Results of a Prospective Multicenter International Atomic Energy Agency Sentinel Node Trial on the Value of SPECT/CT Over Planar Imaging in Various Malignancies

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.

Update on Sentinel Lymph Node Methods and Pathology in Breast Cancer

Breast cancer stands out as the most commonly diagnosed cancer among women globally. Precise lymph node staging holds critical significance for both predicting outcomes in early-stage disease and formulating effective treatment strategies to control regional disease progression in breast cancer patients. No imaging technique possesses sufficient accuracy to identify lymph node metastases in the early stages (I or II) of primary breast cancer. However, the sentinel node procedure emerges as a valuable approach for identifying metastatic axillary nodes. The sentinel lymph node is the hypothetical first lymph node or group of nodes draining a cancer. In case of established cancerous dissemination, it is postulated that the sentinel lymph nodes are the target organs primarily reached by metastasizing cancer cells from the tumor. The utilization of the sentinel node technique has brought about changes in the assessment of lymph nodes. It involves evaluating the sentinel node during surgery, enabling prompt lymph node dissection when the sentinel node procedure is positive. Additionally, histological ultra-stratification is employed to uncover occult metastases. This review aims to provide an update of this valuable technique, with focus on the practical aspects of the procedure and the different histological protocols of sentinel node evaluation in breast cancer.

New EAU/ASCO guideline recommendations on sentinel node biopsy for penile cancer and remaining challenges from a nuclear medicine perspective

INTRODUCTION

The European Association of Urology (EAU) and the American Society of Clinical Oncology (ASCO) recently issued updated guidelines on penile cancer, emphasising dynamic sentinel node biopsy (DSNB) as the preferred method for surgical staging among patients with invasive penile tumours and no palpable inguinal lymphadenopathy. This paper outlines the rationale behind this new recommendation and describes remaining challenges, as well as strategies for promoting DSNB worldwide.

MAIN TEXT

DSNB offers high diagnostic accuracy with the lowest postoperative complications compared to open or minimally invasive inguinal lymph node dissection (ILND), prompting its preference in the new guidelines. Nevertheless, despite its advantages, there are challenges hampering the widespread adoption of DSNB. This includes the false-negative rate associated with DSNB and the potential negative impact on patient outcome. To address this issue, improvements should be made in several areas, including refining the timing and interpretation of the lymphoscintigraphy and the single photon emission computed tomography/computed tomography images. In addition, the quantity of tracer employed and choice of the injection site for the radiopharmaceutical should be optimised. Finally, limiting the removal of nodes without tracer activity during surgery may help minimise complication rates.

CONCLUSION

Over the years, DSNB has evolved significantly, related to the dedicated efforts and innovations in nuclear medicine and subsequent clinical studies validating its efficacy. It is now strongly recommended for surgical staging among selected penile cancer patients. To optimise DSNB further, multidisciplinary collaborative research is required to improve SN identification for better diagnostic accuracy and fewer complications.

Nano-tracers for sentinel lymph node detection: current trends in technique and application

Sentinel lymph node (SLN) detection and biopsy is a critical staging component for several cancers. Apart from established methods using dyes or radiolabeled colloids, newer techniques are emerging, like near-infrared fluorescent compounds, targeted molecular radiopharmaceuticals and magnetic nano-tracers. In the overview section of this review, we categorize SLN detection tracers based on their principle of use. We discuss the merits of existing tracers and provide a glimpse of in-development formulations. A subsequent clinical section explores the expanded role of SLN detection in management of various cancers, citing current medical guidelines and the leading conclusions of long-term clinical trials. The concluding section tries to provide a perspective of promising developments and the work required to bring them to clinical fruition.

Continuous innovation in precision radio-guided surgery

Since its origins, nuclear medicine has faced technological changes that led to modifying operating modes and adapting protocols. In the field of radioguided surgery, the incorporation of preoperative scintigraphic imaging and intraoperative detection with the gamma probe provided a definitive boost to sentinel lymph node biopsy to become a standard procedure for melanoma and breast cancer. The various technological innovations and consequent adaptation of protocols come together in the coexistence of the disruptive and the gradual. As obvious examples we have the introduction of SPECT/CT in the preoperative field and Drop-in probes in the intraoperative field. Other innovative aspects with possible application in radio-guided surgery are based on the application of artificial intelligence, navigation and telecare.

Setting-up a training programme for intraoperative molecular imaging and sentinel node mapping: how to teach? How to learn?

BACKGROUND

The current expansion of image-guided surgery is closely related to the role played by radio-guided surgery in supporting the sentinel node (SN) procedure during more than three decades. The so-called triple approach (lymphoscintigraphy, gamma probe detection and blue dye) was not only essential in the seminal validation of the SN procedure but also a first collective learning effort based on skill transfer and outcome-related evaluation which laid the fundaments to delineate the field of intraoperative molecular imaging (IMI) based on a similar multimodality approach and multidisciplinary practice.

METHODS

These elements are also becoming valid in the current incorporation of SPECT/CT and PET/CT to existing and new protocols of IMI procedures and SN mapping concerning other clinical applications. On the other hand, there is a growing tendency to combine novel modern technologies in an allied role with gamma guidance in the operating room following the development of hybrid tracers and multimodal detection approaches. Against this background, learning initiatives are required for professionals working in this area.

RESULTS

This objective has led to a group of European practitioners with large experience in SN mapping and IMI applications to give shape to a programme made up out of specific learning modules aimed to be used as a conductive thread in peripherical or centralised training instances concerning the topic.

CONCLUSION

The presented work, written as a tutorial review, is placed in an available prior-art context and is primarily aimed at medical and paramedical practitioners as well as at hardware and software developers.

