Dynamic MR lymphangiography and carbon dye for sentinel lymph node detection: A solution for sentinel lymph node biopsy in mucosal head and neck cancer

New Developments in Imaging for Sentinel Lymph Node Biopsy in Early-Stage Oral Cavity Squamous Cell Carcinoma

Sentinel lymph node biopsy (SLNB) is a diagnostic staging procedure that aims to identify the first draining lymph node(s) from the primary tumor, the sentinel lymph nodes (SLN), as their histopathological status reflects the histopathological status of the rest of the nodal basin. The routine SLNB procedure consists of peritumoral injections with a technetium-99m [^99mTc]-labelled radiotracer followed by lymphoscintigraphy and SPECT-CT imaging. Based on these imaging results, the identified SLNs are marked for surgical extirpation and are subjected to histopathological assessment. The routine SLNB procedure has proven to reliably stage the clinically negative neck in early-stage oral squamous cell carcinoma (OSCC). However, an infamous limitation arises in situations where SLNs are located in close vicinity of the tracer injection site. In these cases, the hotspot of the injection site can hide adjacent SLNs and hamper the discrimination between tracer injection site and SLNs (shine-through phenomenon). Therefore, technical developments are needed to bring the diagnostic accuracy of SLNB for early-stage OSCC to a higher level. This review evaluates novel SLNB imaging techniques for early-stage OSCC: MR lymphography, CT lymphography, PET lymphoscintigraphy and contrast-enhanced lymphosonography. Furthermore, their reported diagnostic accuracy is described and their relative merits, disadvantages and potential applications are outlined.

Magnetic detection of sentinel nodes in oral squamous cell carcinoma by means of superparamagnetic iron oxide contrast

The aim was to evaluate sentinel node detection capacity by means of a magnetic probe in 11 patients with oral squamous cell carcinoma at stages T1-T2 received submucosal injections of a superparamagnetic iron oxide contrast agent (SPIO). A magnetic probe was used for sentinel node biopsy. The use of SPIO and magnetic probes in the early stages of oral cancer may offer an alternative to conventional radioisotope techniques and/or elective neck dissection.

MR lymphography for sentinel lymph node detection in patients with oral cavity cancer: Preliminary clinical study

BACKGROUND

The purpose of this study was to evaluate the feasibility of MR lymphography with interstitial injection of a gadolinium-based contrast agent for identifying sentinel lymph nodes in patients with oral cavity cancer and clinically negative neck.

METHODS

Pretreatment MR lymphography with a differential subsampling with cartesian ordering (DISCO) sequence was performed in 26 patients with resectable oral cavity cancer and clinically negative neck, after peritumoral injection of 1-mL diluted gadobutrol. The accuracy of sentinel lymph node identification by MR lymphography was assessed and compared with the final histopathological results.

RESULTS

The MR lymphography consistently visualized the 44 sentinel lymph nodes in all 26 patients. In all but 1 patient with pathologically positive neck, assumed sentinel lymph nodes revealed metastatic involvement.

CONCLUSION

Pretreatment MR lymphography is a safe and feasible imaging technique that can help clinicians identify sentinel lymph nodes with a high risk of occult metastases in patients with oral cavity cancer, enabling focused preoperative biopsy in these high-risk patients.

Feasibility of sentinel lymph node dissection using Tc-99m phytate in papillary thyroid carcinoma

Purpose

Various methods of sentinel lymph node (SLN) biopsy in thyroid cancer have been introduced. Tc-99m phytate as a radiotracer has been successfully utilized for SLN biopsy in breast, cervix, and endometrial cancer. We assessed the feasibility of SLN dissection using Tc-99m phytate in papillary thyroid carcinoma (PTC).

Methods

Seventeen patients with PTC were prospectively enrolled. Ultrasound-guided peritumoral injection of 55.5 MBq Tc-99m phytate in 0.25-mL normal saline was performed. Preoperative single-photon emission-computed tomography (SPECT) and intraoperative gamma-probe were used for SLN detection during operation.

