The yield of SPECT/CT for anatomical lymphatic mapping in patients with melanoma

The realization of medical devices for precision surgery - development and implementation of 'stop-and-go' imaging technologies

INTRODUCTION

Surgery and biomedical imaging encompass a big share of the medical-device market. The ever-mounting demand for precision surgery has driven the integration of these two into the field of image-guided surgery. A key-question herein is how imaging modalities can guide the surgical decision-making process. Through performance-based design, chemists, engineers, and doctors need to build a bridge between imaging technologies and surgical challenges.

AREAS-COVERED

This perspective article highlights the complementary nature between the technological design of an image-guidance modality and the type of procedure performed. The specific roles of the involved professionals, imaging technologies, and surgical indications are addressed.

EXPERT-OPINION

Molecular-image-guided surgery has the potential to advance pre-, intra- and post-operative tissue characterization. To achieve this, surgeons need the access to well-designed indication-specific chemical-agents and detection modalities. Hereby, some technologies stimulate exploration ('go'), while others stimulate caution ('stop'). However, failing to adequately address the indication-specific needs rises the risk of incorrect tool employment and sub-optimal surgical performance. Therefore, besides the availability of new technologies, market growth is highly dependent on the practical nature and impact on real-life clinical care. While urology currently takes the lead in the widespread implementation of image-guidance technologies, the topic is generic and its popularity spreads rapidly within surgical oncology.

Single-Photon Emission Computed Tomography/Computed Tomography Utilization for Extremity Melanomas at a High-Volume Center

INTRODUCTION

Planar lymphoscintigraphy (PL) is commonly used in mapping before sentinel lymph node biopsy (SLNB) for invasive cutaneous melanoma. Recently, single-photon emission computed tomography (SPECT)/ computed tomography (CT) has been utilized, in addition to PL, for detailed anatomic information and detection of sentinel lymph nodes (SLNs) outside of the primary nodal basin in truncal and head and neck melanoma. Following a protocol change due to COVID-19, our institution began routinely obtaining both PL and SPECT-CT imaging for all melanoma SLN mapping. We hypothesized that SPECT-CT is associated with higher instances of SLNBs from "nontraditional" nodal basins (NTNB) for extremity melanomas.

METHODS

Patients with extremity melanoma (2017-2022) who underwent SLNB were grouped into SPECT-CT with PL versus PL alone. Outcomes were total SLNs removed, + or-SLN status, total NTNB sampled, and postoperative complication rate. Poisson regression and logistic regression models were used to assess association of SPECT-CT with patient outcomes.

RESULTS

Of 380 patients with extremity melanoma, 42.11% had SPECT-CT. There were no differences between the groups with regards to age at diagnosis or sex. From 2020 to 2022, all patients underwent SPECT-CT. SPECT-CT was associated with increased odds of SLNB from an NTNB, (odds ratio = 2.39 [95% confidence interval: 1.25-4.67]). There was no difference in odds of number of SLNs sampled, SLN positivity rate, or postoperative complication rate with SPECT-CT.

CONCLUSIONS

Routine SPECT-CT was associated with higher incidence of SLNB in NTNB but did not increase number of SLNs removed or SLN positivity rate. The added value of routine SPECT-CT in cutaneous melanoma of the extremities remains to be defined.

Evaluation of Preoperative and Intraoperative Mobile Gamma Camera Imaging in Sentinel Lymph Node Biopsy for Melanoma Independent of Preoperative Lymphoscintigraphy

INTRODUCTION

Sentinel lymph node biopsy (SLNB) is a standard practice for staging cutaneous melanoma. High false-negative rates have an increased interest in adjunctive techniques for localizing SLNs. Mobile gamma cameras (MGCs) represent potential tools to enhance SLNB performance.

METHODS

An institutional review board approval was obtained for this study (ClinicalTrials.gov ID NCT01531608). After obtaining informed consent, 20 eligible melanoma patients underwent 99mTc sulfur colloid injection and standard lymphoscintigraphy with a fixed gamma camera (FGC). A survey using a 20 cm square MGC, performed immediately preoperatively by the study surgeon, was used to establish an operative plan while blinded to the FGC results. Subsequently, SLNB was performed using a gamma probe and a novel 6 cm diameter handheld MGC.

RESULTS

A total of 24 SLN basins were detected by FGC. Prior to unblinding, all 24 basins were identified with the preoperative MGC and the operative plan established by preoperative MGC imaging was confirmed accurate by review of the FGC images. All individual sentinel lymph nodes were identified during intraoperative MGC imaging, and in 5/24 (21%) cases, surgeon-reported additional clinically useful information was obtained from the MGC.

CONCLUSIONS

Preoperative MGC images provide information consistent with FGC images for planning SLNB and in some cases provide additional information that aided in surgical decision-making.

Nonvisualized sentinel node on preoperative lymphoscintigraphy in primary cutaneous melanoma: an 11-year retrospective survey

BACKGROUND

Sentinel lymph node (SLN) biopsy in cutaneous melanoma patients evaluates the regional draining basin for occult micrometastatic disease. Occasionally, nonidentification of SLN impairs the acquisition of this important prognostic factor.

OBJECTIVES

To investigate the outcomes of melanoma patients with negative lymphoscintigraphic findings and patients who underwent SLN biopsy from 2004 to 2015 ( n  = 1200) were retrospectively reviewed for tumor characteristics and clinical outcomes.

