SPECT/CT for preoperative sentinel node localization

The EANM clinical and technical guidelines for lymphoscintigraphy and sentinel node localization in gynaecological cancers

The accurate harvesting of a sentinel node in gynaecological cancer (i.e. vaginal, vulvar, cervical, endometrial or ovarian cancer) includes a sequence of procedures with components from different medical specialities (nuclear medicine, radiology, surgical oncology and pathology). These guidelines are divided into sectione entitled: Purpose, Background information and definitions, Clinical indications and contraindications for SLN detection, Procedures (in the nuclear medicine department, in the surgical suite, and for radiation dosimetry), and Issues requiring further clarification. The guidelines were prepared for nuclear medicine physicians. The intention is to offer assistance in optimizing the diagnostic information that can currently be obtained from sentinel lymph node procedures. If specific recommendations given cannot be based on evidence from original scientific studies, referral is made to "general consensus" and similar expressions. The recommendations are designed to assist in the practice of referral to, and the performance, interpretation and reporting of all steps of the sentinel node procedure in the hope of setting state-of-the-art standards for high-quality evaluation of possible metastatic spread to the lymphatic system in gynaecological cancer. The final result has been discussed by a group of distinguished experts from the EANM Oncology Committee and the European Society of Gynaecological Oncology (ESGO). The document has been endorsed by the SNMMI Board.

Management of regional metastatic disease in head and neck cutaneous malignancy. 2. Cutaneous malignant melanoma

This is the second of 2 articles giving an overview of the current evidence for management of the neck and parotid in cutaneous cancers of the head and neck. We discuss cutaneous malignant melanoma and review the latest evidence for management of the regional nodes.

Utility of SPECT/CT for periparotid sentinel lymph node mapping in the surgical management of head and neck melanoma

PURPOSE

Sentinel lymph node (SLN) biopsy is instrumental in staging and treatment of cutaneous melanoma. SPECT/CT, single-photon emission computed tomography (SPECT) integrated with computed tomography (CT), increases the accuracy of SLN mapping to improve surgical planning. SPECT/CT can correct for signal scatter to prevent masking, which is especially common in the head and neck. For periparotid lymph nodes SPECT/CT may improve localization of SLNs compared to lymphoscintigraphy.

MATERIALS/METHODS

Hospital charts were reviewed for 14 patients with melanoma and suspected lymphatic drainage to the parotid region who received lymphoscintigraphy followed by SPECT/CT prior to surgical excision and SLN.

RESULTS

Overall, SPECT/CT provided data, which changed management in 57% of patients.

CONCLUSIONS

Fifty-seven percent of our patients benefited from use of SPECT/CT. The distinction between level II and parotid sentinel lymph nodes was clearly identified through SPECT/CT images. We believe that patients with melanoma draining to the parotid region would benefit from SPECT/CT SLN mapping.

Is There a Place for Sentinel Technique in Treatment of Vaginal Cancer?: Feasibility, Clinical Experience, and Results

Objective

To evaluate the clinical feasibility of sentinel lymph node (SLN) technique and the role of single-photon emission computed tomography with CT (SPECT/CT) compared to lymphoscintigraphy for detection of SLN in vaginal cancer.

Methods

The study was performed in a prospective, unicentric setting. Patients with vaginal carcinoma were scheduled for surgery and SLN labeling by peritumoral injection of 10-MBq technetium Tc 99m nanocolloid and patent blue. After 30 minutes, lymphoscintigraphy and SPECT/CT were carried out. We evaluated the number of SLNs in lymphoscintigraphy, SPECT/CT, and intraoperative histology of SLN and non-SLN as well as the impact of these results to therapeutic approach.

Results

Between January 2009 and December 2012, the SLN technique was used for 7 of 11 patients treated due to vaginal cancer. Detection rate was 100% (7/7). Lymphoscintigraphy and SPECT/CT showed at least one SLN in each patient. Lymphoscintigraphy detected 2.6 SLNs (range, 2–4 SLNs) per patient compared to 4.3 SLNs (range, 2–8 SLNs) in SPECT/CT (P= 0.053). Sentinel lymph nodes were detected in all patients during surgery with a mean number of 4.3 (range, 1–5). Pelvic SLNs were detected in all 6 patients with infiltration of middle or proximal vaginal third (100%). If the distal vaginal third was additional (3/7 patients) or exclusively (1/7 patients) infiltrated, the inguinal SLN detection rate was 33% and 100%, respectively. All patients with nodal metastases had at least one SLN positive for tumor. There were no false negatives. In 2 (29%) of 7 patients, treatment approach was modified owing to affected SLN.

