Guidelines for lymphoscintigraphy and F18 FDG PET scans in melanoma

Clinical practice consensus for the diagnosis and management of melanoma in Taiwan

Melanoma is rare in Taiwan. Asian melanoma is distinct from Western melanoma because acral and mucosal melanoma accounts for the majority of melanoma cases, leading to distinct tumor behaviors and genetic profiling. With consideration of the clinical guidelines in Western countries, Taiwanese experts developed a local clinical practice consensus guideline. This consensus includes diagnosis, staging, and surgical and systemic treatment, based only on clinical evidence, local epidemiology, and available resources evaluated by experts in Taiwan. This consensus emphasizes the importance of surgical management, particularly for sentinel lymph node biopsies. In addition, molecular testing for BRAF is mandatory for patients before systemic treatment. Furthermore, immunotherapy and targeted therapy are prioritized for systemic treatment. This consensus aimed to assist clinicians in Taiwan in diagnosing and treating patients according to available evidence.

Prognostic Significance and Management of Sentinel Nodes in the Triangular Intermuscular Space of Patients with Melanoma

BACKGROUND

The clinical significance of sentinel nodes (SNs) in the triangular intermuscular space (TIS) of patients with melanoma is poorly understood. This study aimed to determine their incidence and positivity rate, and to report their management and patient outcomes.

METHODS

This was a single-institution retrospective cohort study of patients with unilateral or bilateral TIS SNs on lymphoscintigraphy treated between 1992 and 2017. Recurrence-free survival was analyzed.

RESULTS

Lymphoscintigraphy identified TIS SNs in 266 patients. They were bilateral in 17 patients. Of the 2296 patients with a melanoma on the upper back, 259 (11%) had TIS SNs. Procurement of SNs was not attempted in 122 (43%) of the 283 cases and failed in 11 cases (7%). An SN was successfully retrieved from the TIS in 145 patients (53%) and contained metastasis in 18 of 150 TIS SNs. This was the only positive SN in 12 patients (8%), upstaging all of them. Of the 18 patients with a positive SN in the TIS, 9 (50%) underwent completion axillary lymph node dissection, but no additional involved nodes were found in any of these patients. Recurrence in the TIS was observed in six patients (5%), none of whom had their TIS SN surgically pursued previously.

CONCLUSIONS

Lymphoscintigraphy showed TIS SNs in 11% of patients with melanomas on their upper back. In such cases, retrieval of TIS SNs is required for accurate staging and to minimize the risk of TIS recurrence.

Cancer immunotherapy is accompanied by distinct metabolic patterns in primary and secondary lymphoid organs observed by non-invasive in vivo 18F-FDG-PET

Purpose: Cancer immunotherapy depends on a systemic immune response, but the basic underlying mechanisms are still largely unknown. Despite the very successful and widespread use of checkpoint inhibitors in the clinic, the majority of cancer patients do not benefit from this type of treatment. In this translational study, we investigated whether noninvasive in vivo positron emission tomography (PET) imaging using 2-[¹⁸F]fluoro-2-deoxy-D-glucose (¹⁸F-FDG) is capable of detecting immunotherapy-associated metabolic changes in the primary and secondary lymphoid organs and whether this detection enables the prediction of a successful anti-cancer immune response. Methods: RIP1-Tag2 mice with progressed endogenous insular cell carcinomas underwent a combined cancer immunotherapy consisting of CD4⁺ T cells plus monoclonal antibodies (mAbs) against programmed death ligand-1 (PD-L1) and lymphocyte activation gene-3 (LAG-3) or a sham treatment after radiation-mediated immune cell depletion. A second cohort of RIP1-Tag2 mice underwent exclusive checkpoint inhibitor therapy (CIT) using anti-PD-L1/LAG-3 mAbs or sham treatment without initial immune cell depletion to mimic the clinical situation. All mice were monitored by ¹⁸F-FDG-PET combined with anatomical magnetic resonance imaging (MRI). In addition, we retrospectively analyzed PET / computed tomography (CT) scans (PET/CT) regarding ¹⁸F-FDG uptake of CIT-treated metastatic melanoma patients in the spleen (n=23) and bone marrow (BM; n=20) as well as blood parameters (n=17-21). Results: RIP1-Tag2 mice with advanced insular cell carcinomas treated with combination immunotherapy exhibited significantly increased ¹⁸F-FDG uptake in the spleen compared to sham-treated mice. Histopathology of the spleens from treated mice revealed atrophy of the white pulp with fewer germinal centers and an expanded red pulp with hyperplasia of neutrophils than those of sham-treated mice. Immunohistochemistry and flow cytometry analyses of the spleens revealed a lower number of T cells and a higher number of neutrophils compared to those in the spleens of sham-treated mice. Flow cytometry of the BM showed enhanced activation of T cells following the treatment schemes that included checkpoint inhibitors. The ratio of ¹⁸F-FDG uptake at baseline to the uptake at follow-up in the spleens of exclusively CIT-treated RIP1-Tag2 mice was significantly enhanced, but the ratio was not enhanced in the spleens of the sham-treated littermates. Flow cytometry analysis confirmed a reduced number of T cells in the spleens of exclusively CIT-treated mice compared to that of sham-treated mice. A retrospective analysis of clinical ¹⁸F-FDG-PET/CT scans revealed enhanced ¹⁸F-FDG uptake in the spleens of some successfully CIT-treated patients with metastatic melanoma, but there were no significant differences between responders and non-responders. The analysis of the BM in clinical ¹⁸F-FDG-PET/CT scans with a computational segmentation tool revealed significantly higher baseline ¹⁸F-FDG uptake in patients who responded to CIT than in non-responders, and this relationship was independent of bone metastasis, even in the baseline scan. Conclusions: Thus, we are presenting the first translational study of solid tumors focusing on the metabolic patterns of primary and secondary lymphoid organs induced by the systemic immune response after CIT. We demonstrate that the widely available ¹⁸F-FDG-PET modality is an applicable translational tool that has high potential to stratify patients at an early time point.