METHODS

Patients with nonvisualized lymph nodes (NV group) who underwent only preoperative lymphoscintigraphy were separated and compared with a cohort drawn from all melanoma patients who completed the surgical procedure within the same period (V group).

RESULTS

A negative lymphoscintigraphic scan was observed in 38 cases (3.2% of all patients). The NV group showed a significantly older age (median 66.0 vs. 48.3 years; P  < 0.0001). Head and neck melanomas were more frequent in the NV group compared to the control group (25.1 vs. 7.8%; P  = 0.009). Tumor characteristics such as ulceration and Breslow thickness do not influence the lymphoscintigraphy result. No differences were found in overall survival (OS) and disease-free survival (DFS) between the groups.

CONCLUSIONS

The nonvisualization of regional lymph nodes by lymphoscintigraphy is more frequent in older patients with head and neck melanomas. From the clinical point of view, no specific recommendation emerged for patients' management because the nonvisualization of the SLN did not show a significant influence on DFS and OS rates. However, lack of knowledge of lymph node status suggests performing a tighter follow-up eventually by ultrasound evaluation of all potential lymph node drainage basins.

Skin Cancer Pathobiology at a Glance: A Focus on Imaging Techniques and Their Potential for Improved Diagnosis and Surveillance in Clinical Cohorts

Early diagnosis is essential for completely eradicating skin cancer and maximizing patients' clinical benefits. Emerging optical imaging modalities such as reflectance confocal microscopy (RCM), optical coherence tomography (OCT), magnetic resonance imaging (MRI), near-infrared (NIR) bioimaging, positron emission tomography (PET), and their combinations provide non-invasive imaging data that may help in the early detection of cutaneous tumors and surgical planning. Hence, they seem appropriate for observing dynamic processes such as blood flow, immune cell activation, and tumor energy metabolism, which may be relevant for disease evolution. This review discusses the latest technological and methodological advances in imaging techniques that may be applied for skin cancer detection and monitoring. In the first instance, we will describe the principle and prospective clinical applications of the most commonly used imaging techniques, highlighting the challenges and opportunities of their implementation in the clinical setting. We will also highlight how imaging techniques may complement the molecular and histological approaches in sharpening the non-invasive skin characterization, laying the ground for more personalized approaches in skin cancer patients.

Predictors of False Negative Sentinel Lymph Node Biopsy in Clinically Localized Merkel Cell Carcinoma

BACKGROUND

Sentinel lymph node biopsy (SLNB) is routinely recommended for clinically localized Merkel cell carcinoma (MCC); however, predictors of false negative (FN) SLNB are undefined.

METHODS

Patients from six centers undergoing wide excision and SLNB for stage I/II MCC (2005-2020) were identified and were classified as having either a true positive (TP), true negative (TN) or FN SLNB. Predictors of FN SLNB were identified and survival outcomes were estimated.

RESULTS

Of 525 patients, 28 (5.4%), 329 (62.7%), and 168 (32%) were classified as FN, TN, and TP, respectively, giving an FN rate of 14.3% and negative predictive value of 92.2% for SLNB. Median follow-up for SLNB-negative patients was 27 months, and median time to nodal recurrence for FN patients was 7 months. Male sex (hazard ratio [HR] 3.15, p = 0.034) and lymphovascular invasion (LVI) (HR 2.22, p = 0.048) significantly correlated with FN, and increasing age trended toward significance (HR 1.04, p = 0.067). The 3-year regional nodal recurrence-free survival for males >75 years with LVI was 78.5% versus 97.4% for females ≤75 years without LVI (p = 0.009). Five-year disease-specific survival (90.9% TN vs. 51.3% FN, p < 0.001) and overall survival (69.9% TN vs. 48.1% FN, p = 0.035) were significantly worse for FN patients.

CONCLUSION

Failure to detect regional nodal microscopic disease by SLNB is associated with worse survival in clinically localized MCC. Males, patients >75 years, and those with LVI may be at increased risk for FN SLNB. Consideration of increased nodal surveillance following negative SLNB in these high-risk patients may aid in early identification of regional nodal recurrences.

The Effects of Modified Lymphoscintigraphy Techniques on Sentinel Lymph Node Biopsy Success During the COVID-19 Pandemic Period

BACKGROUND AND OBJECTIVE

Sampling of the sentinel lymph node (SLN) in breast cancer provides accurate information about the condition of the axilla in 95% of cases. Technically in detecting SLN; radioactive substance, dyers or both are used. During the COVID-19 (Coronavirus disease 2019) pandemic, delayed images were not taken in lymphoscintigraphy to reduce the risk of transmission by shortening the waiting time in our center. In this study, the effects of early and delayed lymphoscintigraphic images and only early images on our clinical practice were evaluated.

METHODS

We investigated the data of 147 patients in this study who underwent SLNB due to early-stage breast cancer at our institute during the COVID-19 pandemic period (PP) (March/April/May 2020) and within 3 months before the pandemic were evaluated.

RESULTS

Patients were divided into two groups, before pandemic (BP) and PP. BP consisted of patients whose early and delayed images were taken in lymphoscintigraphy whereas PP consisted of those with early images only. There were 74 patients in the BP group and 73 patients in the PP group. Early phase increased uptake was not observed in 23 patients, and increased uptake was obtained from 22 of these patients with delayed imaging in BP period. In PP, increased uptake was not observed in 12 patients. SLN was not detected in 2 patients in the BP group and 7 in the PP group. It was found that the sensitivity, NPV and accuracy of the SLNB procedure performed after taking delayed images was higher.