Conclusion

The SLN technique was favorably used in vaginal cancer in this series. It assists in identifying an inguinal and/or pelvic lymphatic drainage. When performed accurately (technetium Tc 99m nanocolloid, lymphoscintigraphy and/or SPECT/CT, blue dye), this technique predicts regional nodal status. This allows tumor stage–adjusted therapy. Single photon emission computed tomography/CT improves preoperative planning and facilitates detection, thus enhancing the clinical value of the SLN technique and improving the oncologic safety of surgery.

[Utility of single photon emission computed tomography-computed tomography in selective sentinel lymph node biopsy in patients with melanoma]

OBJECTIVE

To assess the contribution of SPECT-CT lymphoscintigraphy in selective sentinel lymph node biopsy (SLNB) in patients with newly diagnosed malignant melanoma.

MATERIAL AND METHODS

A prospective study was made between July 2009 and October 2010. It included 63 patients diagnosed with melanoma (32 men and 31 women) with mean age of 55 years (range: 25-88) and inclusion criteria for SLNB. The melanomas were located as follows: 28 in trunk, 5 in head and neck, 16 in upper limbs and 17 in lower limbs. Three patients had two melanomas. Preoperative lymphoscintigraphy was performed after pericicatricial/perilesional injection of 74MBq of (99m)Tc-labeled nanocolloid human serum albumin, obtaining early planar images, late whole body study and sectorial images and SPECT-CT in the area of interest. Planar scintigraphy findings were compared with SPECT-CT.

RESULTS

The sentinel node (SN) was localized by planar imaging in 62/63 (98%) of patients. SPECT-CT study located the SN in all the patients with a detection rate of 100%. The number of SNs detected with SPECT-CT was higher than with the planar study in 27 patients. The SPECT-CT provided additional information (change in location and/or in its accuracy in the localization of location uncertain SN) in 14/63 (22.2%) patients, involving changes in the surgical approach and lymph node staging.

CONCLUSION

SPECT-CT detects a higher number of SN than planar lymphoscintigraphy in patients with melanoma. Its contribution is more relevant in the melanomas located on the trunk, head and neck. SPECT-CT modified the SN location by 22% compared to planar scan findings, facilitating a correct surgical approach.

Sentinel node navigation surgery in patients with early gastric cancer

Clinical application of sentinel node (SN) mapping in patients with early gastric cancer has been a controversial issue for years. However, a recent meta-analysis and a prospective multicenter trial of SN mapping for early gastric cancer have shown acceptable SN detection rates and accuracy of determination of lymph node status. A dual-tracer method that utilizes radioactive colloids and blue dyes is currently considered the most reliable method for the stable detection of SNs in patients with early gastric cancer. However, new technologies such as indocyanine green infrared or fluorescence imaging might revolutionize the SN mapping procedures in gastric cancer. For early-stage gastric cancer such as cT1N0, for which a better prognosis can be potentially achieved through conventional surgical approaches, the establishment of individualized, minimally invasive treatments that may retain the patients' quality of life should be the next surgical challenge. Although there are many unresolved technical issues, laparoscopic SN biopsy with laparoscopic minimized gastrectomy or endoscopic mucosal resection/endoscopic submucosal dissection could be a promising strategy to achieve this goal.

Added value of the hybrid tracer indocyanine green-99mTc-nanocolloid for sentinel node biopsy in a series of patients with different lymphatic drainage patterns

INTRODUCTION

Indocyanine green (ICG)-(99m)Tc-nanocolloid is a novel hybrid fluorescent radioactive tracer for sentinel node (SN) biopsy. This study has aimed to evaluate the added value of this novel versatile tracer in a series of patients with different malignancies.

MATERIAL AND METHODS

Twenty patients (with penile carcinoma, oral cavity tumors, melanoma) were consecutively included between March-May 2012. Planar lymphoscintigraphy was performed 15 min and 2h after injection of ICG-(99m)Tc-nanocolloid followed by SPECT/CT. Blue dye (1 ml) was injected in 14 patients in surgery room. Intraoperatively, SNs were localized using a gamma probe and visualized by optical SN-detection using blue dye and fluorescence imaging. Finally, a portable gamma camera was used to confirm complete SN removal.