Nuclear medicine contribution to precision surgery in breast cancer

Nuclear medicine has significantly contributed to precision surgery in breast cancer in the past decades. Radioguided surgery (RGS) has enabled sentinel node (SN) biopsy in assessing regional nodal involvement modifying the management of patients with early breast cancer. For the axilla the SN procedure has resulted in fewer complications and better quality of life when compared with axillary lymph node dissection. Originally, SN biopsy principally concerned cT 1-2 tumours without evidence of axillary lymph node metastases. However, in last years SN biopsy is also being offered to patients with large or multifocal tumours, ductal carcinoma in situ, ipsilateral breast cancer relapse, and to patients receiving neoadjuvant systemic treatment (NST) for breast sparing surgery. Parallel to this evolution various scientific associations are trying to homogenise issues such as radiotracer choice, breast injection site, preoperative imaging standardisation and SN biopsy timing in relation to NST as well as management of non-axillary SN metastasis (e.g. internal mammary chain). Additionally, RGS is currently used to accomplish primary breast tumour excision either by intralesional radiocolloid injection or by radioactive iodine seed implantation which is also employed to target metastatic axillary lymph nodes. This latter procedure contributes to manage the node-positive axilla in combination with 18F-FDG PET/CT in an effort to tailor systemic and loco regional treatment.

Accuracy of dynamic sentinel lymph node biopsy for inguinal lymph node staging in cN0 penile cancer

BACKGROUND

Penile cancer is characterized by an early lymphatic dissemination. In intermediate and high-risk primary tumors without palpable inguinal lymph nodes, there is a 6-30% risk of micro-metastatic disease. Invasive lymph node staging in these patients is performed using dynamic sentinel lymph node biopsy (DSNB). In this study, the role of DSNB in cN0 penile cancer was studied, evaluating features of sentinel lymph node (SN) visualization and outcome parameters. Patients with penile cancer without inguinal lymph node metastases who were referred for DSNB at our center between January 2015 and May 2021 and had a follow-up period of at least 18 months, were retrospectively included. After injection of 85 ± 20 MBq [^99mTc]Tc-nanocolloid peritumorally, dynamic, static planar and SPECT/CT imaging was performed. Primary endpoints were sensitivity of the diagnostic procedure, disease-free survival and DSNB-related adverse events. Secondary endpoints were SN detection rate, number of SNs and the number of counts of the most active SN.

RESULTS

Seventy-seven penile DSNB procedures in 75 patients (67 ± 11 years) were included. The detection rate of DSNB was 91% and 96% per procedure and groin, respectively. Sensitivity, specificity, negative predictive value (NPV) and positive predictive value (PPV) were 79%, 100%, 97% and 100%, respectively. More SNs were seen on SPECT/CT than on static planar imaging (1.33 vs. 1.17, p = 0.001). The mean counts per SN on static planar imaging was lower compared to SPECT/CT (1343 vs. 5008; p < 0.0001). There was a positive correlation between the total counts of the SN on the static planar image and the SPECT/CT (r = 0.79, p < 0.0001). Only one out of seventy-five patients (1%) experienced DSNB-related adverse events. After 18 months, 58 patients remained disease free (77%), 13 developed local recurrence (17%), and 4 developed lymphatic or distant metastases (5%).

CONCLUSION

DNSB is a safe diagnostic procedure with a good detection rate and in particular high negative predictive value. It can therefore prevent overtreatment of patients with negative inguinal groins on clinical examination and DSNB examination. Finally, DSNB enables an early detection of occult metastases which would not be visualized with standardized imaging modalities.

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.

The impact of sentinel lymph node mapping with hybrid single photon emission computed tomography/computed tomography in patients with melanoma. Comparison to planar radioisotopic lymphoscintigraphy

We studied the diagnostic value of 16 slices of single photon emission computed tomography (SPECT)/computed tomography (CT) in the anatomical localization, image interpretation and extra-sentinel lymph nodes (SLNs) detection compared to dynamic and static planar radioisotopic lymphoscintigraphy (PLS) in patients with melanoma. Eighty-two patients with melanoma underwent dynamic PLS, static PLS and SPECT/CT. Data were obtained using a dual head SPECT/CT 16 slices γ-camera. We evaluated the number and localization of SLNs detected with each imaging method. SPECT/CT demonstrated 48 additional SLNs in comparison with PLS in 29 patients. In five truncal and seven head-neck lesions, dynamic and static PLS failed to detect the SLNs found on SPECT/CT (false negative). In one case of truncal and one case of lower limb melanoma, the foci of increased activity interpreted on PLS as possible SLNs were confirmed to be non-nodal sites of uptake on SPECT/CT (false positive). PLS underestimated the number of SLNs detected, whereas SPECT/CT revealed higher agreement compared to the respective number from histological reports. SPECT/CT showed a better prediction of the number of SLNs and higher diagnostic parameters in comparison to planar imaging. SPECT/CT is an important complementary diagnostic modality to PLS, that improves detection, preoperative evaluation, anatomical landmarks of SLNs and surgical management of patients with melanoma.

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.

Surgical Management of Melanoma: Advances and Updates

PURPOSE OF REVIEW

To review and update surgeons about the evolving complexities in the surgical management of melanoma including lymph node staging and treatment.

RECENT FINDINGS

Primary resection with adequate margins continues to be the standard of care for localized cutaneous melanoma. Sentinel lymph node biopsy is confirmed to be a powerful tool due to its prognostic value and informative guidance for adjuvant treatments and surveillance. Due to the lack of benefit in melanoma-specific survival and distant metastasis-free survival, completion lymph node dissection is not performed routinely after a positive sentinel lymph node biopsy. Neoadjuvant systemic treatment approaches for advanced loco-regional disease show promise in phase I and II clinical trial data, and phase III studies. The surgical management of cutaneous melanoma continues to evolve with further de-escalation of the extent of excision of primary melanomas and the management of lymph node disease.

99mTc-labeled colloid SPECT/CT versus planar lymphoscintigraphy for sentinel lymph node detection in patients with breast cancer: a meta-analysis

Background

The aim of this meta-analysis was to compare single-photon emission computed tomography (SPECT/CT) and planar lymphoscintigraphy (PL) in patients with primary breast cancer, undergoing lymphoscintigraphy at initial staging. Specifically, we assessed the detection rate (DR) for sentinel lymph node (SLN), the absolute number of detected SLNs by each technique, and the proportion of patients with additional SLNs detected by one technique compared to the other one. Finally, we aimed to evaluate the impact of SPECT/CT on the surgical approach.