Results

Identification rate of SLNs was 70.6% (12 of 17) with SPECT, and 88.2% (15 of 17) with gamma-probe. Combined SPECT and gamma-probe had identification rates of 88.2% (15 of 17). Identification rates of SLNs in central LN compartments were 82.4% (14 of 17) and 41.2% (7 of 17) in lateral LN compartments. Overall sensitivity, specificity, positive predictive value, and negative predictive value of the results of SLN biopsy were 91.6%, 100%, 88.4%, and 100%, respectively. Eight patients (47.1%) had metastasis in SLNs; all patients had SLN metastasis in the central compartment and 2 patients had SLN metastasis in both the central and lateral compartments.

Conclusion

Combined SPECT and gamma-probe could detect SLNs with an 88.2% identification rate in PTC. SLN biopsy using Tc-99m phytate is technically feasible. Further investigation is warranted for clinical application of Tc-99m phytate in PTC.

Feasibility of Endoscopic Sentinel Node Biopsy in the Porcine Neck

OBJECTIVE: To assess the feasibility of endoscopic sentinel node biopsy (SNB) using a tracer dye in a pig model.

STUDY DESIGN AND SETTING: This was a prospective, nonrandomized experimental study in Yorkshire pigs. The posterolateral tongues of three animals were injected with a one-to-one solution of carbon dye to methylene blue dye. Endoscopic SNB was performed and stained lymph nodes identified and retrieved, followed by an open dissection to recover any remaining nodes. Specimens were analyzed by a pathologist for staining, size, and structural integrity.

RESULTS: Six unilateral endoscopic SNBs were performed without complications. During endoscopic dissection, gross blue-staining of a sentinel node was noted in four of six dissections (66%). One of six sentinel nodes demonstrated histologic evidence of carbon staining. Structural integrity of all nodes was intact upon histological evaluation.

CONCLUSION/SIGNIFICANCE: Endoscopic cervical SNB in pigs is feasible but has limitations based on lymph node size and reliability of tracer dyes. Further study is warranted to perfect tracer dyes and retrieval methods to improve this technique.

Sentinel lymph node biopsy using computed tomographic lymphography in patients with early tongue cancer

Conclusions: Because computed tomography (CT) lymphography provides preoperative images of anatomic relationships between a tumor, its associated lymph vessels, and the sentinel lymph node (SLN), it may aid in directing the SLN biopsy for management of early tongue cancer. Objectives: SLN biopsy using a radioisotope (RI) generally has been performed in head and neck cancer. However, this method can be performed only at institutions that are licenced for its use. In this study, we evaluated the utility of performing SLN biopsy in patients with early tongue cancer using the newly developed technique of CT lymphography. Methods: Enrolled in this study were 31 patients with T1N0 or T2N0 tongue cancer. CT images were obtained before and after injection of iopamidol into the peritumoral region and the SLN was identified as the first enhanced lymph node. SLN biopsy was performed using CT lymphographic guidance combined with blue dye injection. Results: The SLN was detected by CT lymphography in 28 cases (90.3%). By intraoperative frozen section examination, metastases to SLNs were found in 4 (14.3%) (T1N0, 1 patient; T2N0, 3 patients) of the 28 patients. Of these four, SLN micrometastases were found in one patient.

A simple novel prognostic model for early stage oral tongue cancer

The prognostication of patient outcome is one of the greatest challenges in the management of early stage oral tongue squamous cell carcinoma (OTSCC). This study introduces a simple histopathological model for the prognostication of survival in patients with early OTSCC. A total of 311 cases (from Finland and Brazil) with clinically evaluated early stage OTSCC (cT1-T2cN0cM0) were included in this multicentre retrospective study. Tumour budding (B) and depth of invasion (D) were scored on haematoxylin-eosin-stained cancer slides. The cut-off point for tumour budding was set at 5 buds (low <5; high ≥5) and for depth of invasion at 4mm (low <4mm; high ≥4mm). The scores of B and D were combined into one model: the BD predictive model. On multivariate analysis, a high risk score (BD score 2) correlated significantly with loco-regional recurrence (P=0.033) and death due to OTSCC (P<0.001) in early stage OTSCC. The new BD model is a promising prognostic tool to identify those patients with aggressive cases of early stage OTSCC who might benefit from multimodality treatment.

