-MS. The QD uptake in other organs, assessed by ICP-MS, increases steadily over time; however, its overall level remains rather low.

CONCLUSIONS

Fluorescence imaging can be used as a non-invasive alternative to ICP-MS to follow the QD accumulation kinetics into regional LNs.

Pre-operative lymphoscintigraphy before sentinel lymph node biopsy for breast cancer

Pre-operative lymphoscintigram for axillary sentinel lymph node biopsy (SLNB) may not be required for successful SLNB. The 117 consecutive patients who underwent SLNB had pre-operative lymphoscintigraphy. The operating surgeon was blinded to the results of the lymphoscintigram before SLNB. After SLNB was complete, the surgeon was unblinded to the results of the lymphoscintigram; re-exploration carried out if more nodes were predicted on the lymphoscintigram. 116 patients (99%) had successful SLNB before unblinding. In 85 patients (73%), operative findings corresponded with scintigraphic findings. In 26 patients (22%), the lymphoscintigram predicted more sentinel nodes than had been found; further nodes were identified and excised in only 4 patients (3%). None were positive for cancer. SLNB was successful in 99% of cases without pre-operative lymphoscintigraphy. Only 3% of patients had further nodes identified as a result of the lymphoscintigram. Pre-operative lymphoscintigraphy does not improve the ability to perform axillary SLNB during breast cancer surgery.

The sentinel node in breast cancer

Biopsy of the sentinel lymph node now forms part of routine management in many centres dealing with early stage breast cancer. This article seeks to discuss developments over the past number of years and to summarise current practice.

Quantum dots in axillary lymph node mapping: biodistribution study in healthy mice

Background

Breast cancer is the first cause of cancer death among women and its incidence doubled in the last two decades. Several approaches for the treatment of these cancers have been developed. The axillary lymph node dissection (ALND) leads to numerous morbidity complications and is now advantageously replaced by the dissection and the biopsy of the sentinel lymph node. Although this approach has strong advantages, it has its own limitations which are manipulation of radioactive products and possible anaphylactic reactions to the dye. As recently proposed, these limitations could in principle be by-passed if semiconductor nanoparticles (quantum dots or QDs) were used as fluorescent contrast agents for the in vivo imaging of SLN. QDs are fluorescent nanoparticles with unique optical properties like strong resistance to photobleaching, size dependent emission wavelength, large molar extinction coefficient, and good quantum yield.

Methods

CdSe/ZnS core/shell QDs emitting around 655 nm were used in our studies. 20 μL of 1 μM (20 pmol) QDs solution were injected subcutaneously in the anterior paw of healthy nude mice and the axillary lymph node (ALN) was identified visually after injection of a blue dye. In vivo fluorescence spectroscopy was performed on ALN before the mice were sacrificed at 5, 15, 30, 60 min and 24 h after QDs injection. ALN and all other organs were removed, cryosectioned and observed in fluorescence microscopy. The organs were then chemically made soluble to extract QDs. Plasmatic, urinary and fecal fluorescence levels were measured.

Results

QDs were detected in ALN as soon as 5 min and up to 24 h after the injection. The maximum amount of QDs in the ALN was detected 60 min after the injection and corresponds to 2.42% of the injected dose. Most of the injected QDs remained at the injection site. No QDs were detected in other tissues, plasma, urine and feces.

Conclusion

Effective and rapid (few minutes) detection of sentinel lymph node using fluorescent imaging of quantum dots was demonstrated. This work was done using very low doses of injected QDs and the detection was done using a minimally invasive method.

Implications of transaxillary breast augmentation: lifetime probability of breast cancer development and sentinel node mapping interference

After the "fifth-generation" breast implants with ultracohesive silicone gel technology are introduced, the Food and Drug Administration (FDA) will sooner or later retire the ban on the use of these devices in the United States. When this happens, the plastic surgery community must be prepared to face a massive demand for reoperations to change saline-filled breast implants because cohesive gel devices have the potential to provide a more natural breast shape, to minimize the risk of postoperative rippling, and to provide a greater degree of safety if the implant loses its integrity. Despite these advantages and extensive use throughout the rest of the world during the ban in the United States, silicone implants also have disadvantages. One drawback is that transaxillary breast augmentation with more "rigid" gel-filled implants may produce trauma to the armpit, may interfere with sentinel node mapping for breast cancer treatment, and may have future medicolegal implications.

