The role of SPECT-CT in the lymphoscintigraphic identification of sentinel nodes in patients with oral cancer

Sentinel node-assisted neck dissection in advanced oral squamous cell carcinoma-A new protocol for staging and treatment

BACKGROUND

Sentinel lymph node biopsy (SLNB) is used to improve the staging of and guide treatment in patients with early-stage T1-T2 N0 oral squamous cell carcinoma (OSCC). The role of sentinel nodes (SNs) and the use of SN-technique in advanced OSCC (T3-T4 and/or N+) remain to be evaluated. This study investigates the nodal drainage and the rate of positive SNs (SNs+) in all stages of OSCC.

MATERIALS AND METHODS

In total, 85 patients with T1-T4 OSCC diagnosed 2019-2021 were included. We used a prolonged interval between peritumoral injection of radionuclide and SPECT-CT to include all SNs.

RESULTS

Patients with advanced OSCC presented a higher proportion of contralateral lymphatic drainage and a higher rate of SN+ compared to patients with early-stage disease. T3-T4 and N+ tumors presented a tendency for a higher rate of contralateral lymphatic drainage compared to T1-T2 and N0 tumors (p = 0.1). The prevalence of positive nodes (SNs+) was higher among patients with advanced disease, T3-T4 versus T1-T2 (p = 0.0398).

CONCLUSION

SN-assisted ND enables identification and removal of all SNs + and has the potential for more accurate staging and could possibly give prognostic advantages regarding regional recurrence for all OSCC patients, especially among those with advanced disease. The precise localization of the SNs + also suggests that a more individualized ND approach might be possible in the future even for patients with advanced OSCC.

A Systematic Review of Oral Biopsies, Sample Types, and Detection Techniques Applied in Relation to Oral Cancer Detection

Background: Early identification of the stage of oral cancer development can lead to better treatment outcomes and avoid malignant transformation. Therefore, this review aims to provide a comprehensive overview that describes the development of standardized procedures for oral sample collection, characterization, and molecular risk assessment. This can help investigators to choose the appropriate sampling method and downstream analyses for different purposes. Methods: This systematic review was conducted according to the PRISMA guidelines. Using both PubMed and Web of Science databases, four independent authors conducted a literature search between 15 and 21 June 2021. We used key search terms to broaden the search for studies. Non-conforming articles were removed using an EndNote-based and manual approach. Reviewers used a designed form to extract data. Results: This review included a total of 3574 records, after eliminating duplicate articles and excluding papers that did not meet the inclusion criteria. Finally, 202 articles were included in this review. We summarized the sampling methods, biopsy samples, and downstream analysis. The biopsy techniques were classified into tissue and liquid biopsy. The common sequential analysis of tissue biopsy includes histopathological examination such as H&E or IHC to identify various pathogenic features. Meanwhile, liquid samples such as saliva, blood, and urine are analyzed for the purpose of screening to detect mutations in cancer. Commonly used technologies are PCR, RT-PCR, high-throughput sequencing, and metabolomic analysis. Conclusions: Currently, tissue biopsies provide increased diagnostic value compared to liquid biopsy. However, the minimal invasiveness and convenience of liquid biopsy make it a suitable method for mass screening and eventual clinical adoption. The analysis of samples includes histological and molecular analysis. Metabolite analysis is rising but remains scarce.

Usefulness of Sentinel Lymph Node Biopsy for Oral Cancer: A Systematic Review and Meta-Analysis

OBJECTIVE

We assessed the diagnostic accuracy of sentinel lymph node biopsy (SLNB) for detecting neck nodal metastasis in early oral squamous cell carcinoma (OSCC) as an alternative to elective neck dissection.

STUDY DESIGN

A systematic search for relevant literature was conducted in the PubMed, SCOPUS, Embase, Web of Science, and Cochrane databases.

METHODS

Two reviewers individually searched the five databases up to November 2019. For studies that met inclusion criteria, data on patient diagnoses were pooled, including true positives, true negatives, false positives, and false negatives. Methodological quality was checked with the Quality Assessment of Diagnostic Accuracy Studies (version 2) tool.

RESULTS

In total, 98 observational or retrospective studies were included. The diagnostic odds ratio of SLNB was 326.165 (95% confidence interval [CI]: 231.477-459.587; I²  = 0%). The area under the summary receiver operating characteristic curve was 0.982. Sensitivity was 0.827 (95% CI: 0.804-0.848), and specificity was 0.981 (95% CI: 0.975-0.986). The correlation between sensitivity and the false positive rate was -0.076, which indicates that heterogeneity did not exist. Subgroup analyses were performed with the subgroups reference test type, publication year, and study type. No significant difference was found within the reference test type subgroup. However, differences within the publication year and study type subgroups were significant, where the retrospective study subgroup was significantly more sensitive and specific than the prospective study subgroup.

CONCLUSION

Results of this meta-analysis imply that the high specificity of SLNB supports its role as a diagnostic tool for patients with clinical tumor stage (CT)1-2 clinically negative (N0) OSCC. More studies should be done to further verify the results of this study.

LEVEL OF EVIDENCE

2a Laryngoscope, 131:E459-E465, 2021.

SPECT-CT and intraoperative portable gamma-camera detection protocol for sentinel lymph node biopsy in oral cavity squamous cell carcinoma

OBJECTIVE

The aim of this study was to evaluate a multimodality approach to sentinel lymph node biopsy (SLNB) detection with lymphoscintigraphy and single-photon emission computed tomography (SPECT)/computed tomography (CT). When combined with intraoperative imaging by a portable gamma camera (PGC), improved SLNB accuracy and detection rate may result.