RESULTS

At least one SN was identified by SPECT/CT in all patients. All SNs (total 68, 100%) were excised using a combination of radio- and fluorescence guidance: 89.7% were intraoperatively localized with the gamma probe. The remaining SNs, located near the injection site, were localized using fluorescence imaging. During the surgery, 97% of the SNs were fluorescent while only 39.2% were stained blue. Ex vivo, all SNs were both radioactive and fluorescent. The SN was positive in 5 patients.

CONCLUSION

Synchronous radio- and fluorescence guided SN biopsy is feasible using ICG-(99m)Tc-nanocolloid. This hybrid approach combines the beneficial properties of both modalities. Adding fluorescence imaging improves optical SN detection compared to blue dye. It has been shown to be especially useful in the localization of SNs near the injection site.

Use of SPECT/CT for improved sentinel lymph node localization in endometrial cancer

OBJECTIVE

To assess the usefulness of adding SPECT/CT to planar images for pre-surgical sentinel lymph node (SLN) identification in endometrial cancer (EC), a technique that could have an important clinical impact on the staging, treatment, and prognosis of EC patients.

METHODS

We compared the planar and SPECT/CT lymphoscintigraphic images of 44 patients with high-risk EC who underwent sentinel lymph node procedure (SLN) using an injection technique recently developed at our center known as TUMIR (Transvaginal Ultrasound Myometrial Injection of Radiotracer). 148 MBq (4 mCi) of 99mTc-nanocolloid were injected, guided by transvaginal ultrasound imaging. Planar and SPECT/CT images were performed in all 44 patients.

RESULTS

SLNs were seen on planar images in 32 cases (73%) and in 34 cases (77%) using SPECT/CT. A total of 88 SLNs were depicted by planar lymphoscintigraphy while SPECT/CT visualized a total of 110 SLNs. SPECT/CT changed the assessment of the SLNs visualized in planar lymphoscintigraphy in 26 cases, either by modifying the number and/or the location of the SLNs detected. External iliac chain was the most frequent location of SLN detection (71%) in the 34 cases. Fifteen of these patients (44%) showed para-aortic SLNs. One case had exclusive para-aortic drainage (3%) that was only visualized by SPECT/CT. In another case, SPECT/CT was able to localize the only pelvic metastatic lymph node not visualized by planar images.

CONCLUSIONS

SPECT/CT combined with planar imaging improves preoperative SLN detection and provides valuable anatomic information that enhances the presurgical stage of the SLN technique in endometrial cancer.

Malignant melanoma

Nuclear medicine plays an essential role in the correct staging of patients suffering from melanoma. Both sentinel lymph node biopsy (SLNB) and positron emission tomography (PET) represent its main diagnostic tools. SLNB is the choice procedure for lymphatic regional staging of these patients, including the result of this technique in the 2002 American Joint Cancer Committee melanoma staging. SLNB sensitivity is superior than PET/CT for the detection of lymphatic micrometastases in early stages of the disease. PET/CT is mainly used in confirming clinical metastases suspected, detection of recurrences, and recurrence restaging. PET/CT has also shown superiority against conventional diagnostic methods in the detection of distant metastases, being able to detect illness even six months earlier than those methods.

Combined analysis of phase III trials evaluating [⁹⁹mTc]tilmanocept and vital blue dye for identification of sentinel lymph nodes in clinically node-negative cutaneous melanoma

Background

[^99mTc]Tilmanocept is a CD206 receptor-targeted radiopharmaceutical designed for sentinel lymph node (SLN) identification. Two nearly identical nonrandomized phase III trials compared [^99mTc]tilmanocept to vital blue dye.

Methods

Patients received [^99mTc]tilmanocept and blue dye. SLNs identified intraoperatively as radioactive and/or blue were excised and histologically examined. The primary end point, concordance, was the proportion of blue nodes detected by [^99mTc]tilmanocept; 90 % concordance was the prespecified minimum concordance level. Reverse concordance, the proportion of radioactive nodes detected by blue dye, was also calculated. The prospective statistical plan combined the data from both trials.