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.

Current management of patients with melanoma who are found to be sentinel node-positive

Background

The results of the DeCOG‐SLT and MSLT‐II studies, published in 2016 and mid‐2017, indicated no survival benefit from completion lymph node dissection (CLND) in melanoma patients with positive sentinel nodes (SNs). Subsequently, several studies have been published reporting a benefit of adjuvant systemic therapy in patients with stage III melanoma. The current study assessed how these findings influenced management of SN‐positive patients in a dedicated melanoma treatment centre.

Methods

SN‐positive patients treated at Melanoma Institute Australia between July 2017 and December 2018 were prospectively identified. Surgeons completed a questionnaire documenting the management of each patient. Information on patients, primary tumours, SNs, further treatment and follow‐up was collected from patient files, the institutional research database and pathology reports.

Results

During the 18‐month study period, 483 patients underwent SN biopsy. A positive SN was found in 61 (13%). Two patients (3%) requested CLND because of anxiety about observation in view of unfavourable primary tumour and SN characteristics. The other 59 patients (97%) were followed with a four‐monthly ultrasound examination of the relevant lymph node field(s). Two of them (3%) developed an isolated nodal recurrence after 4 and 11 months of follow‐up. Fifty‐seven patients (93%) were seen following the publication of the first two adjuvant systemic therapy studies in November 2017; 46 (81%) were referred to a medical oncologist to discuss adjuvant systemic therapy, which 32 (70%) chose to receive.

Conclusion

At Melanoma Institute Australia most patients with an involved SN are now managed without CLND. The majority are referred to a medical oncologist and receive adjuvant systemic therapy.

Focused Ultrasound Surveillance of Lymph Nodes Following Lymphoscintigraphy Without Sentinel Node Biopsy: A Useful and Safe Strategy in Elderly or Frail Melanoma Patients

BACKGROUND

Sentinel node (SN) biopsy (SNB) has become standard of care in clinically localized melanoma patients. Although it is minimally invasive, advanced age and/or comorbidities may render SNB inadvisable in some patients. Focused ultrasound follow-up of SNs identified by preoperative lymphoscintigraphy may be an alternative in these patients. This study examines the outcomes in patients managed in this way at a major melanoma treatment center.

METHODS

All patients with clinically localized cutaneous melanoma who underwent lymphoscintigraphy and in whom SNB was intentionally not performed due to advanced age and/or comorbidities were included.

RESULTS

Between 2000 and 2009, 160 patients (5.2% of the total) underwent lymphoscintigraphy without SNB because of advanced age and/or comorbidities. Compared with the 2945 patients who had a SNB, the 160 patients were older, had thicker melanomas that were more often located in the head and neck region, and had more SNs in more nodal regions. Of the 160 patients, 150 (94%) were followed with ultrasound examination of their SNs at each follow-up visit; this identified 33% of the nodal recurrences before they became clinically apparent. Compared with SN-positive patients who were treated by completion lymph node dissection, observed patients who developed nodal recurrence had more involved nodes when a delayed lymphadenectomy was performed. Melanoma-specific survival, recurrence-free survival, and distant recurrence-free survival rates were similar, while regional lymph node-free survival was worse.

CONCLUSIONS

Lymphoscintigraphy with focused ultrasound follow-up of SNs is a reasonable management alternative to SNB in patients who are elderly and/or have substantial comorbidities.

External validation of a prognostic model to predict survival of patients with sentinel node-negative melanoma

Background

Identifying patients with sentinel node‐negative melanoma at high risk of recurrence or death is important. The European Organisation for Research and Treatment of Cancer (EORTC) recently developed a prognostic model including Breslow thickness, ulceration and site of the primary tumour. The aims of the present study were to validate this prognostic model externally and to assess whether it could be improved by adding other prognostic factors.

Methods

Patients with sentinel node‐negative cutaneous melanoma were included in this retrospective single‐institution study. The β values of the EORTC prognostic model were used to predict recurrence‐free survival and melanoma‐specific survival. The predictive performance was assessed by discrimination (c‐index) and calibration. Seeking to improve the performance of the model, additional variables were added to a Cox proportional hazards model.