Prognostic factors in advanced pharyngeal and oral cavity cancer; significance of multimodality imaging in terms of 7th edition of TNM

As with most cancers the prognosis in pharyngeal and oral cavity cancer largely depends on tumour stage. Physical examination, including endoscopy should be combined with technical radiologic imaging to record the precise extent of tumour. The TNM staging system of the head and neck region is, in fact, an anatomic staging system that describes the anatomic extent of the primary tumour as well as the involvement of regional lymph nodes and distant metastases. Modifications in the TNM staging system should consider not only the expert opinions and published reports in the literature but the technical advances in technology for improved assessment of tumour extent and the shifting paradigms in therapeutic strategies. “T” stage of the tumour is defined by its size, the depth of the invasion and the involvement of vital structures. In the 7th edition of TNM classification, for stage T4 tumors (larger than 4 cm), subcategories a and b were introduced to indicate the involvement of vital structures and their suitability for surgical resection (except for nasopharynx cancer). Nodal metastasis is the most important predictor of outcome for squamous cell cancer of the head and neck.

Better and more reliable methods of pretreatment tumour assessment are therefore crucial to ensure that the clinical assessment of tumor approximates its actual pathologic extent.

CT and MRI are both useful for assessing extensions of pharyngeal- and oral cavity cancer in advanced stage. MRI is superior in visualizing most primary tumour sites.

Sentinel lymph node biopsy is unsuitable for routine practice in younger female patients with unilateral low-risk papillary thyroid carcinoma

Background

Sentinel lymph node (SLN) biopsy has been used to assess patients with papillary thyroid carcinoma (PTC). To achieve its full potential the rate of SLN identification must be as close to 100 percent as possible. In the present study we compared the combination of preoperative lymphoscintigraphy scanning by sulfur colloid labeled with 99 m Technetium, gamma-probe guided surgery, and methylene blue with methylene blue, alone, for sentinel node identification in younger women with unilateral low-risk PTC.

Methods

From January 2004 to January 2007, 90 female patients, ages 23 to 44 (mean = 35), with unilateral low-risk PTC (T_1-2N₀M₀) were prospectively studied. Mean tumor size was 1.3 cm (range, 0.8-3.7 cm). All patients underwent unilateral modified neck dissection. Prior to surgery, patients had, by random assignment, identification and biopsy of SLNs by methylene blue, alone (Group 1), or by sulfur colloid labeled with 99 m Technetium, gamma-probe guided surgery and methylene blue (Group 2).

Results

In the methylene blue group, SLNs were identified in 39 of 45 patients (86.7%). Of the 39 patients, 28 (71.8%) had positive cervical lymph nodes (pN+), and 21 patients (53.8%) had pSLN+. In 7 of the 28 pN+ patients (25%), metastases were also detected in non-SLN, thus giving a false-negative rate (FNR of 38.9% (7/18), a negative predictive value (NPV) of 61.1% (11/18), and an accuracy of 82.1% (32/39). In the combined technique group, the identification rate (IR) of SLN was 100% (45/45). Of the 45 patients, 27 (60.0%) had pN+, 24 (53.3%) had pSLN+. There was a FNR of 14.3% (3/21), a NPV of 85.7% (18/21), and an accuracy of 93.3% (42/45). The combined techniques group was significantly superior to the methylene blue group in IR (p = 0.035). There were no significant differences between two groups in sensitivity, specificity, NPV, or accuracy. Location of pN+ (55 patients) in 84 patients was: level I and V, no patients; level II, 1 patient (1.2%); level III, 6 patients (7.2%); level III and IV, 8 patients (9.5%); level IV, alone, 8 patients (9.5%); level VI, 32 patients (38.1%). In all 90 patients, IR of SLN was 93.3%, FNR, 25.6%, NPV, 74.4%, and accuracy rate, 88.1 percent.

Conclusions

Compared to a single technique, there was a significantly higher SLN identification rate for the combined technique in younger female with ipsilateral, low-risk PTC (T_1-2N₀M₀). Thus, a combined SLN biopsy technique seems to more accurately stage lymph nodes, with better identification of SLN located out of the central compartment. Regardless of the procedure used, the high FNR renders the current SLN techniques unsuitable for routine practice. Based on these results, prophylactic node dissection of level VI might be considered because 38.1% of our patients had such node metastases.