CONCLUSIONS

In the present study, we believe that if technically possible, delayed images taken during the lymphoscintigraphy can assist the surgeon in terms of SLN detection and the number of SLNs removed.

Comparison of 99mTc-Labeled Colloid SPECT/CT and Planar Lymphoscintigraphy in Sentinel Lymph Node Detection in Patients with Melanoma: A Meta-Analysis

We compared the detection rate (DR) for sentinel lymph nodes (SLN), the number of SLNs and the subjects with additional SLNs of single-photon emission computed tomography (SPECT/CT) and planar lymphoscintigraphy (PL) in patients with melanoma. Furthermore, we evaluated the impact of SPECT/CT on surgical plans. Articles containing head-to-head comparisons between SPECT/CT and PL were searched in Pubmed/MEDLINE and Scopus. The literature search was updated until December 31st, 2019. DR was calculated on a per patient-based analysis; the studies were pooled by their odds ratios (ORs) with a random effects model to assess the significance of difference (p < 0.05). The number of additional SLNs (calculated as the relative risk) and pooled proportion of patients with additional SLNs were investigated. The pooled ratio of surgical procedures influenced by the SPECT/CT findings was calculated. Seventeen studies with 1438 patients were eligible for the calculation of DR of SPECT/CT and PL. The average DR was 98.28% (95% confidence interval (95% CI): 97.94-99.19%) for the SPECT/CT and 95.53% (95% CI: 92.55-97.77%) for the PL; OR of 2.31 (95% CI: 1.66-4.18, p < 0.001) in favor of the SPECT/CT. There was a relative risk of a higher number of SLNs (1.13) for the SPECT/CT and 17.87% of patients with additional SLNs were detected by SPECT/CT. The average impact of SPECT/CT on surgery resulted in 37.43% of cases. This meta-analysis favored SPECT/CT over PL for the identification of SLNs in patients with melanoma due to a higher DR, reproducibility, number of SLNs depicted, proportion of patients with additional SLNs and the impact on the surgical plan. However, PL remains a good option due to the high values of the DR for SLNs.

Ultrasound, CT, MRI, or PET-CT for staging and re-staging of adults with cutaneous melanoma

BACKGROUND

Melanoma is one of the most aggressive forms of skin cancer, with the potential to metastasise to other parts of the body via the lymphatic system and the bloodstream. Melanoma accounts for a small percentage of skin cancer cases but is responsible for the majority of skin cancer deaths. Various imaging tests can be used with the aim of detecting metastatic spread of disease following a primary diagnosis of melanoma (primary staging) or on clinical suspicion of disease recurrence (re-staging). Accurate staging is crucial to ensuring that patients are directed to the most appropriate and effective treatment at different points on the clinical pathway. Establishing the comparative accuracy of ultrasound, computed tomography (CT), magnetic resonance imaging (MRI), and positron emission tomography (PET)-CT imaging for detection of nodal or distant metastases, or both, is critical to understanding if, how, and where on the pathway these tests might be used.

OBJECTIVES

Primary objectivesWe estimated accuracy separately according to the point in the clinical pathway at which imaging tests were used. Our objectives were:• to determine the diagnostic accuracy of ultrasound or PET-CT for detection of nodal metastases before sentinel lymph node biopsy in adults with confirmed cutaneous invasive melanoma; and• to determine the diagnostic accuracy of ultrasound, CT, MRI, or PET-CT for whole body imaging in adults with cutaneous invasive melanoma:○ for detection of any metastasis in adults with a primary diagnosis of melanoma (i.e. primary staging at presentation); and○ for detection of any metastasis in adults undergoing staging of recurrence of melanoma (i.e. re-staging prompted by findings on routine follow-up).We undertook separate analyses according to whether accuracy data were reported per patient or per lesion.Secondary objectivesWe sought to determine the diagnostic accuracy of ultrasound, CT, MRI, or PET-CT for whole body imaging (detection of any metastasis) in mixed or not clearly described populations of adults with cutaneous invasive melanoma.For study participants undergoing primary staging or re-staging (for possible recurrence), and for mixed or unclear populations, our objectives were:• to determine the diagnostic accuracy of ultrasound, CT, MRI, or PET-CT for detection of nodal metastases;• to determine the diagnostic accuracy of ultrasound, CT, MRI, or PET-CT for detection of distant metastases; and• to determine the diagnostic accuracy of ultrasound, CT, MRI, or PET-CT for detection of distant metastases according to metastatic site.

SEARCH METHODS

We undertook a comprehensive search of the following databases from inception up to August 2016: Cochrane Central Register of Controlled Trials; MEDLINE; Embase; CINAHL; CPCI; Zetoc; Science Citation Index; US National Institutes of Health Ongoing Trials Register; NIHR Clinical Research Network Portfolio Database; and the World Health Organization International Clinical Trials Registry Platform. We studied reference lists as well as published systematic review articles.