Results

Fifteen centers contributed 154 melanoma patients who were injected with both agents and were intraoperatively evaluated. Intraoperatively, 232 of 235 blue nodes were detected by [^99mTc]tilmanocept, for 98.7 % concordance (p < 0.001). [^99mTc]Tilmanocept detected 364 nodes, for 63.7 % reverse concordance (232 of 364 nodes). [^99mTc]Tilmanocept detected at least one node in more patients (n = 150) than blue dye (n = 138, p = 0.002). In 135 of 138 patients with at least one blue node, all blue nodes were radioactive. Melanoma was identified in the SLNs of 22.1 % of patients; all 45 melanoma-positive SLNs were detected by [^99mTc]tilmanocept, whereas blue dye detected only 36 (80 %) of 45 (p = 0.004). No positive SLNs were detected exclusively by blue dye. Four of 34 node-positive patients were identified only by [^99mTc]tilmanocept, so 4 (2.6 %) of 154 patients were correctly staged only by [^99mTc]tilmanocept. No serious adverse events were attributed to [^99mTc]tilmanocept.

Conclusions

[^99mTc]Tilmanocept met the prespecified concordance primary end point, identifying 98.7 % of blue nodes. It identified more SLNs in more patients, and identified more melanoma-containing nodes than blue dye.

Decisive role of SPECT/CT in localization of unusual periscapular sentinel nodes in patients with posterior trunk melanoma: three illustrative cases and a review of the literature

Sentinel node mapping is widely applied in patients with melanoma. Although this type of skin cancer usually drains to the standard regional nodal basins, some patients have drainage to an unpredicted site. Nodes lying along a lymphatic channel, between the primary melanoma site and a common basin, are often called interval, in-transit, ectopic, intercalated, or aberrant nodes. They must be considered sentinel lymph nodes because they receive direct lymphatic drainage from a primary tumor site. Most investigators agree that interval sentinel nodes should be harvested; however, the management of melanoma patients with an involved interval sentinel node without established metastasis in the regional basin downstream is controversial. New and innovating technologies have improved nuclear medicine images, including single-photon emission computed tomography/computed tomography (SPECT/CT), a multimodal technique that fuses the radioactivity distribution detected by SPECT with the anatomic information harvested by CT. SPECT/CT does not replace the conventional planar images; it should be considered as a complementary modality for the search of sentinel lymph nodes. We report three illustrative cases that underline the decisive role of SPECT/CT with two-dimensional and three-dimensional reconstruction images to localize the uncommon periscapular sentinel nodes in patients with melanoma of the posterior trunk. The use of this image fusion technique on these patients leads to improved preoperative visualization of the sentinel nodes, may help identify additional periscapular interval sentinel nodes, and enables precise localization of the nodes with their surrounding anatomic structures. The cases are discussed together with a review of the literature.

Sentinel node mapping for breast cancer: current situation

Axillary node status is a major prognostic factor in early-stage disease. Traditional staging needs levels I and II axillary lymph node dissection. Axillary involvement is found in 10%–30% of patients with T1 (<2 cm) tumours. Sentinel lymph node biopsy is a minimal invasive method of checking the potential nodal involvement. It is based on the assumption of an orderly progression of lymph node invasion by metastatic cells from tumour site. Thus, when sentinel node is free of metastases the remaining nodes are free, too (with a false negative rate lesser than 5%). Moreover, Randomized trials demonstrated a marked reduction of complications associated with the sentinel lymph node biopsy when compared with axillary lymph node dissection. Currently, the sentinel node biopsy procedure is recognized as the standard treatment for stages I and II. In these stages, this approach has a positive node rate similar to those observed after lymphadenectomy, a significant decrease in morbidity and similar nodal relapse rates at 5 years. In this review, the indications and contraindications of the sentinel node biopsy are summarized and the methodological aspects discussed. Finally, the new technologic and histologic developments allow to develop a more accurate and refinate technique that can achieve virtually the identification of 100% of sentinel nodes and reduce the false negative rate.

Sentinel node navigation surgery in early-stage esophageal cancer

The sentinel node (SN) concept has revolutionized the surgical staging of both melanoma and breast cancer over the past two decades. However, the validity of the SN hypothesis has been controversial for esophageal cancer, because SN mapping for esophageal cancer is technically complicated, and the number of early-stage esophageal cancer is very limited. Nevertheless previous studies nicely demonstrated that SN mapping may be feasible in patients with early-stage esophageal cancer. Transthoracic extended esophagectomy with three-field radical lymph node dissection has been recognized as a curative procedure for thoracic esophageal cancer in Japan. However, uniform application of this highly invasive procedure might increase the morbidity and markedly reduce the quality of life (QOL) after surgery. Although further accumulation of evidence based on multicenter clinical trials using a standard protocol is needed, SN mapping and SN navigation surgery would provide significant information to perform individualized selective lymphadenectomy which might reduce the morbidity and retain the patients' QOL. In addition, technical innovation including the development of new tracers is expected to confirm the accuracy and reliability of SN mapping in esophageal cancer.