Methods

Original articles, providing a head-to-head comparison between SPECT/CT and PL, including patients with primary breast cancer at first presentation, were searched in PubMed/MEDLINE and Scopus databases through March 31st, 2022. The DR of the imaging techniques was calculated on a per-patient analysis; studies were pooled on their odds ratios (ORs) with a random-effects model to assess the presence of a significant difference between the DRs of SPECT/CT and PL. The number of additional SLNs, calculated as relative risk (RR), and the pooled proportion of patients with additional SLNs using one imaging technique rather than the other one were investigated. The pooled ratio of surgical procedures (SLN harvesting) influenced by the use of SPECT/CT, according to the surgeons, was calculated.

Results

Sixteen studies with 2693 patients were eligible for the calculation of the DR of SPECT/CT and PL. The DR was 92.11% [95% confidence interval (95% CI) 89.32–94.50%] for SPECT/CT, and 85.12% (95% CI 80.58–89.15%) for PL, with an OR of 1.96 (95% CI 1.51–2.55) in favor of SPECT/CT. There was a relative risk of detection of larger number of SLNs (RR: 1.22, 95% CI 1.14–1.32; 12 studies; 979 patients) for SPECT/CT (n = 3983) compared to PL (n = 3321) and a significant proportion of patients with additional SLNs detected by SPECT/CT, which were missed by PL (18.88%, 95% CI: 11.72%-27.27%; 13 studies). Four articles, with a total number of 1427 patients, revealed that 23.98% of the surgical procedures benefited from the use of SPECT/CT.

Conclusions

This meta-analysis favors SPECT/CT over PL for the identification of SLN in patients with primary breast cancer at staging due to higher DR, more SLNs depicted, and a significant proportion of subjects with additional detected SLNs by SPECT/CT compared to PL. Furthermore, SPECT/CT positively influences the surgical procedure. However, PL remains a satisfactory imaging option for imaging departments not equipped with SPECT/CT due to its good patient-based DR.

Advanced diagnostic imaging of sentinel lymph node in early stage breast cancer

Sentinel lymph node biopsy has been regarded as the standard procedure for early staging breast cancer. One of the key steps is to locate the sentinel lymph node (SLN). The recommended method is the joint use of blue dye and radioisotope. However, due to radionuclide radiation and high cost, it is urgent to develop more convenient and sensitive imaging methods to accurately locate SLN. This article discusses the advancement of accurately locating SLN by isotope tracer imaging, magnetic tracer method, computed tomographic lymphography, and trans-lymphatic contrast-enhanced ultrasound, as well as proposing new propose for clinical diagnosis.

Sentinel Lymph Node Methods in Breast Cancer

Breast cancer is the most frequent cancer diagnosed in women worldwide. Accurate lymph node staging is essential for both prognosis (of early-stage disease) and treatment (for regional control of disease) in patients with breast cancer. The sentinel lymph nodes are the regional nodes that directly drain lymph from the primary tumor. No imaging modality is accurate enough to detect lymph node metastases when a primary breast cancer is at an early stage (I or II), but sentinel lymph node biopsy is a highly reliable method for screening axillary nodes and for identifying metastatic (including micro-metastatic) disease in regional lymph nodes. Despite the widespread use of sentinel lymph node biopsy for early-stage breast cancer, relevant variations have been described regarding practical aspects of the procedure, and some variability has initially been reported regarding the rates of intraoperative sentinel lymph node identification and of false-negative findings, most likely because of differences in the size of the populations being investigated and in lymphatic mapping techniques. Nevertheless, using adequate learning curves and once a multidisciplinary team is experienced with the procedure, improved levels of accuracy are achieved.

Early Institutional Experience of Dual Tracer and Single-Photon Emission Computed-Tomography/Computed-Tomography Mapping for Sentinel Node Biopsy: A Report of Two Early-Stage Breast Cancer

Intraoperative sentinel lymph node mapping (SLNM) with methylene blue dye (MBD) tracer has been the recommended method to detect SLN in early-stage breast cancer patients in low-resource settings. However, the use of MBD alone is hampered by the high false-negative rate; thus, it requires coupling with other mapping methods if the appropriate infrastructure and services are available. In this article, we present two prospective cases detailing our initial experience using the gold-standard dual tracer technique (DTT: MBD and 99mTc-nanocolloid radioisotope) in combination with hybrid single-photon emission computed-tomography/computed-tomography (SPECT/CT) preoperative mapping for image-guided SLN biopsy (SLNB). Overall, both studies were successful in identifying the SLNs, which aided in mapping the possible anatomical spread of the disease.

Effectiveness of SPECT/CT Imaging for Sentinel Node Biopsy Staging of Primary Cutaneous Melanoma and Patient Outcomes

Purpose

Coregistered SPECT/CT can improve accuracy of sentinel node biopsy (SNB) for staging melanoma. This benefit has implications for pathology services and surgical practice with increased diagnostic and surgical workload. The purpose of this study was to investigate the effectiveness of SPECT/CT imaging.

Methods

SNB data were collected over a 10-year period. Preoperative SLN mapping was performed by using planar lymphoscintigraphy (LSG) for all patients (n = 1522) and after October 2015, patients underwent a second co-registered SPECT/CT scan (n = 559). The patients were stratified according to the imaging protocol. The number of nodes and nodal basins were assessed. The reasons for cancellation also were assessed.

Results

A total of 95% (1446/1522) of patients underwent a successful SNB procedure. Significantly more sentinel nodes were identified by the SPECT/CT protocol (3 vs. 2; p < 0.0001). More patients were cancelled in the SPECT/CT cohort (9.3% vs. 2.5%; p < 0.0001). Head & neck, lower limb, and AJCC IB primaries were significantly less likely to proceed to SNB. SPECT/CT identified significantly more positive SNBs (20.9% vs. 16.5%; p = 0.038). SPECT/CT imaging was associated with improved disease-free (hazard ratio [HR] = 0.74; 95% confidence interval [CI]: 0.54–1.0); p = 0.048) and disease-specific survival (HR = 0.48; 95% CI: 0.3–0.78; p = 0.003). Patients who did not proceed to SNB had a significantly increased nodal relapse rate (23.5% vs. 6.8%; HR = 3.4; 95% CI: 1.9–6.2; p < 0.0001) compared with those who underwent SNB.