SELECTION CRITERIA

We included studies of any design that evaluated ultrasound (with or without the use of fine needle aspiration cytology (FNAC)), CT, MRI, or PET-CT for staging of cutaneous melanoma in adults, compared with a reference standard of histological confirmation or imaging with clinical follow-up of at least three months' duration. We excluded studies reporting multiple applications of the same test in more than 10% of study participants.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted all data using a standardised data extraction and quality assessment form (based on the Quality Assessment of Diagnostic Accuracy Studies 2 (QUADAS-2)). We estimated accuracy using the bivariate hierarchical method to produce summary sensitivities and specificities with 95% confidence and prediction regions. We undertook analysis of studies allowing direct and indirect comparison between tests. We examined heterogeneity between studies by visually inspecting the forest plots of sensitivity and specificity and summary receiver operating characteristic (ROC) plots. Numbers of identified studies were insufficient to allow formal investigation of potential sources of heterogeneity.

MAIN RESULTS

We included a total of 39 publications reporting on 5204 study participants; 34 studies reporting data per patient included 4980 study participants with 1265 cases of metastatic disease, and seven studies reporting data per lesion included 417 study participants with 1846 potentially metastatic lesions, 1061 of which were confirmed metastases. The risk of bias was low or unclear for all domains apart from participant flow. Concerns regarding applicability of the evidence were high or unclear for almost all domains. Participant selection from mixed or not clearly defined populations and poorly described application and interpretation of index tests were particularly problematic.The accuracy of imaging for detection of regional nodal metastases before sentinel lymph node biopsy (SLNB) was evaluated in 18 studies. In 11 studies (2614 participants; 542 cases), the summary sensitivity of ultrasound alone was 35.4% (95% confidence interval (CI) 17.0% to 59.4%) and specificity was 93.9% (95% CI 86.1% to 97.5%). Combining pre-SLNB ultrasound with FNAC revealed summary sensitivity of 18.0% (95% CI 3.58% to 56.5%) and specificity of 99.8% (95% CI 99.1% to 99.9%) (1164 participants; 259 cases). Four studies demonstrated lower sensitivity (10.2%, 95% CI 4.31% to 22.3%) and specificity (96.5%,95% CI 87.1% to 99.1%) for PET-CT before SLNB (170 participants, 49 cases). When these data are translated to a hypothetical cohort of 1000 people eligible for SLNB, 237 of whom have nodal metastases (median prevalence), the combination of ultrasound with FNAC potentially allows 43 people with nodal metastases to be triaged directly to adjuvant therapy rather than having SLNB first, at a cost of two people with false positive results (who are incorrectly managed). Those with a false negative ultrasound will be identified on subsequent SLNB.Limited test accuracy data were available for whole body imaging via PET-CT for primary staging or re-staging for disease recurrence, and none evaluated MRI. Twenty-four studies evaluated whole body imaging. Six of these studies explored primary staging following a confirmed diagnosis of melanoma (492 participants), three evaluated re-staging of disease following some clinical indication of recurrence (589 participants), and 15 included mixed or not clearly described population groups comprising participants at a number of different points on the clinical pathway and at varying stages of disease (1265 participants). Results for whole body imaging could not be translated to a hypothetical cohort of people due to paucity of data.Most of the studies (6/9) of primary disease or re-staging of disease considered PET-CT, two in comparison to CT alone, and three studies examined the use of ultrasound. No eligible evaluations of MRI in these groups were identified. All studies used histological reference standards combined with follow-up, and two included FNAC for some participants. Observed accuracy for detection of any metastases for PET-CT was higher for re-staging of disease (summary sensitivity from two studies: 92.6%, 95% CI 85.3% to 96.4%; specificity: 89.7%, 95% CI 78.8% to 95.3%; 153 participants; 95 cases) compared to primary staging (sensitivities from individual studies ranged from 30% to 47% and specificities from 73% to 88%), and was more sensitive than CT alone in both population groups, but participant numbers were very small.No conclusions can be drawn regarding routine imaging of the brain via MRI or CT.

AUTHORS' CONCLUSIONS

Review authors found a disappointing lack of evidence on the accuracy of imaging in people with a diagnosis of melanoma at different points on the clinical pathway. Studies were small and often reported data according to the number of lesions rather than the number of study participants. Imaging with ultrasound combined with FNAC before SLNB may identify around one-fifth of those with nodal disease, but confidence intervals are wide and further work is needed to establish cost-effectiveness. Much of the evidence for whole body imaging for primary staging or re-staging of disease is focused on PET-CT, and comparative data with CT or MRI are lacking. Future studies should go beyond diagnostic accuracy and consider the effects of different imaging tests on disease management. The increasing availability of adjuvant therapies for people with melanoma at high risk of disease spread at presentation will have a considerable impact on imaging services, yet evidence for the relative diagnostic accuracy of available tests is limited.

A pilot study of SPECT/CT-based mixed-reality navigation towards the sentinel node in patients with melanoma or Merkel cell carcinoma of a lower extremity

OBJECTIVE

To explore the feasibility of an intraoperative navigation technology based on preoperatively acquired single photon emission computed tomography combined with computed tomography (SPECT/CT) images during sentinel node (SN) biopsy in patients with melanoma or Merkel cell carcinoma.