Comparing the hybrid fluorescent-radioactive tracer indocyanine green-99mTc-nanocolloid with 99mTc-nanocolloid for sentinel node identification: a validation study using lymphoscintigraphy and SPECT/CT

The purpose of this study was to compare the lymphoscintigraphic drainage patterns of a hybrid sentinel node tracer consisting of the fluorescent dye indocyanine green (ICG) and (99m)Tc-nanocolloid with the drainage pattern of (99m)Tc-nanocolloid alone, the current standard tracer in many European countries.

METHODS

Twenty-five patients with a melanoma in the head and neck region (n = 10), a melanoma on the trunk (n = 6), or penile carcinoma (n = 9) who were scheduled for sentinel node biopsy were prospectively included. First, the standard (99m)Tc-nanocolloid procedure was performed. After injection at the lesion site, lymphoscintigraphy was performed with a 10-min dynamic study and static planar images at 10 min and 2 h after injection, followed by SPECT/CT. The same scintigraphic procedure was repeated after injection of hybrid ICG-(99m)Tc-nanocolloid the same afternoon in 10 patients or the next morning in 15 patients. The paired images of both injections were evaluated, and count rates in the sentinel nodes were calculated and compared. Sentinel nodes were surgically localized using blue dye, a γ-ray detection probe, a portable γ-camera, and a fluorescence camera.

RESULTS

Lymphatic drainage was visualized in all 25 patients using (99m)Tc-nanocolloid, leading to the identification of 66 sentinel nodes in total. These same sentinel nodes were also identified during the second scintigraphic procedure with ICG-(99m)Tc-nanocolloid. Moreover, a high correlation between the radioactive counting rates in the sentinel nodes of both scintigraphic studies was observed (mean R(2) = 0.83). Intraoperatively (4-23 h after the second injection), all preoperatively identified sentinel nodes could be localized using radio- and fluorescence guidance combined. In total, 95% of the sentinel nodes could be intraoperatively visualized by means of fluorescence imaging, whereas merely 54% stained blue. Ex vivo, all radioactive sentinel nodes were fluorescent and vice versa. No adverse reactions were observed.

CONCLUSION

The lymphatic drainage pattern of ICG-(99m)Tc-nanocolloid is identical to that of (99m)Tc-nanocolloid. This observation, together with the added value of intraoperative fluorescence guidance, warrants wider evaluation of hybrid ICG-(99m)Tc-nanocolloid as a tracer for sentinel node procedures.

Feasibility of sentinel node biopsy in head and neck melanoma using a hybrid radioactive and fluorescent tracer

Purpose

This study was designed to examine the feasibility of combining lymphoscintigraphy and intraoperative sentinel node identification in patients with head and neck melanoma by using a hybrid protein colloid that is both radioactive and fluorescent.

Methods

Eleven patients scheduled for sentinel node biopsy in the head and neck region were studied. Approximately 5 h before surgery, the hybrid nanocolloid labeled with indocyanine green (ICG) and technetium-99m (^99mTc) was injected intradermally in four deposits around the scar of the primary melanoma excision. Subsequent lymphoscintigraphy and single photon emission computed tomography with computed tomography (SPECT/CT) were performed to identify the sentinel nodes preoperatively. In the operating room, patent blue dye was injected in 7 of the 11 patients. Intraoperatively, sentinel nodes were acoustically localized with a gamma ray detection probe and visualized by using patent blue dye and/or fluorescence-based tracing with a dedicated near-infrared light camera. A portable gamma camera was used before and after sentinel node excision to confirm excision of all sentinel nodes.

Results

A total of 27 sentinel nodes were preoperatively identified on the lymphoscintigraphy and SPECT/CT images. All sentinel nodes could be localized intraoperatively. In the seven patients in whom blue dye was used, 43% of the sentinel nodes stained blue, whereas all were fluorescent. The portable gamma camera identified additional sentinel nodes in two patients. Ex vivo, all radioactive lymph nodes were fluorescent and vice versa, indicating the stability of the hybrid tracer.