Results

Some 4235 patients with sentinel node‐negative cutaneous melanoma were included. The median follow‐up time was 50 (i.q.r. 18·5–81·5) months. Recurrences and deaths from melanoma numbered 793 (18·7 per cent) and 456 (10·8 per cent) respectively. Validation of the EORTC model showed good calibration for both outcomes, and a c‐index of 0·69. The c‐index was only marginally improved to 0·71 when other significant prognostic factors (sex, age, tumour type, mitotic rate) were added.

Conclusion

This study validated the EORTC prognostic model for recurrence‐free and melanoma‐specific survival of patients with negative sentinel nodes. The addition of other prognostic factors only improved the model marginally. The validated EORTC model could be used for personalizing follow‐up and selecting high‐risk patients for trials of adjuvant systemic therapy.

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.

Outcome of Melanoma Patients Who Did Not Proceed to Sentinel Node Biopsy After Preoperative Lymphoscintigraphy

BACKGROUND

At our institution, a planned sentinel node biopsy (SNB) procedure is occasionally canceled after preoperative lymphoscintigraphy. This study reports the frequency of this, the reasons, and the management and outcomes of these patients.

METHODS

All patients with clinically localized cutaneous melanoma treated at Melanoma Institute Australia between 2000 and 2009 whose planned SNB procedure was not undertaken after lymphoscintigraphy were included in this retrospective study.

RESULTS

Of the 3148 patients in whom the procedure had been planned, 203 patients (6.4 %) did not have a SNB. The main reason for not proceeding with SNB (in 84 % of cases) was the lymphoscintigraphic demonstration of multiple drainage fields and/or multiple sentinel nodes (SNs). Patients who did not proceed to SNB were significantly older than those who did, more often had melanomas of the head or neck, and had more SNs and more nodal drainage fields. Of the 203 patients, 181 (89 %) were followed with high-resolution ultrasound of their SNs, which identified 33 % of the nodal recurrences before they were clinically apparent. Patients whose SNB was canceled had significantly worse recurrence-free survival and regional node disease-free survival, but melanoma-specific survival was similar. Compared to SN-positive patients, node-positive patients without SNB had significantly more involved nodes when a delayed lymphadenectomy was performed, but melanoma-specific survival was not significantly different after a median follow-up of 42 months.

CONCLUSIONS

Lymphoscintigraphy with ultrasound follow-up of previously identified SNs is an acceptable management strategy for patients in whom a SNB procedure is likely to be challenging.

Successful treatment of triple primary tumor

INTRODUCTION

The occurrence of multiple primary tumors is rare. Only limited number of cases with triple malignancy have been reported. We report here a rare case of a woman presented synchronous triple tumors, in her lung, breast, skin.

PRESENTATION OF CASE

A 56-year-old woman presented with invasive ductal carcinoma of breast, non-small cell lung cancer and malignant melanoma. The patient undergone mastectomy and malignant melanoma tumor excision on-site. After operation stereotactic radiotherapy was given to her lung tumor. Six course of chemotherapy was given to her. She is alive with no progression.

DISCUSSION

The patient was diagnosed with melanoma and staging by FDG/PET. There is not any study about routine using PET/CT in the melanoma staging.

CONCLUSION

This is a very rare synchronous triple tumor case.

Reliability of a radiological grading system for dermal backflow in lymphoscintigraphy imaging

RATIONALE AND OBJECTIVES

Lymphoscintigraphy may be used for diagnosing secondary lymphedema. Dermal backflow, the presence of radiotracer in dermal lymphatics, is a key clinical feature. Although often reported as present or absent, a scale that assesses the severity of dermal backflow has been previously developed. The aim of this study was to determine the reliability of these two methods of assessment.

MATERIALS AND METHODS

Sixteen experienced nuclear medicine physicians assessed the quantity of dermal backflow of 57 lymphoscintigraphy scans using a 4-point descriptive scale that was dichotomized for secondary analysis. Each scan included images from four time points for women previously diagnosed with secondary lymphedema (n = 47) and controls (n = 5); five scans were presented twice to examine intraobserver reliability. This was further investigated as 13 physicians viewed the scans again on an Apple iPad2. The physicians rated their confidence in their scoring. Readers were blinded to clinical history.

RESULTS

Although both the 2- and 4-point scale had moderate interobserver reliability, the reliability of the 2-point scale was slightly higher (4-point: Fleiss κ = .418, standard error [SE] = .008); 2-point: Fleiss κ = .574, SE = .013). Low interobserver reliability was found when only control subjects were considered (Fleiss κ = 0.055, SE = 0.034). Intraobserver reliability of the five repeated images varied from poor to perfect (Cohen κ = .063 to 1.00), whereas moderate to substantial intraobserver reliability (Cohen's κ = .342 to .752) was found when comparing devices. The readers were highly confident of their scores.

CONCLUSIONS

Overall, moderate intraobserver and interobserver reliability was found for quantifying dermal backflow with both the 2- and 4-point scale.