MATERIALS AND METHODS

Patients with a melanoma (n=4) or Merkel cell carcinoma (n=1) of a lower extremity scheduled for wide re-excision of the primary lesion site and SN biopsy were studied. Following a Tc-nanocolloid injection and lymphoscintigraphy, SPECT/CT images were acquired with a reference target (ReTp) fixed on the leg or the iliac spine. Intraoperatively, a sterile ReTp was placed at the same site to enable SPECT/CT-based mixed-reality navigation of a gamma ray detection probe also containing a reference target (ReTgp).The accuracy of the navigation procedure was determined in the coronal plane (x, y-axis) by measuring the discrepancy between standard gamma probe-based SN localization and mixed-reality-based navigation to the SN. To determine the depth accuracy (z-axis), the depth estimation provided by the navigation system was compared to the skin surface-to-node distance measured in the computed tomography component of the SPECT/CT images.

RESULTS

In four of five patients, it was possible to navigate towards the preoperatively defined SN. The average navigational error was 8.0 mm in the sagittal direction and 8.5 mm in the coronal direction. Intraoperative sterile ReTp positioning and tissue movement during surgery exerted a distinct influence on the accuracy of navigation.

CONCLUSION

Intraoperative navigation during melanoma or Merkel cell carcinoma surgery is feasible and can provide the surgeon with an interactive 3D roadmap towards the SN or SNs in the groin. However, further technical optimization of the modality is required before this technology can become routine practice.

Sentinel Lymph Node Biopsy in Cutaneous Melanoma: Standard and New Technical Procedures and Clinical Advances. A Systematic Review of the Literature

Melanoma is an important public health problem, and its incidence is increasing worldwide. The disease status of regional lymph nodes is the most important prognostic factor in early-stage melanoma patients. Sentinel lymph node biopsy (SLNB) was introduced in the early 1990s as a less invasive procedure than complete lymph node dissection to allow histopathologic evaluation of the "sentinel lymph node" (SLN), which is the first node along the lymphatic pathway from a primary tumor. Sentinel lymph node biopsy has minimal complication risks compared with standard complete lymph node dissection. Currently, SLNB is the accepted method for staging patients with clinically node-negative cutaneous melanoma and provides the most powerful prognostic information by evaluating the nodal basin status. The current practice of SLNB consists of the injection of Tc-labeled radiopharmaceutical, preoperative lymphoscintigraphy with the possibility of using the SPECT/CT hybrid imaging, and intraoperative SLN localization using a handheld gamma probe with or without the use of blue dye. Recently, the SLN localization and detection have been enhanced with the use of new tracers and new intraoperative devices, which have demonstrated to be particularly useful in melanomas of the head and neck region and in area of complex anatomy. Despite these important advances in the technology and the increasing experience in SLN mapping, major research centers have reported a false-negative rate higher than 15%. This relatively high false-negative rate, greater than those reported in the initial validation studies, points out the importance for the nuclear medicine community to continuously improve their knowledge on the biological behavior of melanoma and to improve the technical aspects that may allow more precise staging. For the SLNB procedure to be accurate, it is of critical importance that all "true" SLNs are identified and removed for examination. The aim of this article is to provide general information about the SLNB procedure in clinical practice highlighting the importance of standardization and accuracy of SLN identification in the light of the most recent technical innovations.

Utility of hybrid SPECT/CT in primary melanoma lymphoscintigraphy: A retrospective case series

INTRODUCTION

Sentinel lymph node (SLN) biopsy is widely accepted as an important part of staging cutaneous malignant melanoma. Hybrid single photon emission computed tomography and computed tomography (SPECT/CT) may identify additional SLN and provide important information to the surgeon performing SLN biopsy. We report our experience at a major referral centre for melanoma surgery.

METHODS

Retrospective case series of pre-operative sentinel node lymphoscintigraphy for primary melanoma over a consecutive 12-month period. All patients had planar imaging and hybrid SPECT/CT.

RESULTS

At least 1 SLN was successfully identified in 82 of 86 eligible patients (95.3%). These 82 patients had 144 SLNs (mean 1.8). There were no patients where the SLN was seen only with SPECT/CT. Additional information was provided by SPECT/CT in 32 patients (39.0%). Histology reports were available for 52 patients, 9 (17.3%) had at least 1 SLN positive for metastatic disease.

CONCLUSIONS

We achieved a high rate of SLN identification. SPECT/CT was most frequently helpful when the primary melanoma was located in the head, neck and trunk. Routine use of SPECT/CT during lymphoscintigraphy provides important anatomical information and may reduce the false-negative rate.

SPECT/CT Improves Detection of Metastatic Sentinel Lymph Nodes in Patients with Head and Neck Melanoma

BACKGROUND

A positive sentinel lymph node (SLN) is the most important prognostic factor for predicting survival in cutaneous melanoma. This study aimed to evaluate how the addition of single-photon emission computed tomography (SPECT) and computed tomography (CT) to planar lymphoscintigraphy (PL) alters SLN identification, yield, and localization of metastatic nodes in head and neck melanoma.

METHODS

This retrospective review examined patients undergoing SLN biopsy for cutaneous melanoma of the head and neck between July 2003 and December 2015. Patient demographics and pathologic outcomes were compared for patients undergoing SPECT-CT versus PL. A multivariable logistic regression analysis was used to identify factors associated with the identification of a positive SLN.