Conclusions

ICG–^99mTc-nanocolloid allows for preoperative sentinel node visualization and concomitant intraoperative radio- and fluorescence guidance to the same sentinel nodes in head and neck melanoma patients.

Electronic supplementary material

The online version of this article (doi:10.1245/s10434-011-2180-7) contains supplementary material, which is available to authorized users.

Indocyanine green fluorescence-guided sentinel lymph node biopsy in dermato-oncology

BACKGROUND

Sentinel lymph node biopsy (SLNB) for cutaneous malignancies usually carried out with radioactive nanocolloids (Tc-99m). The SLNE is controversially discussed internationally. This is especially given to the high false-negative rate up to 44 %. An alternative could be the fluorescent dye indocyanine green (ICG).

MATERIAL AND METHODS

We investigated the advantage of intraoperative fluorescence detection of lymphatic vessels and SLN with a Near-Infrared (NIR) camera in comparison to conventional methods using preoperative lymphoscintigraphy and SPECT/CT in 22 patients with malignant melanoma.

RESULTS

A total of 61 SLNs were removed in 22 operative procedures. In 7 SLN (10.3 %; 7/68) the histopathological assessment could demonstrate a metasta-tic involvement. 11 additional SLN (19.1 %) in 8 patients were only identified using the fluorescent labeling. Two of these additional SLN (9.1 %; 2/22) showed metastatic involvement.

CONCLUSION

The ICG fluorescence-guided SLNB is an innovative imaging technique for dermato-oncology, reliable and providing additional information in the detection of SLN. Therefore SLNB with fluorescence-dye is an attractive option with intraoperative real-time lymphoscintigraphy to improve the detection of SLN in cutaneous malignancies and potential reduction of the false negative rate in SLN.

Use of sentinel node biopsy for staging parameningeal rhabdomyosarcoma

Identification of nodal involvement is important for treatment planning in patients with rhabdomyosarcoma, and is facilitated by sentinel node biopsy. Although it is employed primarily for extremity tumors, we report using sentinel node biopsy in a patient with parameningeal rhabdomyosarcoma arising in the ethmoid sinus. Lymphoscintigraphy with single photon emission computed tomography following injection of tracer at the tumor site helped identify contralateral cervical node involvement not previously recognized by physical exam, cross sectional imaging, or other functional imaging. This case demonstrates how information from sentinel node identification and biopsy can change therapy recommendations in patients with parameningeal rhabdomyosarcoma.

The additional value of lymphatic mapping with routine SPECT/CT in unselected patients with clinically localized melanoma

PURPOSE

To investigate whether single photon emission computed tomography camera with integrated radiographic computed tomography (SPECT/CT) is of additional value compared to conventional lymphoscintigraphy in routine lymphatic mapping in patients with melanoma.

METHODS

Thirty-five unselected patients with a primary melanoma who were scheduled for wide local excision and sentinel node biopsy underwent conventional lymphoscintigraphy and subsequently SPECT/CT. We determined whether SPECT/CT showed additional sentinel nodes, whether it provided better information on the location of the sentinel nodes, and whether this additional anatomic information led to a change in the planned surgical approach.

RESULTS

SPECT/CT depicted the same 69 sentinel nodes as conventional lymphoscintigraphy in all 35 patients plus found eight additional sentinel nodes in seven patients (20%). In two of these patients (5.7%), an additional nodal basin had to be explored to find the extra sentinel nodes. SPECT/CT provided additional anatomic information that was helpful to the surgeon in 11 patients (31%) and led to an adjustment of the surgical approach in 10 patients (29%).

CONCLUSIONS

SPECT/CT provided relevant additional information in 16 (46%) of the 35 patients. Routine use of SPECT/CT in addition to conventional lymphoscintigraphy is recommended in melanoma patients undergoing lymphatic mapping.

High rate of solitary sentinel node metastases identification by fluorescence-guided lymphatic imaging in breast cancer

BACKGROUND

The lymph node status was shown to be an important prognostic factor for breast cancer, but controversial issues remain. There has been increased focus on optimizing the visualization of lymph nodes for an accurate and selective approach to axillary lymph nodes. Fluorescence-guided lymphatic imaging is a potential candidate for further research on remaining controversies.

METHODS

Forty-seven patients were subject to injection of indocyanine green for navigation to the SLN based on fluorescent dye retention detection. In two groups, patients either received intended axillary lymph node dissection (ALND) and sentinel lymph node biopsy (SLNB) for superstaging or isolated SLNB for minimal-invasive staging. The prospective study was designed to evaluate the technical feasibility with focus on solitary positive SLN.