Does Failure to Visualize a Sentinel Node on Preoperative Lymphoscintigraphy Predict a Greater Likelihood of Axillary Lymph Node Positivity?

BACKGROUND

Sentinel lymph node (SLN) mapping has become the standard of care for axillary staging in women with early-stage breast cancer. The purpose of the study was to investigate the hypothesis that nonvisualization of SLN on lymphoscintigraphy (LSG) predicts a subset of patients at risk of having a substantial burden of axillary tumor as evidenced by higher rate of lymph node involvement.

STUDY DESIGN

We retrospectively reviewed the records of 1,500 patients who underwent dual-tracer SLN mapping for breast cancer between 1999 and 2004. LSG were reported as negative or positive.

RESULTS

Ninety-one percent had axillary SLN(s) identified on LSG imaging. In 133 of 134 (99.3%) patients with a negative LSG, SLN(s) was identified intraoperatively either by blue dye or hand-held gamma detection. SLN was positive in 28.4% of LSG nonvisualized group and was positive in 29.1% of LSG visualized group (p>0.05). A significantly higher percentage of women older than 50 years of age had nonvisualization of SLN (p<0.0001). Body mass index (calculated as kg/m2) was >30 in 42.5% of LSG nonvisualized group and in 26.3% in LSG visualized group (p<0.0001).

CONCLUSIONS

Failure to demonstrate axillary uptake by LSG appears to be related to technical factors and patient-related factors, such as body mass index and older age, but does not adversely affect SLN identification. The equivalent rate of positive SLNs in patients with a positive or negative LSG supports the null hypothesis that "failure to visualize" on LSG does not identify a subset of patients at higher risk of being axillary lymph node positive.

Preoperative lymphoscintigraphy predicts the successful identification but is not necessary in sentinel lymph nodes biopsy in breast cancer

BACKGROUND

Although preoperative lymphoscintigraphy in sentinel lymph node biopsy (SLNB) for breast cancer patients is undergone commonly, its clinical significance remains controversial.

METHODS

We retrospectively analyzed our database that contained 636 consecutive breast cancer patients who received preoperative lymphoscintigraphy before SLNB.

RESULTS

The sentinel lymph nodes (SLNs) of 86.5% of patients were well imaged by lymphoscintigraphy, and SLN were located extra-axilla in 5.3% patients. The visualization of SLN in lymphoscintigraphy was not associated with histopathologic type, location, and stage of primary tumor, as well as the time interval from injection of radiocolloid to surgery. The negative lymphoscintigraphy results were associated with excision ;biopsy before injection of radiocolloid and positive axillary node statues. The SLN was successfully detected in 625 (98.3%) enrolled patients. Failure of surgical identification of axillary SLN was associated with whether hot spot was imaged by lymphoscintigraphy. However, we identified axillary SLN in 90 (90.9%) out of 99 patients with negative axillary findings in lymphoscintigram. The false negative rate of SLNB in our study was 16.0% (15 of 94) among patients of training group, and there was no significant difference in the false negative rate between patients who had axillary hot spot in lymphoscintigram and those who had not (P = .273).

CONCLUSIONS

Visualization of SLN in preoperative lymphoscintigraphy predicted the successful SLN identification. However, it was less informative for the location of SLN during operation. Considering the complexity, time consumed, and cost, lymphoscintigraphy should at present be undergone for investigation purposes only.

[Sentinel node detection applied to breast cancer: 2007 update]

The technique of detection and resection of the sentinel lymph node applied to early breast cancer management aims to spare the patient with a low risk of lymph node involvement an unnecessary axillary lymphadenectomy. This innovating technique lies on the double hypothesis of an accuracy to predict non sentinel lymph node status and to induce a lower morbidity when compared with axillary lymphadenectomy. This multidisciplinary technique depends on surgeons, nuclear physicians and pathologists. In practice sentinel lymph nodes are detected thanks to two types of tracers, the Blue and the colloids marked with technetium, harvested by the surgeon guided by the blue lymphatic channel and the use of a gamma probe detection, analyzed by the pathologist according to a particular procedure with the concept of serial slices, and possibly immuno histo chemistry. The objectives of this review are to specify the state of knowledge concerning the different steps: detection, surgical resection and the pathological analysis of the sentinels lymph nodes and to focus on validated and controversial indications, and on the main ongoing trials.