RESULTS

Among 176 patients undergoing SLN biopsy, 91 underwent PL and 85 underwent SPECT-CT and PL. The patients in the SPECT-CT group were older than the PL patients (p = 0.050) but the groups did not differ in gender (p = 0.447), Breslow thickness (p = 0.744), or total number of SLNs identified (p = 0.633). As shown by the multivariate regression analysis, only Breslow thickness [odds ratio (OR) 1.47; 95 % confidence interval (CI) 1.17-1.84] and SPECT-CT (OR 3.58; 95 % CI 1.24-10.4) were associated with a positive SLN.

CONCLUSION

The use of SPECT-CT for patients with head and neck cutaneous melanoma significantly increases the likelihood of retrieving a positive SLN. Long-term follow-up evaluation is needed for further definition of the impact that SPECT-CT has on recurrence and survival.

Sentinel Node Mapping in Melanoma of the Back: SPECT/CT Helps Discriminate "True" and "False" in-Transit Lymph Nodes

A 32-year-old man with melanoma on the right paramedian region of the lower back underwent lymphoscintigraphy for radioguided sentinel node (SN) biopsy. Planar imaging showed the presence of 2 sites of radioactivity accumulation corresponding to an axillary SN and to an "in-transit" SN, located on the right side of the upper trunk. A further "hot spot" placed on the left paramedian region of the lower back was identified by planar lymphoscintigraphy. This last finding could be mistaken for another "in-transit" SN, but SPECT/CT demonstrated it was actually a nonspecific radiopharmaceutical accumulation at the level of the right renal pelvis.

Clinical Usefulness of a Novel Freehand 3D Imaging Device for Radio-Guided Intraoperative Sentinel Lymph Node Detection in Malignant Melanoma

INTRODUCTION

Patients with invasive malignant melanoma are commonly referred for sentinel lymph node (SLN) detection. A recently proposed 3D tomographic imaging modality is freehand SPECT (declipseSPECT). This "bedside system" was originally developed to enable minimal-invasive image-guided surgery. The aim of this retrospective analysis was to assess the clinical use of this freehand detector device for image-guided lymphatic mapping in melanoma patients.

MATERIALS AND METHODS

Thirty-nine patients (12 female and 27 male subjects) were included (age, 30-79 years). All of them had at least one location of melanoma with tumoral stage pT1b or greater in 37 and pTx in 2 patients in different sites of the body (abdomen in 4, back in 14, head and neck in 5, lower extremity in 6, and upper extremity in 10 patients). Lymphoscintigraphy was performed with 65 to 127 MBq Tc-nanocolloid. A 2-day protocol was applied with SPECT-CT acquisition (Brightview XCT, Philips) at day 1 and surgery using radio-guided freehand SPECT at day 2. SPECT-CT data were integrated into the 3D navigation system to enable fast and direct localization of the SLN by displaying the depth of the node from the skin surface and lateral margins in relation to the gamma probe.

RESULTS

Comparable preoperative imaging and intraoperative localization was observed in 18 patients. In 14 cases, more lymph nodes were resected than detected by SPECT-CT including 1 patient without evidence of an SLN because this node was located close to the primary right ear tumor. In 10 of these patients, intraoperative freehand SPECT revealed additional sites of lymph nodes. In 7 cases, more findings were detected by SPECT-CT than surgically removed. The procedure was safe and easy to perform, and the time of surgical intervention using freehand SPECT was in the range of 36 to 133 minutes (mean time, 66.56 minutes).

CONCLUSIONS

Freehand SPECT detected more SLN compared with SPECT-CT, and the tracking system provided precise anatomical localization of the radioactive-labeled SLNs.

Role of SPECT-CT in sentinel lymph node biopsy in patients diagnosed with head and neck melanoma

OBJECTIVE

Assess the role of SPECT-CT in sentinel lymph node (SLN) biopsy in the accurate anatomical location of the SNL in patients with cutaneous head and neck melanoma.

MATERIAL AND METHODS

A retrospective study was conducted from February 2010 to June 2013 on 22 consecutive patients with a diagnosis of cutaneous head and neck melanoma (9 female, 13 male), with a mean age of 55 years old and who met the inclusion criteria for SLN biopsy. Patients underwent preoperative scanning after peri-scar injection of (99m)Tc-labeled-nanocolloid. Planar images of the injection-site, whole-body, and SPECT-CT scanning were acquired.

RESULTS

Detection rate of SLN reached up to 91% (20/22 patients) by planar lymphoscintigraphy and 95.4% (21/22 patients) by SPECT-CT. SPECT-CT provided an accurate location of SLN in 14/22 patients, enabling to improve the surgical approach (clinical impact: 63.6%). SLN was positive for metastatic cells in 9.1% patients.

CONCLUSION

SPECT-CT provides detailed anatomical SLN location and allows detecting a higher number of SLN than planar lymphoscintigraphy. Routine use of SPECT-CT is recommended in order to optimise the SLN detection and location in patients with head and neck melanoma.

Techniques that accurately identify the sentinel lymph node in cancer

Sentinel lymph node (SLN) biopsy has become the gold standard for patients with melanoma and breast cancer but it’s clinical application in other solid tumor types such as cancers of the esophagus, stomach, colon and rectum, head and neck, penis, uterine cervix and endometrium has been somewhat limited. Commonly used mapping techniques utilizing the combination of radiocolloid and blue dye may result in reduced SLN detection and increased false negative rates when applied to cancers with more complex lymphatic drainage patterns. Novel localization techniques including near infrared fluorescence, high resolution imaging and molecular targeted agents have been developed to address the limitations of conventional SLN detection practices in many solid tumor types. This article reviews the indications, techniques and detection rates for SLN biopsy in several different solid tumor types as well as the promising novel techniques created to address the contemporary limitations of this procedure.