RESULTS

Visualization of lymphatic vessels with bright fluorescence of the SLN was feasible in 46 of 47 patients. Eighteen of 19 nodal positive patients were correctly identified with a sensitivity of 94.7% in all patients after ALND. After immunohistochemistry, in 19 of 25 overall nodal positive patients (76%) the SLN was the only positive lymph node.

CONCLUSION

Fluorescence-guided imaging using fluorescence retention detection allows transcutaneous navigation with a high rate of solitary positive SLN identification as an alternative technique for further research.

[Evaluation of the sentinel lymph node combining SPECT/CT with the planar image and its importance for the surgical act]

The sentinel node biopsy procedure is based on the hypothesis of the existence of an orderly and predictable pattern of lymphatic drainage to a regional lymph node basin. This results in the consideration of all lymph nodes with direct drainage from the primary tumor as sentinel nodes. The sentinel node is not necessarily the hottest or the most nearby node, although this is often the case. Lymphoscintigraphy has been an essential component for preoperative sentinel node identification. With the new generation of multimodality gamma cameras, SPECT/CT has been incorporated into the sentinel node procedure. The resulting SPECT/CT fused images depict sentinel nodes in an anatomical landscape providing a helpful roadmap for surgeons. Therefore, it is necessary to define the role of SPECT/CT in relation to the classical planar lymphoscintigraphy for the identification of sentinel nodes. To understand the combined use of lymphoscintigraphy and SPECT/CT, the criteria for sentinel node identification on preoperative images must be specified. The authors, based on their experience in this field, present tentative criteria to identify lymph nodes as sentinel nodes both in planar and SPECT/CT images and classify them into different categories. The use of these scintigraphic categories to characterize radioactive lymph nodes is also helpful for surgical decision making.

[The potential role of SPECT/CT in the preoperative detection of sentinel lymph nodes in breast cancer]

Regional lymph node status is the most important prognostic factor in breast cancer. Sentinel lymph node biopsy is the standard method of axillary staging in early breast cancer patients with clinically negative nodes. Preoperative lymphoscintigraphy might support refining biopsy findings by determining the number and location of sentinel lymph nodes. In aged or overweight patients, in the presence of atypical or extra-axillary lymphatic drainage, non-visualized lymph nodes, or sentinel lymph nodes close to the isotope injection site, detection could be aided by a new, hybrid imaging tool: the single-photon emission computed tomography combined with computed tomography (3D SPECT/CT). For the first time in Hungarian language, authors overview the literature: all 14 English-language articles on the implementation of 3D SPECT/CT in sentinel lymph node detection in breast cancer are included. It is concluded that 3D SPECT/CT increases the success rate and quality of preoperative sentinel node identification, and is capable of providing a more accurate staging of breast cancer patients in routine clinical practice.

Added value of intraoperative real-time imaging in searches for difficult-to-locate sentinel nodes

Localization of sentinel lymph nodes can be challenging if they are in difficult anatomic locations or near high radiotracer activity. The purpose of this study was to assess the value of intraoperative real-time imaging using a portable gamma-camera in conjunction with a conventional gamma-counting probe when it is difficult to localize the sentinel node.

METHODS

After (99m)Tc-nanocolloid injection, patients with various malignancies underwent presurgical lymphoscintigraphy followed by surgery (usually the next day). We evaluated 20 patients who required sentinel lymph node biopsy and in whom the location or other characteristics of the sentinel node would make intraoperative retrieval difficult. During surgery, the sentinel node was localized using a portable gamma-camera together with a hand-held gamma-probe. A (153)Gd pointer or (125)I seed was used to better depict the sentinel node location in real time.

RESULTS

Using only a conventional hand-held gamma-probe, surgeons were able to definitively localize the sentinel node in 15 of 20 patients. Intraoperatively, the portable gamma-camera showed uptake by the definite sentinel node in 19 of 20 patients and helped to precisely localize the node with the hand-held gamma-probe in 4 patients. In 1 of these patients, the sentinel node was metastatic.

CONCLUSION

The combination of a standard hand-held gamma-probe and real-time imaging provided by a portable gamma-camera offers a high intraoperative detection rate in patients with difficult sentinel node localization as assessed by presurgical lymphoscintigraphy.