Conclusions

This large cohort study confirms the increased accuracy of SPECT/CT for identifying SLN metastases, which would appear to have a significant therapeutic benefit, although an increased risk of cancellation of the SNB procedure on the day of surgery.

Utility of indocyanine green as a single tracer for sentinel node biopsy in endometrial cancer

AIM

Our study aims to investigate the safety and effectiveness of sentinel lymph node biopsy using indocyanine green (ICG) for the surgical staging of early-stage endometrial cancer in comparison to technetium-99 m use.

METHODS

We conducted an observational retrospective study with patients diagnosed of endometrial cancer and FIGO stages I-II. All participants were injected technetium-99m the day prior to the surgery and underwent lymphoscintigraphy along with single-photon emission computed tomography. In addition, all patients were administered intraoperatively ICG injection to detect sentinel lymph node biopsy. The surgical staging was then completed according to the European Society for Medical Oncology preoperative risk category. Data obtained from the analysis of technetium-99m detection was compared to ICG detection.

RESULTS

A total of 53 women with endometrial cancer were included in the study, 49 (92.5%) of them showed drainage preoperatively in the single-photon emission computed tomography and/or lymphoscintigraphy. The intraoperative bilateral detection rate for technetium-99 m was 26 (49.1%) patients compared to 40 (75.5%) patients with ICG (p = 0.013). We observed a 42.5% increase in the mean number of lymph nodes retrieved by ICG compared to technetium-99m (2.85 vs 2,0 nodes; p = 0.002). We intraoperatively identified 164 lymph nodes, 104 (63.4%) located in both obturator areas and external iliac vessels.

CONCLUSION

The use of ICG for the performance of sentinel node biopsy in patients with endometrial cancer seems safe and could be superior to technetium-99 m, since it offers a higher bilateral detection rate and nodal retrieval, resulting in the possibility to perform safely less full staging lymphadenectomies.

Quantitative improvement of lymph nodes visualization of breast cancer using 99mTc-nanocolloid SPECT/CT and updated reconstruction algorithm

This study aimed to evaluate the impact of attenuation and scatter correction on the contrast to noise ratio values of SPECT and SPECT/CT images in sentinel lymph nodes scintigraphy. In addition, the effect of using an iterative reconstruction algorithm with variable iterations number and fixed subsets was also investigated. 35 patients with a total of 44 lymph nodes were recruited in the current study. SPECT/CT scans were performed 3-4 h following peri-tumoral ^99mTc-nanocolloid injection (≈1 mCi) at four points. Two image types were generated including SPECT with attenuation and scatter correction (AC-SC) and SPECT without any correction (NoAC-NoSC). The acquired projections were repeatedly reconstructed with eight subsets and 10, 20, 30 and 40 iterations. Afterwards, the calculated contrast to noise ratio values were used to investigate the effect of number of iteration and to compare the image quality of SPECT/CT and SPECT only. The mean contrast to noise (CNR) values of SPECT/CT scans were found to be 19,737, 26,418, 34,282 and 31,187 at 10, 20, 30 and 40 iterations, respectively. Whereas, the mean CNR values in SPECT (NoAC-NoSC) were as low as 8506, 10,582, 13,791 and 12,143 at 10, 20, 30 and 40 iterations, respectively. The CNR values of both SPECT and SPECT/CT improved with increasing number of iterations up to 30 iterations and then slightly decreased after 30-40 iterations. Likewise, no significant difference was found between 10 and 20 iterations (P_value = 0.06) in SPECT/CT, while a statistically significant difference was observed between 10 iterations and both 30 and 40 iterations (P_value < 0.05). It is concluded that the attenuation and scatter correction in SPECT/CT optimized the CNR values up to threefold compared to SPECT alone. Thus, a considerable improvement in the CNR values and the image quality can be obtained by increasing the iterations number to peak of 30 iterations.

Recent developments in head and neck melanoma

PURPOSE OF REVIEW

To provide an overview of recently published articles covering melanoma management of the head and neck region.

RECENT FINDINGS

Melanoma management represents a rapidly evolving field. The advent of immunotherapy has led to significant changes in diagnosis, treatment, and surveillance for these patients. Invasive interventions including completion lymph node dissection have been largely replaced with increased surveillance driven by robust data showing no significant difference in overall survival. Studies have explored various treatment regimens that offer improved outcomes with the least adverse events, with a recent trend towards neoadjuvant therapy. Research has also shifted towards better understanding genetics and biomarkers that influence response to these medications. The best means to both identify and monitor these changes is being explored. As our understanding of this complex disease process continues to grow, prognosis in patients suffering with melanoma should continue to improve.

SUMMARY

The expansion of immunotherapy use in melanoma management has led to significantly improved prognosis in diagnosed patients. Present research is largely focused on better understanding the ideal patient populations, dosing, and surveillance for these therapies. Data from these studies will be crucial in better staging and treating patients with melanoma.