Cost-effectiveness of preoperative SPECT/CT combined with lymphoscintigraphy vs. lymphoscintigraphy for sentinel lymph node excision in patients with cutaneous malignant melanoma

PURPOSE

Malignant melanoma has become a major growing interdisciplinary problem in public health worldwide. Sentinel lymph node excision (SLNE) in conjunction with preoperative SPECT/CT is considered the most sensitive and specific staging test for the detection of micrometastatic melanoma in regional lymph nodes. Among patients with clinically lymph node-negative melanoma, the use of SPECT/CT-aided SLNE compared with SLNE alone has been found to be associated with a higher frequency of metastatic involvement and a higher rate of disease-free survival. The aim of this study was to analyse the cost-effectiveness of SLNE with preoperative SPECT/CT for detecting sentinel lymph nodes versus that of standard SLNE with preoperative lymphoscintigraphy from a single-institution database.

METHODS

Cost-effectiveness analysis of two surgical approaches for SLNE for malignant melanoma at the University Hospital Essen, Skin Cancer Center in Essen, Germany. Between March 2003 and April 2011 464 patients eligible for SLNE were identified . Of these patients, 403 with clinically negative lymph nodes who underwent SLNE with or without preoperative SPECT/CT qualified for subsequent analysis.

RESULTS

Between March 2003 and October 2008, 254 patients were operated upon with the standard technique. From November 2008, 149 patients underwent the SPECT/CT technique. Cost analysis showed a mean cost saving of 710.50 when SPECT/CT was added to preoperative imaging. This was achieved by a reduction in operative time (median, Q1;Q3, 40 min, 40;50 min, vs. 45 min, 35;60 min; p = 0.002), hospital stay duration (5 days, 3;8 days, vs. 8 days, 4.5;14.5 days; p < 0.001) and more frequent use of local anaesthesia (90.6 % vs. 70.5 %; p < 0.001). The median cost of SLNE using SPECT/CT was 1,619.7 (Q1;Q3 1,317.0;2,603.4) and of SLNE without SPECT/CT was 2,330.2 ( 1,468.3;4,058.1; p < 0.001), a cost saving of 30.5 %.

CONCLUSION

In patients with cutaneous melanoma, the use of preoperative SPECT/CT-aided SLNE compared with standard SLNE was associated not only with higher detection of metastatic involvement but also with a significant cost reduction.

Sentinel lymph node mapping in melanoma: the issue of false-negative findings

Management of cutaneous melanoma has changed after introduction in the clinical routine of sentinel lymph node biopsy (SLNB) for nodal staging. By defining the nodal basin status, SLNB provides a powerful prognostic information. Nevertheless, some debate still surrounds the accuracy of this procedure in terms of false-negative rate. Several large-scale studies have reported a relatively high false-negative rate (5.6%-21%), correctly defined as the proportion of false-negative results with respect to the total number of "actual" positive lymph nodes. In this review, we identified all the technical aspects that the nuclear medicine physician, the surgeon, and the pathologist should take into account to improve accuracy of the procedure and minimize the false-negative rate. In particular, SPECT/CT imaging detects more SLNs than those found by planar lymphoscintigraphy. Furthermore, the nuclear medicine community should reach a consensus on the radioactive counting rate threshold to better guide the surgeon in identifying the lymph nodes with the highest likelihood of housing metastases ("true biologic SLNs"). Analysis of the harvested SLNs by conventional techniques is also a further potential source for error. More accurate SLN analysis (eg, molecular analysis by reverse transcriptase-polymerase chain reaction) and more extensive SLN sampling identify more positive nodes, thus reducing the false-negative rate.The clinical factors identifying patients at higher-risk local recurrence after a negative SLNB include older age at diagnosis, deeper lesions, histological ulceration, and head-neck anatomic location of the primary lesion.The clinical impact of a false-negative SLNB on the prognosis of melanoma patients remains controversial, because the majority of studies have failed to demonstrate overall statistically significant disadvantage in melanoma-specific survival for false-negative SLNB patients compared with true-positive SLNB patients.When new more effective drugs will be available in the adjuvant setting for stage III melanoma patients, the implication of an accurate staging procedure for the sentinel lymph nodes will be crucial for both patients and clinicians. Standardization and accuracy of SLN identification, removal, and analysis are required.

Extraordinary Lymph Drainage in Cutaneous Malignant Melanoma and the Value of Hybrid Imaging: A Case Report

In melanoma patients, preoperative lymphoscintigraphy has become a gold standard. The role of single-photon emission computed tomography (SPECT) or its combination with computed tomography (SPECT-CT) as part of the standard sentinel scintigraphy protocol has yet to be determined. A 46-year-old female patient with melanoma of the trunk received preoperative lymphoscintigraphy and subsequent surgical excision. Planar imaging displayed two hot spots in the region of the primary lesion. No other lymphatic flow pathways could be appreciated. Two focal hot spots, one dorsal to the primary lesion near the left latissimus dorsi muscle and one just lateral to the primary lesion in the subcutaneous tissue, were appreciated with SPECT-CT imaging. The primary melanoma lesion, as well as the two additional lesions, which were detected by SPECT-CT, were excised and sent for histopathological examination. While the primary lesion was a superficial spreading melanoma, the lesions appreciated in SPECT-CT revealed four sentinel lymph nodes, each of which was negative for tumor cells. Melanomas, especially of the trunk, can demonstrate multiple lymphatic drain basins in a large percentage of patients. Given that without the detailed anatomical information provided by SPECT-CT it would be very difficult to locate the diverse lymphatic drain basins and their lymph nodes, we would suggest routinely implementing SPECT-CT in the standard planar sentinel imaging protocol.