MATERIAL AND METHODS

A total of 42 patients selected for SLNB in node-negative T1 and T2 oral squamous cell carcinoma were retrospectively analyzed. The detection protocol consisted of preoperative lymphoscintigraphy and SPECT/CT performed the day before surgery. Intraoperative sentinel lymph node (SLN) detection was done with the aid of a PGC in association with hand-held gamma probe.

RESULTS

All SLN detected in the preoperative study could be harvested except for one case. A total of 131 SLN were resected. This number was higher than the SLN depicted on lymphoscintigraphy (119 SLNs) and SPECT/CT (123 SLNs). Sublingual SLNs were observed in two cases (4.76%). These SLNs were detected by SPECT/CT but not by lymphoscintigraphy. Five (3.8%) additional SLNs not previously visualized on lymphoscintigraphy or on SPECT/CT were detected intraoperatively with the aid of the PGC. Positive SLNs were detected in eight cases (19%). Micrometastases were detected in five cases (62%) and macrometastases in three cases (38%).

CONCLUSION

The SLNB detection protocol described contributes to more accurate study and detection.

Comparison of SPECT/CT and Planar Lympho-scintigraphy in Sentinel Node Biopsies of Oral Cavity Squamous Cell Carcinomas

Introduction:

Evidence supporting the use of Sentinel node biopsy (SNB) for nodal staging of early oral squamous cell carcinomas (OSCC) appears to be very promising. Pre-operative lymphatic mapping using planar lymphoscinitigraphy (PL) with or without SPECT/CT in the SNB procedure is useful in sentinel node localization and for planning appropriate surgery. Recently, a large prospective multi-centric study evaluating SNB in cutaneous melanoma, breast and pelvic malignancies, demonstrated that adding SPECT to PL leads to surgical adjustments in a considerable number of patients. Our aim of this study was to evaluate the incremental value of additional SPECT/CT over PL alone in SNB for OSCC.

Materials and Methods:

This was a retrospective analysis of 44 patients (40- tongue, 4- buccal mucosa) with T1-T2, clinically N0 oral cavity SCC who underwent sentinel node biopsy procedure. PL and SPECT lymphoscinitigraphy images were compared for pre-operative mapping of sentinel nodes.

Results:

Using a handheld gamma probe, a total of 179 sentinel nodes were harvested, with a mean of 4.06 per patient. PL revealed 75 hotspots with a mean of 1.70 per patient, and SPECT/CT revealed 92 hotspots with a mean of 2.09 per patient. Additional hotpots were identified in 14 patients on SPECT/CT, which included 4 patients, where PL did not detect any sentinel nodes.

Conclusion:

Pre-operative SPECT/CT in addition to planar lympho-scinitigraphy in sentinel node biopsies of oral cavity SCC detects more number of sentinel nodes compared to planar imaging alone. The higher sensitivity of SPECT combined with better anatomical localization using diagnostic CT may further improve the precision of SNB procedure.

The added value of SPECT-CT for the identification of sentinel lymph nodes in early stage oral cancer

PURPOSE

To assess the role of single-photon emission computed tomography with computed tomography (SPECT-CT) for the identification of sentinel lymph nodes (SLNs) in patients with early stage (T1-T2) oral cancer and a clinically negative neck (cN0).

METHODS

In addition to planar lymphoscintigraphy, SPECT-CT was performed in 66 consecutive patients with early stage oral cancer and a clinically negative neck. The addition of SPECT-CT to planar images was retrospectively analyzed for the number of additional SLNs, more precise localization of SLNs, and importance of anatomical information by a team consisting of a nuclear physician, surgeon, and investigator.

RESULTS

Identification rate for both imaging modalities combined was 98% (65/66). SPECT-CT identified 15 additional SLNs in 14 patients (22%). In 2/15 (13%) of these additional SLNs, the only metastasis was found, resulting in an upstaging rate of 3% (2/65). In 20% of the patients with at least one positive SLN, the only positive SLN was detected due to the addition of SPECT-CT. SPECT-CT was considered to add important anatomical information in two patients (3%). In 5/65 (8%) of the patients initially scored SLNs on planar lymphoscintigrams were scored as non-SLNs when SPECT-CT was added. There were four false-negative SLN biopsy procedures in this cohort.

CONCLUSIONS

The addition of SPECT-CT to planar lymphoscintigraphy is recommended for the identification of more (positive) SLNs and better topographical orientation for surgery in sentinel lymph node biopsy for early stage oral cancer.

Sentinel Node in Oral Cancer: The Nuclear Medicine Aspects. A Survey from the Sentinel European Node Trial

PURPOSE

Nuclear imaging plays a crucial role in lymphatic mapping of oral cancer. This evaluation represents a subanalysis of the original multicenter SENT trial data set, involving 434 patients with T1-T2, N0, and M0 oral squamous cell carcinoma. The impact of acquisition techniques, tracer injection timing relative to surgery, and causes of false-negative rate were assessed.

METHODS

Three to 24 hours before surgery, all patients received a dose of Tc-nanocolloid (10-175 MBq), followed by lymphoscintigraphy. According to institutional protocols, all patients underwent preoperative dynamic/static scan and/or SPECT/CT.

RESULTS

Lymphoscintigraphy identified 723 lymphatic basins. 1398 sentinel lymph nodes (SNs) were biopsied (3.2 SN per patient; range, 1-10). Dynamic scan allowed the differentiation of sentinel nodes from second tier lymph nodes. SPECT/CT allowed more accurate anatomical localization and estimated SN depth more efficiently. After pathological examination, 9.9% of the SN excised (138 of 1398 SNs) showed metastases. The first neck level (NL) containing SN+ was NL I in 28.6%, NL IIa in 44.8%, NL IIb in 2.8%, NL III in 17.1%, and NL IV in 6.7% of positive patients. Approximately 96% of positive SNs were localized in the first and second lymphatic basin visualized using lymphoscintigraphy. After neck dissection, the SN+ was the only lymph node containing metastasis in approximately 80% of patients.