Sentinel Lymph Node Biopsy in Breast Cancer with 99mTc-Tilmanocept: A Multicenter Study on Real-Life Use of a Novel Tracer

^99mTc-tilmanocept is a novel radiopharmaceutical for sentinel lymph node (SLN) biopsy in breast cancer. Our aim was to describe results with ^99mTc-tilmanocept in a heterogeneous group of breast cancer patients scheduled for SLN biopsy. Methods: Radiotracer preparation followed the manufacturer's indications. Local protocols for SLN detection within 9 participant centers were not changed for the entire duration of the study. In total, 344 patients with T1-T4, N0-N2 breast cancer (352 lesions) were included. Superficial (intradermal or periareolar) or deep (peritumoral or intratumoral) injections were performed. The doses were adjusted depending on the scheduled time for surgery. Results: Lymphoscintigraphy was able to depict at least 1 SLN in 339 of 352 breast lesions (96.3%), and the intraoperative SLN detection rate reached 97.2%. On univariable analysis, SLN detection rates did not differ by age, clinical T or N stage, tumor location, histologic subtype, or prior neoadjuvant therapy. Lymphoscintigraphy showed higher SLN detection in patients with a normal weight (body mass index < 25) than in those who were overweight or obese (body mass index ≥ 25), at 99.2% versus 94.6%, respectively (P = 0.031). The proportion of patients with preoperative lymphoscintigraphic detection or excised SLNs was higher with superficial than deep injections. Reinjected cases were significantly lower when superficial injection was chosen first (P < 0.001). Injection site and the tumor markers human epidermal growth factor receptor 2 and estrogen receptor had an impact on preoperative SLN visualization and intraoperative localization. In 80 cases, SLN biopsy resulted in a positive lymph node. During a mean follow-up of 19 mo, no axillary recurrences were observed. Conclusion: Whatever the protocol, ^99mTc-tilmanocept showed good results in a heterogeneous breast cancer population, although the best results were achieved when a superficial injection was chosen.

Mapping sentinel lymph nodes in cutaneous melanoma: a vast array of perioperative imaging modalities

Sentinel lymph node biopsy (SLNB) is a decisive step in the staging process of melanoma, critically impacting patients' oncological outcome and driving the decision-making process. SLNB limits the extent of the dissection in cases where no metastases are found. Conversely, when metastases are detected, SLNB has the potential to improve regional control of the disease when complete lymphadenectomy or early administration of adjuvant treatment are indicated. Thus, accurately identifying sentinel lymph nodes represents an important prognostic factor. Several strategies have been studied, including novel procedures that are not commonly used in the clinical setting. This review highlights the different tracers, preoperative and intraoperative imaging modalities studied to perform SLNB in cutaneous melanoma. The development of innovative modalities has been fueled by a need to optimize current approaches, offering new alternatives that can overcome some of the limitations of the standard method.

Sentinel-Lymph-Node Multicenter Trials

Well executed multicenter clinical trials often provide significant evidence and support for, or against, foundational aspects of clinical procedures perceived to improve clinical management of a medical condition. In this review, discussed are reports of multicenter clinical trials designed to investigate sentinel lymph node biopsy procedures in seven types of cancer: breast, melanoma, head and neck, gastric, colon, uterine, and vulvar-with focus on the most recent reports of the hypotheses, objectives, parameters, data, results, implications, and impacts of the included trials. Such trials generally enroll more subjects, in shorter time periods, than do single-center studies. Such studies generally also have greater diversities among investigator practitioners and investigative environments than do single-center studies. The greater number of subjects provides more power to statistical analyses performed in such studies. The more rapid accrual usually results in data being more consistently acquired. The diversities of practitioners and environments may produce results that are more conservative than might be obtained from more "focused" studies; however, diversities in a study often identify implicitly results that are more robust-that is results applicable by more practitioners and applicable in more environments.

Sentinel Node Imaging and Radioguided Surgery in the Era of SPECT/CT and PET/CT: Toward New Interventional Nuclear Medicine Strategies

We review recent technological advances and new clinical indications for sentinel node (SN) and radioguided surgery in order to delineate future tendencies of interventional nuclear medicine in this field. A literature research was performed in PubMed to select relevant articles to be used as key references for analysis of the current approaches and tendencies in SN and radioguided surgery, as well as the evolving contribution of nuclear medicine intervention techniques to the various clinical applications. For classic indications such as melanoma and breast cancer, the incorporation of the SN approach based on the combined use of existing and new preoperative and intraoperative technologies in high-risk patient categories is becoming an emerging area of clinical indication. For SN biopsy staging in other malignancies with more complex lymphatic drainage, the incorporation of sophisticated tools is most helpful. The consecutive use of PET/CT and the SN procedure is increasing as a potential combined approach for the management of specific areas such as the axilla and the pelvis in patients at high risk of regional dissemination. Also, for the management of locoregional metastasis and oligometastatic disease, interventional nuclear medicine techniques are becoming valuable alternatives. The extended experience with SN biopsy is leading to technological advances facilitating the incorporation of this procedure to stage other malignancies with complex lymphatic drainage. New nuclear medicine-based approaches, incorporating SPECT/CT and PET/CT to guide resection of SNs and occult metastases, have recently been gaining ground.

Hybrid Indocyanine Green-99mTc-nanocolloid for Single-photon Emission Computed Tomography and Combined Radio- and Fluorescence-guided Sentinel Node Biopsy in Penile Cancer: Results of 740 Inguinal Basins Assessed at a Single Institution

BACKGROUND

Sentinel node (SN) biopsy in penile cancer (PeCa) is typically performed using ^99mTc-nanocolloid and blue dye. Recent reports suggested that the hybrid (radioactive and fluorescent) tracer indocyanine green (ICG)-^99mTc-nanocolloid may improve intraoperative optical SN identification.

OBJECTIVE

The current study aimed to confirm the reliability of ICG-^99mTc-nanocolloid and to assess whether blue dye is still of added value.

DESIGN, SETTING, AND PARTICIPANTS

A total of 400 ≥T1G2N0 PeCa patients were staged with SN biopsy at a single European centre. SNs were preoperatively identified with lymphoscintigraphy and single-photon emission computed tomography. Intraoperatively, SNs were detected via gamma tracing, blue staining, and fluorescence imaging.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

All patients (n=400, 740 groins) received ICG-^99mTc-nanocolloid. Intraoperative SN identification rates were retrospectively evaluated. In those patients who received ICG-^99mTc-nanocolloid and blue dye (n=266, 492 groins), SN visualisation rates were compared using the McNemar test.

