Impact of axillary nodal metastases on lymphatic mapping and sentinel lymph node identification rate in patients with early stage breast cancer

Quantum dot-NanoLuc bioluminescence resonance energy transfer enables tumor imaging and lymph node mapping in vivo

A small luciferase protein (Nluc) was conjugated to QDs as a bioluminescence resonance energy transfer (BRET) pair. The conjugate showed 76% BRET efficiency and lymph node mapping was successfully performed. The cRGD peptide was conjugated to QD-Nluc for tumor targeting. The self-illuminating QD-Nluc showed excellent energy transfer in a living system and offered an optimal tumor-to-background ratio (>85).

Tracer-cocktail injections for combined pre- and intraoperative multimodal imaging of lymph nodes in a spontaneous mouse prostate tumor model

To improve surgical guidance toward prostate draining lymph nodes, we investigate the potential of intraoperative fluorescence imaging and combined pre- and intraoperative multimodality imaging approaches. Transgenic adenocarcinoma mouse prostate mice with spontaneous prostate tumors are injected intratumorally with: 1. a cocktail of patent blue (Pb) and indocyanine green (ICG); 2. a cocktail of albumin radiocolloids (99mTc-NanoColl), Pb, and ICG; or 3. a cocktail of radiolabeled albumin (99mTc-Vasculosis), Pb, and ICG. The distribution of these imaging agents over the lymph nodes (LNs) are studied at different time points after injection. We find that at 60-min postinjection, ICG significantly improves the detection of the LNs compared to Pb, 53 versus 7%, respectively. Moreover, a cocktail of ICG and 99mTc-NanoColl improves the fluorescent detection rate to 86%, equalling that of the clinically applied 99mTc-NanoColl. A similar overlap is observed in our initial clinical pilot data. Fluorescent detection of the LNs using a ICG with 99mTc-Vasculosis gives similar results as "free" ICG (58%; 60 min). A 99mTc-NanoColl, Pb, and cocktail ICG enriches the standard 99mTc-NanoColl approach by adding optical detection of the sentinel lymph nodes. Furthermore, this approach improves fluorescent-based guidance and enables both accurate surgical planning and intraoperative detection, based on a single injection.

Sentinel node identification rate and nodal involvement in the EORTC 10981-22023 AMAROS trial

Background

The randomized EORTC 10981-22023 AMAROS trial investigates whether breast cancer patients with a tumor-positive sentinel node biopsy (SNB) are best treated with an axillary lymph node dissection (ALND) or axillary radiotherapy (ART). The aim of the current substudy was to evaluate the identification rate and the nodal involvement.

Methods

The first 2,000 patients participating in the AMAROS trial were evaluated. Associations between the identification rate and technical, patient-, and tumor-related factors were evaluated. The outcome of the SNB procedure and potential further nodal involvement was assessed.

Results

In 65 patients, the sentinel node could not be identified. As a result, the sentinel node identification rate was 97% (1,888 of 1,953). Variables affecting the success rate were age, pathological tumor size, histology, year of accrual, and method of detection. The SNB results of 65% of the patients (n = 1,220) were negative and the patients underwent no further axillary treatment. The SNB results were positive in 34% of the patients (n = 647), including macrometastases (n = 409, 63%), micrometastases (n = 161, 25%), and isolated tumor cells (n = 77, 12%). Further nodal involvement in patients with macrometastases, micrometastases, and isolated tumor cells undergoing an ALND was 41, 18, and 18%, respectively.

Conclusions

With a 97% detection rate in this prospective international multicenter study, the SNB procedure is highly effective, especially when the combined method is used. Further nodal involvement in patients with micrometastases and isolated tumor cells in the sentinel node was similar—both were 18%.

In vivo imaging of sentinel nodes using fluorescent silica nanoparticles in living mice

PURPOSE

We examine the feasibility of fluorescent imaging system for sentinel lymph node detection by using functionalized silica nanoparticles.

MATERIALS AND METHODS

We developed a functionalized RITC-SiO(2) nanoparticles containing fluorescent dye, C(28)H(31)N(2)O(3)Cl (rhodamine B isothiocyanate) inside, and subsequently synthesized (68)Ga-NOTA-RITC-SiO(2) nanoparticles.

RESULTS

At 5 min after RITC-doped silica nanoparticles injection, fluorescent signals were shown in both right axillary lymph node (ALN) and injection site of living mice. Fluorescent signals were also observed at these locations in a biodistribution study. In addition, fluorescence was detected in frozen ALN sections microscopically. The percentages of doses injected per gram of tissue of axillary and brachial lymph nodes near footpad treated with (68)Ga-NOTA-RITC-SiO(2) nanoparticles were 308.3 +/- 3.4 and 41.5 +/- 6.1, respectively. Little (68)Ga radioactivity was found in other organs.

CONCLUSION

Our data provide strong evidence that functionalized silica nanoparticles has a promising potential as organic lymphatic tracer in biomedical imaging such as pre- and intraoperative surgical guidance.

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.

Impact of Patient- and Disease-Specific Factors on SLNB in Breast Cancer Patients. Are Current Guidelines Justified?

BACKGROUND

The evidence on which to base guidelines for sentinel lymph node biopsy (SLNB) in breast cancer is still limited. In order to facilitate the further implementation of renewed guidelines, we evaluated patient- and disease-specific factors for their impact on the results of SLNB.