CONCLUSIONS

Best results were observed using a dynamic scan in combination with SPECT/CT. A shorter interval between tracer injection, imaging, and surgery resulted in a lower false-negative rate. At least 2 NLs have to be harvested, as this may increase the detection of lymphatic metastases.

Diagnostic Efficacy of Sentinel Lymph Node Biopsy in Early Oral Squamous Cell Carcinoma: A Meta-Analysis of 66 Studies

OBJECTIVES

The diagnostic efficacy of sentinel lymph node biopsy(SLNB) in early oral squamous cell carcinoma(OSCC) still remains controversial. This meta-analysis was conducted to assess the diagnostic value of SLNB in clinically neck-negative T1-2 OSCC.

METHODS

A systematic literature search for relevant literature published up to September 11, 2016 was conducted in PubMed, Embase, Web of Science, Cochrane Library and ClinicalTrials, and the reference lists of eligible studies were examined. Data from different studies were pooled to estimate the summary sentinel lymph node(SLN) identification rate, sensitivity, negative predictive value. Summary receiver operator characteristic curve(SROC) was plotted and area under the SROC curve (AUC) was calculated to evaluate the overall diagnostic efficacy. Threshold effect was assessed with use of the spearman correlation coefficient. Between-study heterogeneity was tested using the Q tests and the I2 statistics. Subgroup analyses were conducted in view of the greater effect of different study characteristics on diagnostic efficacy of SLN. Deeks' funnel plot asymmetry test was performed to evaluate publication bias. Sensitivity analysis was evaluated through omitting studies one by one and comparing the pooled results of random-effects model and fixed-effects model. All analyses were performed using Review Manager (version 5.3.5), Meta-DiSc (version 1.4), Comprehensive Meta Analysis (version 2.0) and STATA (version 12).

RESULTS

66 studies comprising 3566 patients with cT1-2N0 OSCC were included in this meta-analysis. The pooled SLN identification rate was 96.3%(95% CI: 95.3%-97.0%). The pooled sensitivity was 0.87 (95% CI: 0.85-0.89), pooled negative predictive value was 0.94 (95% CI: 0.93-0.95), and AUC was 0.98 (95% CI: 0.97-0.99). Subgroup analyses indicated that SLN assessment with immunohistochemistry(IHC) achieved a significantly higher sensitivity than without IHC.

CONCLUSIONS

This meta-analysis suggests that SLNB has a high diagnostic accuracy in cT1-2N0 oral squamous cell carcinoma, and is an ideal alternative to elective neck dissection. Furthermore, the use of IHC can significantly improve SLNB diagnostic sensitivity for early OSCC.

Feasibility of Real-Time Near-Infrared Fluorescence Tracer Imaging in Sentinel Node Biopsy for Oral Cavity Cancer Patients

Background

Sentinel node biopsy (SNB) is an established method in oral squamous cell carcinoma (OSCC) for staging the cN0 neck and to select patients who will benefit from a neck dissection. Near-infrared fluorescence (NIRF) imaging has the potential to improve the SNB procedure by facilitating intraoperative visual identification of the sentinel lymph node (SN). The purpose of this study was to evaluate the feasibility of fluorescence tracer imaging for SN detection in conjunction with conventional radio-guided technique.

Methods

Prospective study of patients with primary OSCC planned for tumor resection and SNB. Thirty patients were injected peritumorally with a bimodal tracer (ICG-^99mTc-Nanocoll) followed by lymphoscintigraphy and SPECT/CT to define the SNs and their anatomical location preoperatively. SNs were detected intraoperatively with a hand-held gamma-probe and a hand-held NIRF camera.

Results

In 29 of 30 subjects (97%), all preoperatively defined SNs could be identified intraoperatively using a combination of radioactive and fluorescence guidance. A total of 94 SNs (mean 3, range 1–5) that were both radioactive and fluorescent ex vivo were harvested. Eleven of 94 SNs (12%) could only be identified in vivo using NIRF imaging, and the majority of those were located in level 1 close to the primary tumor.

Conclusions

A combined fluorescent and radioactive tracer for SNB is feasible, and the additional use of NIRF imaging may improve the accuracy of SN identification in oral cancer patients. Intraoperative fluorescence guidance seems of particular value when SNs are located in close proximity to the injection site.

Sentinel lymph node biopsy in oral and oropharyngeal squamous cell carcinoma: current status and unresolved challenges

Because imaging with ultrasound, computed tomography, magnetic resonance imaging or positron emission tomography is unreliable for preoperative lymph node staging of early-stage oral and oropharyngeal squamous cell carcinoma (OSCC), elective neck dissection has been typically performed. The targeted sampling of sentinel lymph nodes (SLN) identified by lymphoscintigraphy and detected by gamma probe has become an effective alternative for the selection of patients for regional nodal resection. With careful consideration to technique, high SLN detection rates have been reported. Advanced techniques including intraoperative handheld gamma camera imaging and freehand single photon emission computed tomography (SPECT) are expected to increase surgical confidence in these procedures. This review gives an update on SLN biopsy in patients with OSCC including clinical standards and controversial aspects.

Practice variation in defining sentinel lymph nodes on lymphoscintigrams in oral cancer patients

PURPOSE

Lymphoscintigraphic imaging and adequate interpretation of the lymphatic drainage pattern is an essential step in the sentinel lymph node biopsy (SLNB) procedure. In oral cancer, identification of the sentinel lymph node (SLN) can be challenging. In this study, interobserver variability in defining SLNs on lymphoscintigrams was evaluated in patients with T1-T2 stage N0 oral cancer.