Site-specific lymphatic mapping relative to lingual septum in localizing the regional lymph nodes of tongue - an animal study

BACKGROUND AND OBJECTIVES

With technical adaptations, recent studies showed SLNB could predict cervical nodes status of head and neck carcinoma with high accuracy. However, as for tongue carcinoma, such technical adaptations seem to be not enough because the tongue has peculiar characteristic which may demand a specific procedure for accurate lymphatic mapping. This investigation explored the effect of lingual septum on lymphatic mapping of tongue to provide data for achieving an accurate lymphatic mapping for managing early tongue carcinoma.

METHODS

Four doses of Methylene Blue were injected into various parts of 64 rabbits' tongue, then diffusion range of Methylene Blue in tongue and sites of cervical nodes stained blue were noted. Finally, the tongues were resected for further histological examination and morphometric assessments.

RESULTS

There was lingual septum in the tongue and the diffusing of Methylene Blue could be terminated by lingual septum. Blue-stained nodes were identified in 84 lateral necks of 60 rabbits.

CONCLUSIONS

A site-specific way of lymphatic mapping relative to lingual septum should be developed for staging early tongue carcinoma.

Lymphosonographic sentinel node biopsy of the supraglottis in a swine model

OBJECTIVE

To test the feasibility of a novel contrast-enhanced ultrasound (CEUS) technique, or lymphosonography, for sentinel node biopsy (SNB) of the supraglottis in a porcine model.

STUDY DESIGN AND SETTING

In this prospective, nonrandomized animal study, blue dye and ultrasound contrast agent were injected into the supraglottis in seven 50-kg Yorkshire swine. Transcutaneous CEUS was used to identify real-time lymphatic flow of contrast through lymph channels (LC) to the sentinel lymph node (SLN). SNB was carried out, visually identifying a blue node, with the assistance of intraoperative CEUS. Bilateral modified radical neck dissections were performed to search for any residual contrast-positive or blue SLNs.

RESULTS

In each case, at least one SLN was identified by preoperative CEUS. A total of 12 nodes were identified on preoperative CEUS, and 11 of 12 nodes were stained with blue dye (91.7%). No residual blue or contrast-positive nodes were identified on neck dissection.

CONCLUSIONS

Lymphosonographic SNB of the supraglottis in a porcine model is technically feasible, and yields results comparable to traditional blue dye-guided techniques. No "shine-through" effect or nonsequential nodal enhancement occurred. This technique holds promise for sentinel node biopsy and allows a novel method for in vivo investigation of the lymphatic system.

Sentinel lymph node biopsy using dynamic lymphoscintigraphy combined with ultrasound-guided fine needle aspiration in penile carcinoma

The purpose of this study was to assess the utility of sentinel lymph node lymphoscintigraphy (SLNL) and ultrasound-guided fine needle aspiration cytology (FNAC) in patients with penile carcinoma. A prospective study was undertaken of 64 patients with stage T1 (or greater) clinically N0 squamous cell carcinoma of the penis. Patients underwent SLNL and bilateral groin ultrasonography with or without FNAC. Following intradermal blue dye, patients underwent unilateral or bilateral sentinel lymph node excision biopsy (SNB). 17 patients had sentinel nodes that contained metastases (21 nodal basins). Lymphatic drainage was demonstrated in all patients by lymphoscintigraphy. Bilateral drainage was seen in 57/64 patients. 61/64 patients had ultrasonography of the inguinal basins on the same day as FNAC of 38 basins. FNAC showed malignancy in eight basins. FNAC was negative in six basins, which were subsequently shown to be positive following SNB. 82 inguinal basins did not warrant FNAC by ultrasound criteria, of which 5 contained metastases at SNB. The sensitivity and specificity of ultrasonography was 74% and 77%, respectively. The positive and negative predictive values were 37% and 94%, respectively. Two patients had a negative initial SNB; however, ultrasonography identified a metastatic node and re-evaluation of the sentinel node confirmed micro-metastases. There has been no evidence of recurrence in any patients with negative SNB (during 6-28 months' follow-up). In conclusion, when investigating clinically stage N0 penile cancer, the combination of SNB and groin ultrasonography, with or without FNAC, identifies accurately those with occult nodal metastases. Ultrasonography alone is not adequate as a staging technique, and SNB alone might miss between 5% and 10% of metastases.

Advances in imaging head and neck tumours

PURPOSE OF REVIEW

The intention of this article is to review the recently published studies summarizing new developments in medical imaging for head and neck tumours.