MATERIALS AND METHODS

Prospective data acquisition from patients undergoing surgery for primary invasive breast cancer was performed. All patients underwent SLNB using the radiocolloid or the combined technique. The association of patient- and disease-specific factors to detection rate and false-negative rate was calculated using univariate and multivariate analyses (P < 0.05 considered as significant). Calculation of the false-negative rate was based on patients who underwent a backup axillary dissection.

RESULTS

Among 455 consecutively enrolled patients, a significant inverse association to the detection rate was found for extracapsular extension of non-SLN metastases, body mass index (BMI), number of involved lymph nodes, pT category, tumor size, and age. A significant association to the false-negative rate to identify macrometastases was found for pT category, tumor size, and grading. Other factors, such as prior surgery, multicentric tumor growth, or vascular invasion, showed no influence. A cut-point analysis revealed that a tumor size of 2 cm separated the collective of patients with the highest significance in regard to the false-negative rate (9% vs. 25%).

CONCLUSION

Our results indicate that SLNB can be safely used in elderly and obese patients with multicentric tumors and those having undergone prior surgery for benign breast disease. However, the method should be applied with caution in patients with tumors larger than 2 cm.

Successful Internal Mammary Visualization With Periareolar Injections of Tc-99m Antimony Sulfur Colloid in Sentinel Node Breast Lymphoscintigraphy

PURPOSE

The subareolar and periareolar injection techniques result in higher detection rates and do not require tumor localization in impalpable lesions when compared with the peritumoral technique. One of the main criticisms, however, is the widely reported inability to detect internal mammary nodes. This contrasts with our clinical experience using Tc-99m antimony sulfur colloid, in which internal mammary nodes are commonly seen.

METHODS

A retrospective analysis of 241 patients over 38 months was performed to investigate the ability of our periareolar injection technique to detect internal mammary lymph node drainage in breast cancer sentinel node lymphoscintigraphy. Four injections of 5 to 10 MBq (0.14-0.27 mCi) Tc-99m antimony sulfur colloid were administered on the day of surgery followed by massage and imaging. The radioisotope was suspended in 0.1 mL with a 0.5-mL air lock. Each injection was performed over 2 seconds with a 25-gauge needle at a depth of 1.1 to 1.3 cm. Patients whose records could not be retrieved or who underwent an injection technique apart from periareolar or peritumoral were removed from the analysis.

RESULTS

One hundred thirty-three patients underwent the periareolar technique, 72 patients underwent the peritumoral technique, and 36 patients were excluded from the analysis. Internal mammary drainage was seen in 24 of 133 (18.0%) patients, of which 12 (9%) were seen only in the internal mammary chain. This is much higher than previous studies quoting 0.0% to 4.3% and is similar to previously reported rates using the peritumoral technique.

CONCLUSIONS

Our periareolar injection technique using Tc-99m antimony sulfur colloid is able to detect internal mammary lymph nodes in at least 18.0% of patients.

The influence of wire localisation for non-palpable breast lesions on visualisation of the sentinel node

PURPOSE

In our clinic, patients with occult breast lesions are treated with a sentinel node biopsy combined with wire-guided tumour excision. The aim of this retrospective study was to determine the influence of the sequence of wire localisation and sentinel node procedure on visualisation of the sentinel node.

METHODS

A total of 136 patients had a wire-guided tumour excision combined with a sentinel node procedure. Sixty-six patients had guide wire localisation prior to the sentinel node procedure. Seventy patients had sentinel node visualisation before insertion of the guide wire.

RESULTS

The sentinel node was visualised in 41 (62%) of the patients who first underwent guide wire localisation. In the group of patients who underwent visualisation of the sentinel node before placement of the guide wire, the sentinel node was visualised in 62 (89%). This is a significant difference in visualisation (p<0.001).

CONCLUSION

This study shows that guide wire localisation prior to the sentinel node procedure negatively influences visualisation of the sentinel node.

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

The aim of this study was to identify the variables associated with successful peroperative sentinel lymph node (SLN) localization. We studied 201 patients with T1, T2, N0 invasive breast cancer who underwent a SLN procedure from 1999 to 2003. Of these 201 patients, 55 underwent peritumoral and 146 underwent periareolar radioisotope injection before the blue dye injection. All patients were operated on by breast conservative surgery and axillary dissection after SLN biopsy. Age, weight, menopausal status, previous biopsy, localization of the tumor, results of lymphoscintigraphy, site of radiotracer injection, tumor size, tumor grade, experience of surgeons, and the number of invaded axillary nodes were analyzed to determine whether they had any significant correlation with successful identification of SLN. Variables found to have a statistically significant influence on the SLN identification rate and on preoperative lymphoscintigraphy identification were introduced into a univariate and multivariate logistic regression model. In multivariate analysis, successful lymphoscintigraphy (P < 0.0001) and the absence of metastatic axillary nodes (P < 0.005) were associated with successful identification of SLNs. The peritumoral injection of radiotracer (P < 0.001), patient age > 60 years (P < 0.003), and localization of the tumor in the upper outer quadrant (P < 0.004) were associated with failure of lymphoscintigraphic visualization of SLN. The technique of SLN detection thus appears to be better for patients with low risk of invaded axillary lymph nodes.

The sentinel node in breast cancer: an update

There has been rapid acceptance of sentinel lymph node biopsy into the management of breast cancer over the past 10 years. This article seeks to highlight the controversies and to summarise its current status.