METHODS

Sixteen observers (head and neck surgeons, nuclear medicine physicians or teams of both) from various institutes were asked which criteria they use to consider a hot focus on the lymphoscintigram as SLN. Lymphoscintigrams of 9 patients with 47 hot foci (3-9 per patient) were assessed, using a scale of 'yes/equivocal/no'. Bilateral drainage was seen in four of nine cases. In three cases additional late single photon emission computed tomography (SPECT)/CT scanning was performed. Interobserver variability was evaluated by kappa (к) analysis, using linear weighted pairwise comparison of the observers. Conservative (equivocal analysed as no) and sensitive (equivocal analysed as yes) assessment strategies were investigated using pairwise kappa analysis.

RESULTS

Various definitions of SLN on lymphoscintigrams were given. Interobserver variability of all cases using a 3-point scale showed fair agreement (71%, к(w) = 0.29). The conservative and sensitive analyses both showed moderate agreement: conservative approach к = 0.44 (in 80% of the hot foci the observers agreed) and sensitive approach к = 0.42 (81%) respectively. Multidisciplinary involvement in image interpretation and higher levels of observer experience appeared to increase agreement.

CONCLUSION

Among 16 observers, there is practice variation in defining SLNs on lymphoscintigrams in oral cancer patients. Interobserver variability of lymphoscintigraphic interpretation shows moderate agreement. In order to achieve better agreement in defining SLNs on lymphoscintigrams specific guidelines are warranted.

An innovative multimodality approach for sentinel node mapping and biopsy in head and neck malignancies

PURPOSE

Recent innovations such as preoperative SPECT/CT, intraoperative imaging using portable devices and a hybrid tracer were evaluated in a multimodality approach for sentinel node (SN) mapping and biopsy in head and neck malignancies.

MATERIAL AND METHODS

The evaluation included 25 consecutive patients with head and neck malignancies (16 melanomas and 9 oral cavity squamous cell carcinomas). Patients were peritumorally injected with the hybrid tracer ICG-(99m)Tc-nanocolloid. SNs were initially identified with lymphoscintigraphy followed by single photon emission computed tomography (SPECT/CT) 2 hours after tracer administration. During surgery a portable gamma camera in combination with a near-infrared fluorescence camera was used in addition to a handheld gamma ray detection probe to locate the SNs.

RESULTS

In all patients the use of conventional lymphoscintigraphy, SPECT/CT and the additional help of the portable gamma camera in one case were able to depict a total of 67 SNs (55 of them visualized on planar images, 11 additional on SPECT/CT and 1 additional with the portable gamma camera). A total of 67 of the preoperatively defined SNs together with 22 additional SNs were removed intraoperatively; 12 out of the 22 additional SNs found during operation were located in the vicinity of the injection site in anatomical areas such as the periauricular or submental regions. The other 10 additional SNs were found by radioguided post-resection control of the excision SN site.

CONCLUSION

In the present series 26% additional SNs were found using the multimodal approach, that incorporates SPECT/CT and intraoperative imaging to the conventional procedure. This approach appears to be useful in malignancies located close to the area of lymphatic drainage such as the periauricular area and the oral cavity.

Use of a novel receptor-targeted (CD206) radiotracer, 99mTc-tilmanocept, and SPECT/CT for sentinel lymph node detection in oral cavity squamous cell carcinoma: initial institutional report in an ongoing phase 3 study

IMPORTANCE

Sentinel lymph node biopsy has been proposed as an alternative to up-front elective neck dissection (END) for determination of pathologic nodal status in patients undergoing surgical treatment for oral cavity squamous cell carcinoma (OSCC) with clinically negative neck (cN0). Sentinel lymph node biopsy using current standard tracer agents and imaging adjuncts such as radiolabeled sulfur-colloid and planar lymphoscintigraphy (LS), however, is associated with several drawbacks.

OBJECTIVE

To assess the preliminary utility of technetium Tc 99m (99mTc)-tilmanocept, a novel molecular imaging agent for sentinel lymph node (SLN) mapping, in OSCC.

DESIGN, SETTING, AND PARTICIPANTS

Prospective, nonrandomized, single-arm, part of an ongoing phase 3 clinical trial. Patients had previously untreated, clinically and radiographically node-negative OSCC (T1-4aN0M0) at an academic tertiary referral center.

INTERVENTIONS

Patients received a single dose of 50 µg 99mTc-tilmanocept injected peritumorally followed by dynamic planar LS and fused single-photon emission computed tomography/computed tomography (SPECT/CT) prior to surgery. Surgical intervention consisted of excision of the primary tumor and radioguided SLN dissection followed by planned END. The excised lymph nodes (SLNs and non-SLNs) underwent histopathologic evaluation for presence of metastatic disease.

MAIN OUTCOMES AND MEASURES

False-negative rate and negative predictive value of SLNB using 99mTc-tilmanocept and comparison of planar LS with SPECT/CT in SLN localization.

RESULTS

Twelve of 20 patients (60%) had metastatic neck disease on pathologic examination. All 12 had at least 1 SLN positive for metastases. No patients had a positive END node who did not have at least 1 positive SLN. These data yield a false-negative rate of 0% and negative predictive value of 100% using 99mTc-tilmanocept in this setting. Dynamic planar LS and SPECT/CT revealed a mean (range) number of hot spots per patient of 2.9 (1-7) and 3.7 (1-12), respectively. Compared with planar LS, SPECT/CT identified additional putative SLNs in 11 of 20 cases (55%).

CONCLUSIONS AND RELEVANCE

The high negative predictive value and low false-negative rate in identification of occult metastases shows 99mTc-tilmanocept to be a promising agent in SLN identification in patients with OSCC. Use of SPECT/CT improves preoperative SLN localization including delineation of SLN locations near the primary tumor when compared with planar LS imaging.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT00911326.