RECENT FINDINGS

Recent technological improvements in imaging have modified the diagnostic approach to these tumours. The main trends can be summarized as follows: improvement in resolution owing to the detection and study of smaller lesions (achieved with magnetic resonance surface coils and parallel imaging); acceleration of data acquisition thus achieving high-quality vascular imaging; improvement in data manipulation and fusion techniques with metabolic imaging from positron emission tomography scanners, permitting more accurate delineation of target volumes for new radiation therapy techniques. In addition, new techniques are emerging leading to a switch from purely anatomical imaging to more functional or metabolic techniques, including dynamic contrast-enhanced approaches to studying tumour perfusion and vascularization, magnetic resonance spectroscopic techniques to assess tissue metabolites, and magnetic resonance diffusion techniques to evaluate free water motion and interstitial space.

SUMMARY

Finally, new contrast agents have been developed to detect and characterize metastatic lymph nodes, even when they do not match the classical size criteria.

Lymph node staging

Cancers of the head and neck (HNC) include cancers of the larynx, nasal passages/nose, oral cavity, pharynx, salivary glands, buccal regions, and thyroid. In these cancers, lymph node staging and localization of pathological lymph nodes are necessary to decide on either (neo) adjuvant or surgical therapy and are a major factor for the prognosis in HNC patients. Cervical node metastases have different incidence, and their presence is associated with a decrease in global survival to roughly half and with higher recurrence rates. The node metastases can be categorized in the following 2 groups: overt (clinical) or nonovert (occult). The latter can be subcategorized as metastases detectable by traditional methods (eg, staining) or "submicroscopic" metastases, only evident with immunohistochemical or molecular analysis. Compared with clinical invasive and laboratory examinations, which may have complications and are expensive, radiology plays an important role in lymph node staging. Mainly, the overt node metastases are the field of radiological imaging, and second, the detection of nonovert metastases is important and holds promise for the future because many patients of those initially classified as cN0 have, in fact, occult metastatic disease (pN1). Vice versa, radiological imaging has to avoid false-positive results that can lead to an elective or radical neck dissection, which are associated with increased morbidity and mortality and thus overshadow the improvement in survival. Radiological imaging plays a role not only as an initial staging of N+ but also in the case of N0 due to the continuing controversy for the treatment of N0 patients. A close observation of the patient may reveal a positive node in the follow-up. The imaging modalities used for the node staging in HNC patients include ultrasound, contrast-enhanced computed tomography, contrast-enhanced magnetic resonance imaging (MRI), and positron emission tomography scans. None of the above-mentioned methods reaches a 100% sensitivity or specificity, and the accuracy of the exact number of metastases or levels involved has not been studied; thus, neck dissection with subsequent pathological examination remains the gold standard for node staging. Among the described cross-sectional imaging modalities, MRI presents a lot of advantages mainly due to the increased soft tissue contrast and the ability to obtain tissue characteristics in different sequences, including diffusion- and perfusion-weighted sequences and proton spectroscopy imaging. The lack of the radiation burden makes MRI suitable for a close follow-up of the patient, and the imaging with the use of new intravenous contrast material (such as ultrasmall iron oxide particles) seems superior to the conventional. In this article, we will focus on the lymph node MRI staging in HNC patients and the MR anatomy of the nodes, the necessary diagnostic workup, and the advantages of the method over computed tomography. The possibilities of the new imaging sequences and the treatment implications will be addressed as well.

Current status of sentinel lymph node navigation surgery in breast and gastrointestinal tract