RESULTS AND LIMITATIONS

In total, 740 groins were assessed. No tracer-related (allergic) reactions were reported. All preoperatively defined SNs (n=1163) were localised intraoperatively. Of all excised SNs, 98% were detectable with gamma probe and 96% were visible with fluorescence imaging. In the analysis of the patients who received ICG-^99mTc-nanocolloid and blue dye, fluorescence imaging yielded a 39% higher SN detection rate than blue dye (95% confidence interval 36-43%, p<0.001). Of the SNs that were tumour positive, 100% were intraoperatively visualised by fluorescence imaging, whereas merely 84% of the positive nodes stained blue.

CONCLUSIONS

This study confirms that ICG-^99mTc-nanocolloid is a reliable SN tracer for PeCa that significantly improves optical SN detection over blue dye.

PATIENT SUMMARY

Hybrid indocyanine green (ICG)-^99mTc-nanocolloid is a safe and reliable sentinel node (SN) tracer, as established in this large series of 400 penile cancer patients (740 groins). It enables accurate pre- and intraoperative SN identification and significantly improves SN detection rate compared with blue dye, without staining the surgical field or the need for an additional injection.

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.

Individualized Prophylactic Neck Irradiation in Patients with cN0 Head and Neck Cancer Based on Sentinel Lymph Node(s) Identification: Definitive Results of a Prospective Phase 1-2 Study

PURPOSE

This prospective, nonrandomized, interventional phase 1-2 study investigated the individualization of elective node irradiation in clinically N0 head and neck squamous cell carcinoma by sentinel lymph node (SLN) mapping with single-photon emission computed tomography/computed tomography (SPECT/CT) and its impact on tumor control and radiation-related toxicity.

METHODS AND MATERIALS

Forty-four patients with clinically N0 head and neck squamous cell carcinoma treated with definitive (chemo-)radiation therapy were imaged with SPECT/CT after ^99mTc nanocolloid injection around the tumor. The neck levels containing up to the 4 hottest SLNs were selected for prophylactic irradiation. A comparative virtual planning was performed with the selection of neck levels based on the current international guidelines. Regional control was monitored as a function of the selected volume. Dosimetric data for the organs at risk were compared between the plans. Normal tissue complication probability (NTCP) rates were derived for xerostomia, dysphagia, and hypothyroidism to predict the clinical benefit and correlated to quality-of-life (QoL) assessments at 6 months.

RESULTS

Sixteen percent of patients presented unpredicted lymphatic drainage, and 48% drained unilaterally. The nodal clinical target volume based on lymphoscintigraphy was smaller than the nodal clinical target volume based on international guidelines by a factor of 2 (P < .0001). After a median follow-up of 46 months, only 1 patient experienced a regional relapse in a nonirradiated area. Significant median dose reductions to organs at risk were observed, particularly to contralateral salivary glands in patients with unilateral drainage (14.6-28.1 Gy) and to the thyroid gland in all patients (22.4-48.9 Gy). Median NTCP reductions were observed for xerostomia (0.3% to 13.7%), dysphagia (1.7% to 10.8%), and hypothyroidism (14.0% to 36.1%). QoL at 6 months was improved, particularly in patients irradiated unilaterally.

CONCLUSIONS

Neck SLN mapping with SPECT/CT individualizes and reduces the elective nodal target volumes without compromising the regional control. The NTCP rates were reduced and favorable QoL were observed in all patients, particularly in the case of unilateral irradiation.

99mTc-68Ga-ICG-Labelled Macroaggregates and Nanocolloids of Human Serum Albumin: Synthesis Procedures of a Trimodal Imaging Agent Using Commercial Kits

Recent developments in sentinel lymph node (SLN) and radio occult lesion localization (ROLL) highlight the need for a multimodal contrast agent, providing better presurgical PET imaging and improved intraoperative mapping thanks to fluorescence detection. For this reason, we have studied a trimodal SLN/ROLL targeting agent (^99mTc-⁶⁸Ga-ICG) with commercially available kits of macroaggregated or nanocolloidal albumin (MA/NC-HSA). ⁶⁸Ga PET imaging does provide better spatial resolution and makes it possible to predict signal intensity during surgery. The presence of ^99mTc assesses the efficacy of these compounds in vitro and also during the surgery procedure. The aim of this study was to optimise the labelling and tagging of these two radiopharmaceuticals and assess their yields and stability. Kits of MA/NC-HSA particles (Pulmocis® and NanoAlbumon®) were used for sequential radiolabelling with ^99mTc and ⁶⁸Ga. Fluorescent tagging was performed using indocyanine green, a tricarbocyanine dye. The ITLC radiochemical purity of the trilabelled MA/NC-HSA was >95%. Fluorescent purity was measured by scanning the strips with a PhotoDynamicEye probe. Finally, in vitro stability tests, performed with DTPA and human serum solutions, assessed the efficacy of fluorescent tagging and radiolabelling.

Sentinel Node Identification in Melanoma: Current Clinical Impact, New Emerging SPECT Radiotracers and Technological Advancements. An Update of the Last Decade

BACKGROUND

Melanoma is the most lethal skin cancer with a mortality rate of 262 cases per 100.000 cases. The sentinel lymph node (SLN) is the first lymph node draining the tumor. SLN biopsy is a widely accepted procedure in the clinical setting since it provides important prognostic information, which helps patient management, and avoids the side effects of complete lymph node dissection. The rationale of identifying and removing the SLN relies on the low probability of subsequent metastatic nodes in case of a negative histological exam performed in the SLN.

DISCUSSION

Recently, new analytical approaches, based on the evaluation of scintigraphic images are also exploring the possibility to predict the metastatic involvement of the SLN. 99mTc-labeled colloids are still the most commonly used radiotracers but new promising radiotracers, such as 99mTc- Tilmanocept, are now on the market. In the last decades, single photon emission computed tomography- computerized tomography (SPECT/CT) has gained wider diffusion in clinical departments and there is large evidence about its superior diagnostic accuracy over planar lymphoscintigraphy (PL) in the detection of SLN in patients with melanoma. Scientists are also investigating new hybrid techniques combining functional and anatomical images for the depiction of SLN but further evidence about their value is needed.