SPECT/CT in sentinel node imaging

Sentinel node lymphoscintigraphy and biopsy has become standard practice for lymphatic staging in early-stage breast cancer and melanoma. More recently, sentinel node lymphoscintigraphy has also been used in head and neck squamous cell cancers and other solid tumours. Single photon emission computed tomography/computed tomography (SPECT/CT) is a new tool and this article reviews its potential application in sentinel node imaging. SPECT/CT provides complementary functional and anatomical information and has been shown to be superior to planar imaging in a number of indications. The advantages include more accurate anatomical localization, identification of false positives (due to contamination or spillover from the injection site), reduction in the number of false negatives (visualization of nodes not seen on planar imaging) and alteration of the surgical approach. We thus believe that sentinel lymph node SPECT/CT can provide valuable information before sentinel lymph node biopsy and advocate its use in a range of tumours such as truncal and head and neck melanomas.

Visualization of the sentinel node in early-stage oral cancer: limited value of late static lymphoscintigraphy

OBJECTIVE

Various lymphoscintigraphic imaging protocols exist for sentinel node (SN) identification in early-stage oral cancer. This study aimed to evaluate the clinical value of performing additional late lymphoscintigraphic imaging.

METHODS

We retrospectively analysed early (directly following injection of 99mTc-Nanocoll) and late (2-4 h after injection) imaging results of 60 early-stage (T1-T2, cN0) oral cancer patients scheduled for SN procedure. Lymphoscintigraphic results of late imaging were categorized into: (a) no visualization of additional hotspots considered to be SNs; (b) additional hotspots visualized that are considered to be SNs and (c) hotspots visualized only during late imaging. Histopathological results of the harvested SNs were related to the corresponding hotspot.

RESULTS

In all patients (n=60) lymphoscintigraphy was able to visualize a hotspot that was identified as an SN. In 51/60 (85%) patients, early imaging was able to visualize at least one hotspot, whereas in 9/60 (15%) patients, mostly with oral cavity tumours other than mobile tongue and floor-of-mouth tumours, only late imaging was able to visualize hotspots. In 14/51 (27%) patients, late imaging resulted in additionally visualized hotspots marked as SNs, resulting in a more extensive surgical procedure. These additionally removed SNs appeared to be of no clinical relevance, as all SNs identified during early imaging correctly predicted whether the neck was positive or negative for cancer.

CONCLUSION

Results of this study indicate that additional late lymphoscintigraphic imaging should be performed only in selected cases.

89Zr-nanocolloidal albumin-based PET/CT lymphoscintigraphy for sentinel node detection in head and neck cancer: preclinical results

Identifying sentinel nodes near the primary tumor remains a problem in, for example, head and neck cancer because of the limited resolution of current lymphoscintigraphic imaging when using (99m)Tc-nanocolloidal albumin. This study describes the development and evaluation of a nanocolloidal albumin-based tracer specifically dedicated for high-resolution PET detection.

METHODS

(89)Zr was coupled to nanocolloidal albumin via the bifunctional chelate p-isothiocyanatobenzyldesferrioxamine B. Quality control tests, including particle size measurements, and in vivo biodistribution and imaging experiments in a rabbit lymphogenic metastasis model were performed.

RESULTS

Coupling of (89)Zr to nanocolloidal albumin appeared to be efficient, resulting in a stable product with a radiochemical purity greater than 95%, without affecting the particle size. PET showed distinguished uptake of (89)Zr-nanocolloidal albumin in the sentinel nodes, with visualization of lymphatic vessels, and with a biodistribution comparable to (99m)Tc-nanocolloidal albumin.

CONCLUSION

(89)Zr-nanocolloidal albumin is a promising tracer for sentinel node detection by PET.

Hybrid imaging (SPECT/CT and PET/CT)--improving the diagnostic accuracy of functional/metabolic and anatomic imaging

In-line combined systems, single-photon emission computed tomography (SPECT)/computed tomography (CT) and positron emission tomography (PET)/CT, allow an instant generation of fused images of scintigraphy and CT data. The accumulated clinical data on the use of these systems in various clinical scenarios indicate that this hybrid technology improves the diagnostic accuracy as compared to scintigraphy and CT alone and even to side-by-side interpretation of scintigraphy and CT, which were acquired separately. The improved diagnostic accuracy is reflected by improving image quality of SPECT and PET, detection of more clinically relevant lesions, better localization of disease and differentiation between physiologic and pathologic uptake, characterization of disease by its functional and morphologic appearance before and after therapy and accurate delineation of disease, optimizing biopsy and therapy planning.

SPECT/CT for Lymphatic Mapping of Sentinel Nodes in Early Squamous Cell Carcinoma of the Oral Cavity and Oropharynx

Adequate staging and treatment of the neck in squamous cell carcinoma of the oral cavity and oropharynx (OSCC) is of paramount importance. Elective neck dissection (END) of the clinical N0-neck is widely advocated as neck treatment. With regard to the prevalence of 20–40% of occult neck metastases found in the ND specimens, the majority of patients undergo surgery of the lymphatic drainage basin without therapeutic benefit. Sentinel node biopsy (SNB) has been shown to be a safe, reliable and accurate alternative treatment modality for selected patients. Using this technique, lymphatic mapping is crucial. Previous reports suggested a benefit of single photon emission computed tomography with CT (SPECT/CT) over dynamic planar lymphoscintigraphy (LS) alone. SPECT/CT allows the surgeon for better topographical orientation and delineation of sentinel lymph nodes (SLN's) against surrounding structures. Additionally, SPECT/CT has the potential to detect more SLN's which might harbour occult disease, than LS. SPECT/CT is recommended to be used routinely, although SPECT/CT is not indispensable for successful SNB.