Sentinel lymph node biopsy (SLNB) has been developed as a new diagnostic and therapeutic modality in melanoma and breast cancer surgery. The purpose of the SLNB include preventing the operative morbidity and improving the pathologic stage by focusing on fewer lymph nodes using immunocytochemic and molecular technology has almost achieved in breast cancer surgery. The prognostic meaning of immunocytochemically detected micrometastases is also evaluating in the SLN and bone marrow aspirates of women with early-stage breast cancer. SLNB using available techniques have suggested that the lymphatic drainage of the gastrointestinal tract is much more complicated than other sites, skip metastasis being rather frequent because of an aberrant lymphatic drainage outside of the basin exist. At the moment, the available data does not justify reduced extent of lymphadenectomy, but provides strong evidence for an improvement in tumor staging on the basis of SLNB. Two large scale prospective multi-center trials concerning feasibility of gamma-probe and dye detection for gastric cancer are ongoing in Japan. Recent studies have shown favorable results for identification of SLN in esophageal cancer. CT lymphography with endoscopic mucosal injection of iopamidol was applicable for SLN navigation of superficial esophageal cancer. The aim of surgical treatment is complete resection of the tumor-infiltrated organ including the regional lymph nodes. Accurate detection of SLN can achieve a selection of a more sophisticated tailor made approach. The patient can make a individualized choice from a broader spectrum of therapeutic options including endoscopic, laparoscopic or laparoscopy-assisted surgery, modified radical surgery, and typical radical surgery with lymph node dissection. Ultrastaging by detecting micrometastasis at the molecular level and the choice of an adequate treatment improve the postoperative quality of life and survival. However these issues require further investigation.

Endoscopic Sentinel Lymph Node Biopsy in a Porcine Model

OBJECTIVE

The objective of this study was to investigate the feasibility of endoscopic sentinel lymph node biopsy in a porcine model.

METHODS

One hundred microcuries of technetium-labeled sulfa colloid (Tc-SC) was injected into the right and left ventrolateral surfaces of the oral tongue of six adult Yorkshire pigs. A handheld gamma probe was used to locate the region of focal radioactivity on the neck that corresponded to the sentinel lymph node (SLN). Next, 0.25 mL of isosulfan blue dye was injected into the Tc-SC injection sites on the tongue. Endoscopic SLN dissection was then performed using a combination of balloon dissection and CO2 insufflation. The operative time, blood loss, and radioactivity of the SLN were measured for each animal.

RESULTS

The SLN was detected transcutaneously with the gamma probe, and endoscopic SLN excision was successful. Endoscopic visualization and an endoscopic gamma probe confirmed the presence of both isosulfan blue dye and radiopositivity in the SLN in each pig. The procedure lasted 22 to 61 minutes (median duration, 35 minutes). There was no measurable blood loss in any of the animals. Mean radioactivity measured 14,466 counts/second per lymph node.

CONCLUSIONS

Endoscopic SLN biopsy for oral tongue lesions is feasible and warrants further study.

Sentinel node biopsy and head and neck tumors—Where do we stand today?

BACKGROUND

Sentinel lymph node sampling may be studied profitably in series of patients with 1 tumor type, such as breast carcinoma, in 1 anatomic locale. The present work analyzes the efficacy of sentinel node sampling in a pathologically diverse group of lesions from an anatomically diverse region such as the head and neck; however, there are risks conflating the findings in different tumors with radically different behaviors, in the process producing muddled data. This report reviews the head and neck experience with sentinel sampling and concludes that certain tumor types that have a known propensity for aggressive behavior are the best candidates for trials employing sentinel node sampling; candidates include many cutaneous melanomas of the head and neck, oropharyngeal squamous carcinomas, and selected thyroid carcinomas. Despite the growing popularity of sentinel node sampling in a variety of regions of the body, however, at this juncture this technique remains an investigational procedure, pending demonstration of a tangible improvement in patient outcome through its use. It is recommended that studies of the efficacy of this technique strive, whenever possible, to segregate results of different tumor types in different head and neck locales from one another so as to produce more focused findings for discrete types of malignancies, and not group together tumor types that may in reality exhibit different biological behaviors.

Sentinel Node Localization in Head and Neck Tumors

Sentinel lymph node biopsy (SLNB) is a minimally invasive method that was developed to stage the regional lymphatics of patients with cutaneous melanoma. Many studies performed worldwide have shown that SLNB is a feasible method to stage the cervical lymphatics in patients with head and neck squamous cell carcinoma (HNSCC). The accuracy of SLNB in patients with HNSCC is currently under investigation in a multicenter study sponsored by the American College of Surgeons Oncology Group that compares the results of SLNB with standard elective neck dissection. Research to date has also shown that multiple SLNs and individualized drainage patterns characterize head and neck mucosal sites. These findings suggest that lymphoscintigraphy alone may be useful to delineate the lymphatic basins that require treatment in patients with HNSCC and in patients whose head and neck lymphatics are disrupted because of prior surgery or irradiation.