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.

[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.

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.

The role of hybrid SPECT/CT for lymphatic mapping in patients with melanoma

INTRODUCTION

Lymphoscintigraphy in melanoma provides important information on the dynamic drainage of the primary tumour and the location of the sentinel lymph node (SLN). Unfortunately these images lack anatomical detail. Single positron emission computed tomography/computed tomography (SPECT/CT) provides extremely detailed information on the location of the SLN and its relationship with surrounding structures and it is the aim of this study to report our initial experience with this technology.

METHODS

Thirty-two patients undergoing sentinel lymph node biopsy (SLNB) at our unit between October 2010 and October 2011 were included in this study. In each case, conventional planar lymphoscintigraphy (PL) was followed by SPECT/CT. Images of each patient were reviewed by the operating consultant plastic surgeon and a consultant radiologist. A joint opinion was issued on the number of lymph nodes identified by each imaging modality and whether SPECT/CT influenced surgical approach.

RESULTS

Both PL and SPECT/CT detected the SLN in 31/32 patients. There was no significant difference between the number of SLN identified by PL and SPECT (p = 0.69). In relation to the true number of SLNs identified intra-operatively by gamma probing and blue dye, there was no statistically significant difference in accuracy between SPECT/CT and PL (p = 0.50). SPECT/CT was judged to provide useful anatomical information in all cases. Surgical approach was altered in 12/32 patients and contributed to the detection of SLNs that were positive for metastases.

CONCLUSIONS

In relation to true SLN number, SPECT/CT was not significantly more accurate than PL. The detailed anatomical information provided by SPECT/CT improved confidence and pre-operative planning in all patients. In select cases, particularly in the head and neck, SPECT/CT overcame the limitations of PL and facilitated the detection and sampling of metastatic nodes.

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.

Lymphatic drainage patterns from melanomas on the shoulder or upper trunk to cervical lymph nodes and implications for the extent of neck dissection

Purpose

To determine the incidence and pattern of cervical lymphatic drainage in patients with melanomas located on the upper limb or trunk, and to evaluate our current neck dissection protocol for those patients with a N+ neck.

Methods

Of 1192 melanoma patients who underwent sentinel node biopsy, 631 were selected with a primary tumor on the upper limb or trunk. All lymphoscintigrams, SPECT/CT images and operative reports were reviewed to determine the exact locations of sentinel nodes visualized preoperatively and dissected during operation.

Results

Thirty-nine (6.2 %) of 631 patients with a melanoma on the upper limb or trunk showing cervical lymph node drainage were identified. In 34 (87 %) of 39 patients, sentinel nodes were excised from level IV or Vb, and in 30 of those 39 patients simultaneous from the axilla. In the remaining five patients (13 %), sentinel nodes were collected from level IIb, level III or the suboccipital region. All collected sentinel nodes were located in the intended dissection area for N+ patients. Thirteen patients (33 %) had a total of 22 tumor-positive sentinel nodes in either the axilla (n = 10), level IV (n = 2), Vb (n = 9) or suboccipital (n = 1).

Conclusions

Only a minority of the patients with upper limb or trunk melanomas demonstrated lymphatic drainage to cervical lymph node basins, with preferential drainage to levels IV and Vb. Our current dissection protocol of levels II–V, with or without extension to the suboccipital region, in those patients with involved cervical sentinel nodes seems sufficient.

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.

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.

The diagnostic value of adding dynamic scintigraphy to standard delayed planar imaging for sentinel node identification in melanoma patients

PURPOSE

The aim of this study was to compare early dynamic imaging combined with delayed static imaging and single photon emission computed tomography (SPECT)/CT with delayed, planar, static imaging alone for sentinel node (SN) identification in melanoma patients.

METHODS

Three hundred and seven consecutive melanoma patients referred for SN biopsy (SNB) were examined using combined imaging. Secondary interpretation of only the delayed static images was subsequently performed. In 220 patients (72%), complete surgical and pathological information relating to the SNB was available. The number of SNs identified and number of patients with positive SNs were compared between the two interpretations of the imaging studies and, when available, related to pathology data.

RESULTS

A slightly higher number of SNs (mean 0.12/patient) was identified when interpreting only delayed static images compared to combined imaging. In a direct patient-to-patient comparison, the number of SN(s) identified on the combined vs static images only showed moderate agreement (kappa value 0.56). In 38 patients (17%), positive SNs were identified by the combined procedure compared to 35 (16%) by static imaging only. Thus by static imaging only, tumour-positive SNs were not identified in 3 of 38 patients (8%).

CONCLUSION

For SN identification in melanoma patients, dynamic imaging combined with delayed static imaging and SPECT/CT is superior to delayed static imaging only because the latter is more likely to fail to identify SNs containing metastases.