Joint practice guidelines for radionuclide lymphoscintigraphy for sentinel node localization in oral/oropharyngeal squamous cell carcinoma

Involvement of the cervical lymph nodes is the most important prognostic factor for patients with oral/oropharyngeal squamous cell carcinoma (OSCC), and the decision whether to electively treat patients with clinically negative necks remains a controversial topic. Sentinel node biopsy (SNB) provides a minimally invasive method of determining the disease status of the cervical node basin, without the need for a formal neck dissection. This technique potentially improves the accuracy of histological nodal staging and avoids over-treating three-quarters of this patient population, minimizing associated morbidity. The technique has been validated for patients with OSCC, and larger-scale studies are in progress to determine its exact role in the management of this patient population. This article was designed to outline the current best practice guidelines for the provision of SNB in patients with early-stage OSCC, and to provide a framework for the currently evolving recommendations for its use. These guidelines were prepared by a multidisciplinary surgical/nuclear medicine/pathology expert panel under the joint auspices of the European Association of Nuclear Medicine (EANM) Oncology Committee and the Sentinel European Node Trial Committee.

SPECT/CT for preoperative sentinel node localization

The value of SPECT/CT for detection and localization of sentinel nodes is reviewed. SPECT/CT depicts extra sentinel nodes and identifies non-nodal tracer accumulation. SPECT/CT is indicated in patients with complex lymphatic drainage as often present in patients with head, neck and scapular melanoma, breast cancer patients with extra-axillary sentinel nodes and patients with tumors draining to pelvic nodes. SPECT/CT also clarifies the drainage pattern of inconclusive conventional images (non-visualization or unclear location of the nodes).

Paraaortic sentinel lymph nodes: toward optimal detection and intraoperative localization using SPECT/CT and intraoperative real-time imaging

Paraaortic sentinel node biopsy may be a challenging procedure because the sentinel nodes are located retroperitoneally in close proximity to vital structures. The purpose of this study was to describe and evaluate the value of preoperative SPECT/CT for lymphatic mapping, and a portable gamma-camera for intraoperative radioguidance, in patients with paraaortic sentinel nodes.

METHODS

We evaluated our practice in 18 patients, who were treated at The Netherlands Cancer Institute with sentinel lymphadenectomy for different urologic malignancies and showed paraaortic drainage on preoperative images. After intratumoral injection of (99m)Tc-nanocolloid, the patients underwent sequential planar lymphoscintigraphy, hybrid SPECT/CT, and sentinel lymphadenectomy. Intraoperative node detection and localization were guided by a laparoscopic gamma-probe and a portable gamma-camera. This gamma-camera was set to display both the (99m)Tc signal and the (125)I-seed signal. This (125)I seed was placed on top of the gamma-probe, functioning as a pointer on screen, thus enabling real-time sentinel node localization with the gamma-camera.

RESULTS

In 16 patients with midabdominal drainage on planar images and in 2 patients with nonvisualization on planar images, SPECT/CT showed clear localization of paraaortic sentinel nodes in relation to the abdominal vessels. Five patients underwent open surgery, and 13 patients underwent laparoscopy. The paraaortic sentinel nodes were successfully localized and removed in 15 patients with the help of the portable gamma-camera and gamma-probe and in 3 patients with the gamma-probe only. In 1 patient, the paraaortic sentinel node showed a metastasis.

CONCLUSION

If retroperitoneal drainage is expected, SPECT/CT provides good detection and clear localization of sentinel nodes in relation to anatomic structures. Detection and removal of paraaortic sentinel nodes by means of a laparoscopic gamma-probe and real-time imaging with a portable gamma-camera is a successful method with high intraoperative detection rates.

Sentinel node detection in head and neck malignancies: innovations in radioguided surgery

Sentinel node mapping is becoming a routine procedure for staging of various malignancies, because it can determine lymph node status more precisely. Due to anatomical problems, localizing sentinel nodes in the head and neck region on the basis of conventional images can be difficult. New diagnostic tools can provide better visualization of sentinel nodes. In an attempt to keep up with possible scientific progress, this article reviews new and innovative tools for sentinel node localization in this specific area. The overview comprises a short introduction of the sentinel node procedure as well as indications in the head and neck region. Then the results of SPECT/CT for sentinel node detection are described. Finally, a portable gamma camera to enable intraoperative real-time imaging with improved sentinel node detection is described.

Joint Practice Guidelines for Radionuclide Lymphoscintigraphy for Sentinel Node Localization in Oral/Oropharyngeal Squamous Cell Carcinoma

Involvement of the cervical lymph nodes is the most important prognostic factor for patients with oral/oropharyngeal squamous cell carcinoma (OSCC), and the decision of whether to electively treat patients with clinically negative necks remains a controversial topic. Sentinel node biopsy (SNB) provides a minimally invasive method for determining the disease status of the cervical node basin, without the need for a formal neck dissection. This technique potentially improves the accuracy of histologic nodal staging and avoids overtreating three-quarters of this patient population, minimizing associated morbidity. The technique has been validated for patients with OSCC, and larger-scale studies are in progress to determine its exact role in the management of this patient population. This document is designed to outline the current best practice guidelines for the provision of SNB in patients with early-stage OSCC, and to provide a framework for the currently evolving recommendations for its use. Preparation of this guideline was carried out by a multidisciplinary surgical/nuclear medicine/pathology expert panel under the joint auspices of the European Association of Nuclear Medicine (EANM) Oncology Committee and the Sentinel European Node Trial (SENT) Committee.

Is there an additional value of SPECT/CT over planar lymphoscintigraphy for sentinel node mapping in oral/oropharyngeal squamous cell carcinoma?