CONCLUSION

This review examined the predictive and prognostic factors of lymphoscintigraphy for metastatic involvement of SLN, the currently available and emerging radiotracers and the evidence of the additional value of SPECT/CT over PL for the identification of SLN in patients with melanoma. Finally, the review discussed the most recent technical advances in the field.

Malignant Cutaneous Melanoma: Updates in PET Imaging

BACKGROUND

Cutaneous malignant melanoma is a neoplasm whose incidence and mortality are dramatically increasing. 18F-FDG PET/CT gained clinical acceptance over the past 2 decades in the evaluation of several glucose-avid neoplasms, including malignant melanoma, particularly for the assessment for distant metastases, recurrence and response to therapy.

OBJECTIVE

To describe the advancements of nuclear medicine for imaging melanoma with particular attention to 18F-FDG-PET and its current state-of-the-art technical innovations.

METHODS

A comprehensive search strategy was used based on SCOPUS and PubMed databases. From all studies published in English, we selected the articles that evaluated the technological insights of 18FFDG- PET in the assessment of melanoma.

RESULTS

State-of-the-art silicon photomultipliers based detectors ("digital") PET/CT scanners are nowadays more common, showing technical innovations that may have beneficial implications for patients with melanoma. Steady improvements in detectors design and architecture, as well as the implementation of both software and hardware technology (i.e., TOF, point spread function, etc.), resulted in significant improvements in PET image quality while reducing radiotracer dose and scanning time.

CONCLUSION

Recently introduced digital PET detector technology in PET/CT and PET/MRI yields higher intrinsic system sensitivity compared with the latest generation analog technology, enabling the detection of very small lesions with potential impact on disease outcome.

Comparison between planar, SPECT and SPECT/computed tomography systems in 99mTc- nanocolloid sentinel lymph node imaging: phantom design and clinical investigations

PURPOSE

It was aimed to examine the performance of planar, SPECT and SPECT/CT in lymph nodes detection of breast cancer.

MATERIALS AND METHODS

In-house made phantom was immersed in water-filled container. Disparate activities were injected into spheres emulating breast tumour (1.5 cm), and adjacent lymph nodes (1, 0.5 and 0.25 cm). Planar, SPECT and SPECT/CT scans were made at depths of 1, 3, 5, 7 and 9 cm. Rose Criteria was employed to investigate the detectability in planar imaging, and contrast to noise ratios (CNRs) were used in SPECT and SPECT/CT images. SPECT and SPECT/CT of 20 patients were randomly incorporated in the current study.

RESULTS

CNR values from planar images at 1 cm depth for the simulated nodes of 1, 0.5and 0.25 cm were 36, 18 and 17, respectively. Whereas, those from SPECT/CT were 94.5, 63.3 and 20.9, repectively. CNRs from SPECT were lower than SPECT/CT in order of 60.1, 41.8 and 17.1 at the same depth. At 9 cm, CNR values of 1, 0.5 and 0.25 cm from the planar images were 14, 6 and 5, respectively. While CNR values from SPECT were higher as 53.6, 38.0, and 14.9, respectively, and the greatest CNRs were in SPECT/CT as 85.7, 55.8, and 19.1, repectively.

CONCLUSION

The CNR values in SPECT/CT were 1.5- and 3.5-folds higher than SPECT and planar imaging at depth range 1-9 cm. The patients study exhibited larger SPECT/CT CNRs over SPECT as great as 1.6-fold.

Utility of Quantitative SPECT/CT Lymphoscintigraphy in Guiding Sentinel Lymph Node Biopsy in Head and Neck Melanoma

PURPOSE

To investigate the use of advanced SPECT/CT quantification in guiding surgical selection of positive sentinel lymph nodes (SLNs) in head and neck melanoma.

METHODS

We retrospectively reviewed data from patients with cutaneous head and neck melanoma who underwent lymphoscintigraphy with SPECT/CT prior to SLN biopsy (SLNB). Quantification of radiotracer uptake from SPECT/CT data was performed using in-house segmentation software. SLNs identified using SPECT/CT were compared to SLNs identified surgically using an intraoperative γ-probe. A radioactivity count threshold using SPECT/CT for detecting a positive SLN was calculated.

RESULTS

One hundred and five patients were included. Median number of SLNs detected was 3/patient with SPECT/CT and 2/patient with intraoperative γ-probe. The hottest node identified by SPECT/CT and intraoperative γ-probe were identical in 85% of patients. All 20 histologically positive SLNs were identified by SPECT/CT and γ-probe. On follow-up, all nodal recurrences occurred at lymph node levels with the hottest node identified by SPECT/CT and either the hottest or second hottest node identified by γ-probe during SLNB. Using our data, a SPECT/CT radioactivity count threshold of 20% would eliminate the unnecessary removal of 11% of SPECT/CT identified nodes and 12% of intraoperatively detected nodes.

CONCLUSION

Utilizing SPECT/CT quantification, we propose that a radioactivity count threshold can be developed to help guide the selective removal of lymph nodes in head and neck SLNB. Furthermore, the nodal level containing the hottest node identified by SPECT/CT quantification must be thoroughly investigated for SLNs and undergo careful follow-up and surveillance for recurrence.

Nonsurgical Management of Lymph Node Basins in Melanoma

In this article we provide a critical review of the evidence available for surgical management of the nodal basin in melanoma, with an aim to ensure an understanding of risks and benefits for all lymph node surgery offered to patients, and alternatives to surgical management where appropriate.

SPECT/CT and fusion ultrasound to target the efferent groin lymph node for lymphatic surgery

INTRODUCTION

Pelvic lymphadenectomy (PL) causes changes to the inguinal lymph nodes with progressive loss of immune and lymphatic pump function. Efferent lymphatic vessel-to-venous anastomosis (ELVA) has been reported to address this problem. The aim of this report was to describe the feasibility of the SPECT/CT combined with ultrasound fusion imaging (UFI) to target the groin efferent lymph node (GELN) for ELVA.

PATIENTS AND METHODS

Twelve patients with lower limb lymphedema after PL were scheduled for peripheric lymphaticovenular anastomosis (LVA) combined with ELVA. All-patients were clinically ISL-stage1, with good visualization of the inguinal lymph nodes at preoperative lymphoscintigraphy. The mean patient age was 55.4 years and the mean BMI was 25.5.The mean limb circumference (MLC) was calculated before surgery and 1 year after surgery. The LymQoL-Leg questionnaire was administered before surgery and 6 months after surgery. Before surgery, the GELN was identified by SPECT/CT and its location was marked on the skin by UFI virtual navigation. Peripheric LVA sites were planned by ultrasound and indocyanine green (ICG) lymphography. Pre and postoperative MLC and LymQoL-Leg scores were compared.

RESULTS

In all-patients, the SPECT/CT succeeded at detecting and targeting the GELN. In all-patients, real-time anatomical coregistration with US was feasible, and it was possible to mark on the groin skin the depth and position of the GELN on the skin at the groin. During surgery, in every patient, we found the GELN marked before surgery and performed ELVA. We also performed two or three peripheric LVAs in every patient. The mean value of MLC decreased (38.2 ± 2.13 cm vs. 36.33 ± 2.14 cm; p = .04) and the mean score of the LymQoL-Leg questionnaire improved (9.3 ± 1.7 vs. 7.7 ± 1.1; p = .02).

CONCLUSION

SPECT/CT combined with UFI is feasible for the preoperative identification of GELN for ELVA.

Stage Two Malignant Melanoma of the Clitoris: A Case Report

Mucosal melanomas are rare in comparison to cutaneous melanomas, accounting for approximately 1% of all melanoma cases. Vulvovaginal melanoma is the least common mucosal melanoma subtype. For patients without distant metastases at presentation, regional lymph node involvement is the most important prognostic indicator. Lymphoscintigraphy is a method used to identify the sentinel lymph node (SLN), directing subsequent biopsies to the lymph node at highest risk for cancer spread. We present a 67-year-old Hispanic female with stage II B (T4aN0M0) melanoma of the clitoris. The patient initially sought medical treatment for a pigmented vulvar lesion over her clitoris that occasionally bleeds. She stated that over the past month the lesion began to grow peripherally and then acquired a very dark color. The patient underwent local excision of the mass and subsequent pathology revealed malignant melanoma. The patient underwent lymphoscintigraphy which allowed localization and subsequent biopsy of the left inguinal sentinel node. The left inguinal sentinel node was negative for metastatic melanoma. It was opted to keep her under observation. Compared to cutaneous melanoma, patients with mucosal melanoma usually present with more advanced disease, and thus efficacious imaging practices play a significant role in the management of the disease. Lymphoscintigraphy is a well-tolerated, validated, cost-effective, and reliable method of detecting sentinel nodes with minimal radiation exposure to the patient. In our case, early clinical detection allowed for prompt surgical intervention, pathologic diagnosis, and reliable staging via lymphoscintigraphy of a rare form of malignant melanoma.

Comparison between single photon emission computed tomography with computed tomography and planar scintigraphy in sentinel node biopsy in breast cancer patients

Objective

Radio-guided sentinel node (SN) biopsy is a standard method used in the treatment of early breast cancer. Single photon emission computed tomography with computed tomography (SPECT/CT) has been commonly used for SN detection. SPECT/CT adds precise anatomical information of SN sites, and it is reported that more SNs may be detectable on SPECT/CT than on planar imaging. We here investigate which breast cancer patients have benefited from SPECT/CT over planar imaging.

Methods

A total of 273 breast cancer patients including 80 with ipsilateral breast tumor relapse (IBTR) underwent both multiple-view planar imaging and SPECT/CT for SN detection. The number of SNs, the patients who had benefitted from SPECT/CT, and the SN procedure failure rate were compared between SPECT/CT and planar imaging. Factors influencing the visualization of para-sternal and ipsilateral level II, III nodes, and contralateral axillary nodes were also analyzed using logistic regression analysis.

Results

The number of hot spots did not differ between SPECT/CT and multiple-view planar imaging. Eight contaminated patients and 52 patients with visualized extra-level I axillary nodes benefited from identifying precise anatomical sites. Even though radioactive nodes could be harvested in most (192/193) of the non-IBTR patients (7/8 in non-SN visible patients), no radioactive nodes could be found during surgery in 11 of 80 IBTR patients. Axillary surgery (dissection) increased the visualization of para-sternal and level II, III axillary nodes, and previous irradiation increased the visualization of contralateral axillary nodes.

Conclusion

Multiple-view planar imaging was equivalent to SPECT/CT for depicting hot nodes for radio-guided SN detection in breast cancer. SPECT/CT was useful when precise anatomical information was necessary, especially regarding sentinel lymph nodes other than ipsilateral axilla. Logistic regression analysis revealed that axillary surgery (dissection) increased the visualization of para-sternal and level II, III axillary nodes, and the only relevant factor influencing visualization of contralateral axillary SNs was previous radiation to the breast.

Melanoma & nuclear medicine: new insights & advances

The contribution of nuclear medicine to management of melanoma patients is increasing. In intermediate-thickness N0 melanomas, lymphoscintigraphy provides a roadmap for sentinel node biopsy. With the introduction of single-photon emission computed tomography images with integrated computed tomography (SPECT/CT), 3D anatomic environments for accurate surgical planning are now possible. Sentinel node identification in intricate anatomical areas (pelvic cavity, head/neck) has been improved using hybrid radioactive/fluorescent tracers, preoperative lymphoscintigraphy and SPECT/CT together with modern intraoperative portable imaging technologies for surgical navigation (free-hand SPECT, portable gamma cameras). Furthermore, PET/CT today provides 3D roadmaps to resect 18F-fluorodeoxyglucose-avid melanoma lesions. Simultaneously, in advanced-stage melanoma and recurrences, 18F-fluorodeoxyglucose-PET/CT is useful in clinical staging and treatment decision as well as in the evaluation of therapy response. In this article, we review new insights and recent nuclear medicine advances in the management of melanoma patients.