BACKGROUND

Lymphatic mapping for sentinel node biopsy (SNB) has been shown to be crucial for detection of sentinel lymph nodes (SLN). Previous reports suggested a benefit of single photon emission computed tomography with CT (SPECT/CT) over dynamic planar lymphoscintigraphy (LS) alone. The aim was to assess whether there is an additional value of SPECT/CT over LS alone for lymphatic mapping of SLNs in oral/oropharyngeal SCC.

METHODS

A consecutive cohort of 58 patients was evaluated using SNB with additional SPECT/CT to preoperative LS.

RESULTS

In the entire cohort of 58 patients undergoing LS and SPECT/CT, hot spots could be revealed in all but 4 cases. The guidance of the handheld gamma probe was able to reveal 9 additional SLNs within 3 patients not detected by either modality. Lymphoscintigraphy showed full concordance with SPECT/CT in 81% of the cases. SPECT/CT was able to detect additional HS in 11 patients, in 1 case even with additional metastatic disease. The false negative rate for SNB was 6%, and the negative predictive value 98%.

CONCLUSIONS

SPECT/CT has the potential to detect more SLNs, which might harbor occult disease, than LS alone. With regard to the excellent results achieved with LS and the intraoperative use of the gamma probe, SPECT/CT is not indispensable for successful SNB. Both imaging modalities have difficulties in detecting level I sentinel nodes close to the injection site.

Value of SPECT/CT for detection and anatomic localization of sentinel lymph nodes before laparoscopic sentinel node lymphadenectomy in prostate carcinoma

Laparoscopic evaluation of sentinel nodes is useful for staging prostate cancer, but preoperative localization of deep abdominal sentinel nodes with planar lymphoscintigraphy is difficult. We evaluated the value of SPECT/CT for detecting and localizing sentinel nodes in prostate cancer.

METHODS

(99m)Tc-nanocolloid was injected peri- and intratumorally, guided by transrectal ultrasonography, in 46 patients with prostate cancer of intermediate prognosis. Patients underwent planar imaging after 15 min and 2 h, SPECT/CT after 2 h, and laparoscopic sentinel node lymphadenectomy on the same day. SPECT was fused with CT and analyzed using 2-dimensional orthogonal slicing and 3-dimensional volume rendering. We evaluated the number of extra sentinel nodes found by SPECT/CT, the number of sentinel nodes found by SPECT/CT outside the area of the extended pelvic lymphadenectomy, and the anatomic information provided by SPECT/CT. Furthermore, we classified the value of the additional SPECT/CT images into 3 categories (no advantage, presumable advantage, and definite advantage) according to the extra anatomic information given and whether additional sentinel nodes were found by SPECT/CT.

RESULTS

The patients had a mean age of 64 y (range, 53-74 y) and received a mean injected dose of 218 MBq (range, 147-286 MBq). The sentinel node visualization rate was 91% (42 patients) for planar imaging and 98% (45 patients) for SPECT/CT. In 29 of the 46 patients (63%), SPECT/CT revealed additional sentinel nodes (especially lymph nodes near the injection area) not seen on planar imaging. In 7 patients, those additional sentinel nodes were positive for metastasis (being the exclusive metastatic sentinel node in 4 patients). Overall, 15 patients (33%) had positive sentinel nodes. Sentinel nodes outside the area of extended pelvic lymphadenectomy were found in 16 patients (35%), whereas in 56% of these patients those nodes were not seen on planar imaging. Performing SPECT/CT had no advantage in 13% of the patients, a presumable advantage in 24%, and a definite advantage in 63%. Urologic surgeons used the SPECT/CT images to guide their trocar insertion sites and sentinel node finding with the probe.

CONCLUSION

More sentinel nodes can be detected with SPECT/CT than with planar imaging alone. In comparison with planar imaging, SPECT/CT especially reveals extra sentinel nodes near the prostate and outside the area of the extended pelvic lymphadenectomy. Furthermore, the modality provides useful additional information about the anatomic location of sentinel nodes within and outside the pelvic area, leading to improved intraoperative sentinel node identification.

Comparative study of patients with and without sentinel lymph node biopsy (SLNB) in oral and oropharyngeal cancer: is SLNB an accurate and useful procedure?

CONCLUSION

Sentinel lymph node biopsy (SLNB) is a technique that facilitates the study of metastasis in oral and oropharyngeal cancer and reduces morbidity in patients affected by this pathology.

OBJECTIVES

Oral and oropharyngeal cancers are common and are frequently associated with spread to cervical lymph nodes. We attempted to confirm the usefulness of SLNB in patients suffering from squamous cell carcinoma of the oral cavity as a prognostic technique for lymph node prediction of micrometastatic invasion. Using surgical parameters, we compared its relevance against a retrospective group without SLNB.

PATIENTS AND METHODS

We studied a prospective group of 22 patients, 21 men and 1 woman, aged 40-83 years (mean=57.77, SD=13) in which SLNB was performed and a retrospective group of 22 patients, 19 men and 3 women, aged 34-76 years (mean=52.68, SD=11) in which SLNB was not performed. Both groups presented oral cavity tumors at clinical stages T1-T3 and radiological stage N0. SLNB consisted of preoperative lymphoscintigraphy (LG), intraoperative detection of the sentinel lymph node (SLN), and a histopathological examination following the recommendations of the Association of Directors of Anatomic and Surgical Pathology (ADASP) and the Canniesburn protocol.

RESULTS

We observed SLNs in 21 of 22 patients, with a total of 32 SLNs detected at cervical level II (65.63%), I (21.87%), and III (12.5%). SLNB displayed a sensitivity of 73% (confidence interval (CI)=0.51-0.99) and 100% specificity (CI=1). Negative and positive predictive values were 80% and 100%, respectively. SLNB significantly reduced the incidence of radical neck dissection (p=0.003), the need for recovery/resuscitation beds after surgery (p=0.002), surgical complications (p=0.034), and length of hospital stay (p=0.01).

SPECT/CT imaging: clinical utility of an emerging technology

Single-photon emission computed tomography (SPECT) has been a mainstay of nuclear medicine practice for several decades. More recently, combining the functional imaging available with SPECT and the anatomic imaging of computed tomography (CT) has gained more acceptance and proved useful in many clinical situations. Most vendors now offer integrated SPECT/CT systems that can perform both functions on one gantry and provide fused functional and anatomic data in a single imaging session. In addition to allowing anatomic localization of nuclear imaging findings, SPECT/CT also enables accurate and rapid attenuation correction of SPECT studies. These attributes have proved useful in many cardiac, general nuclear medicine, oncologic, and neurologic applications in which the SPECT results alone were inconclusive. Optimal clinical use of this rapidly emerging imaging modality requires an understanding of the fundamental principles of SPECT/CT, including quality control issues as well as potential pitfalls and limitations. The long-term clinical and economic effects of this technology have yet to be established.

SPECT/CT

In view of the commercial success of integrated PET/CT scanners, there is an increasing interest in comparable SPECT/CT systems. SPECT in combination with CT enables a direct correlation of anatomic information and functional information, resulting in better localization and definition of scintigraphic findings. Besides anatomic referencing, the added value of CT coregistration is based on the attenuation correction capabilities of CT. The number of clinical studies is limited, but pilot studies have indicated a higher specificity and a significant reduction in indeterminate findings. The superiority of SPECT/CT over planar imaging or SPECT has been demonstrated in bone scintigraphy, somatostatin receptor scintigraphy, parathyroid scintigraphy, and adrenal gland scintigraphy. Also, rates of detection of sentinel nodes by biopsy can be increased with SPECT/CT. This review highlights recent technical developments in integrated SPECT/CT systems and summarizes the current literature on potential clinical uses and future directions for SPECT/CT in cardiac, neurologic, and oncologic applications.

Need for intensive histopathologic analysis to determine lymph node metastases when using sentinel node biopsy in oral cancer

OBJECTIVE

To determine the predictive value of sentinel node biopsy (SNB)-assisted neck dissection in patients with oral squamous cell carcinoma (SCC) stage T1 to 2N0M0 and to determine the incidence of subclinical metastases.

STUDY DESIGN

Prospective cohort study.

METHODS

Fifty-one patients with clinically N0 neck underwent SNB-assisted neck dissection. The localization of the sentinel node (SN) was determined using dynamic and planar lymphoscintigraphy and single photon emission computed tomography-computed tomography. Histopathologic examination of the harvested SN was performed using step-serial sectioning with hematoxylin-eosin (H&E) and immunohistochemistry on formalin-fixed, paraffin-embedded tissue.

RESULTS

A total of 181 SNs were excised with a median of 3 (range 1-7) SNs per patient. Four percent (2 of 51) of patients with subclinical (occult) lymph node metastasis would have been identified using routine H&E staining, whereas the 18% (9 of 49) were upstaged as a result of additional histopathology when the H&E evaluation was negative. Overall, the incidence of subclinical metastases was 22% (11 of 51).

CONCLUSION

In this study, SNB-assisted neck dissection proved to be technically feasible in identifying subclinical metastasis, thus accurately staging the neck with a high degree of sensitivity in patients with oral SCC T1 to 2N0M0 when additional histopathology was performed. The vast majority of patients in this study would have been spared selective neck dissection had reliance on SNB been used and selective neck dissection performed only in the case of a positive SN. Future studies should focus on determining whether SNB alone reduces patient morbidity and whether this is as equally effective in the treatment of cervical nodal metastases as compared with selective neck dissection in patients with oral SCC.

The single-photon emission computed tomography/computed tomography: a new procedure to perform the sentinel node biopsy in patients with head and neck melanoma

The aim of this study was to define and validate a new technique to detect the sentinel node (SN) in patients treated for head and neck melanoma. In a small series of 23 head and neck melanoma patients, lymphatic mapping was followed by SN biopsy, using in 12 patients a new diagnostic imaging technique, single-photon emission computed tomography/computed tomography. The procedure is described and the major problems encountered are discussed. The preliminary data show that identification of SN using single-photon emission computed tomography/computed tomography never failed in 12 patients, and biopsies performed, compared with those in a standard group, took significantly less time (Mann-Whitney test P=0.006). In conclusion, the authors underline the possibility of a wide use for this technique.

Überleben mit hämatogen metastasierten HNO-Tumoren

QUESTIONS

The objective of this retrospective analysis was to investigate parameters with a potential impact on survival in a collective of 114 patients with distant metastatic disease after head and neck cancer.

PATIENTS AND METHODS

The primary endpoint was the survival with distant metastatic disease, the secondary endpoint was overall survival. Primary therapy, local recurrence, second neoplasms, palliative chemotherapy (CHT) and radiotherapy (RT), as well as Karnofsky performance status (KPS) at the time of diagnosis of the metastases were analyzed as potential impact parameters using the log-rank test with subsequent Cox regression analysis.

RESULTS

Palliative CHT (P=0.0020) and KPS (P=0.0011) had a significant positive impact on the median survival probability with metastases (8.2 months) using the log-rank test, KPS at the time of diagnosis of metastases remained as an independent prognostic parameter in the Cox regression (P=0.0013). Primary therapy, local tumor control and KPS had a significant positive influence on the median overall survival probability (18.5 months) univariately (P=0.0139, P=0.0106, P= 0.0096) and multivariately (P=0.0123, and P=0.0063, P=0.0197, respectively).

CONCLUSIONS

KPS at the time of diagnosis of metastases is an independent prognostic parameter for both endpoints. Lacking evidence for life prolongation, palliative therapies should therefore first and foremost focus on the stabilization of the KPS.