Preoperative ultrasound is not useful for identifying nodal metastasis in melanoma patients undergoing sentinel node biopsy: preoperative ultrasound in clinically node-negative melanoma

Cutaneous melanoma

Cutaneous melanoma is a malignancy arising from melanocytes of the skin. Incidence rates are rising, particularly in White populations. Cutaneous melanoma is typically driven by exposure to ultraviolet radiation from natural sunlight and indoor tanning, although there are several subtypes that are not related to ultraviolet radiation exposure. Primary melanomas are often darkly pigmented, but can be amelanotic, with diagnosis based on a combination of clinical and histopathological findings. Primary melanoma is treated with wide excision, with margins determined by tumour thickness. Further treatment depends on the disease stage (following histopathological examination and, where appropriate, sentinel lymph node biopsy) and can include surgery, checkpoint immunotherapy, targeted therapy, or radiotherapy. Systemic drug therapies are recommended as an adjunct to surgery in patients with resectable locoregional metastases and are the mainstay of treatment in advanced melanoma. Management of advanced melanoma is complex, particularly in those with cerebral metastasis. Multidisciplinary care is essential. Systemic drug therapies, particularly immune checkpoint inhibitors, have substantially increased melanoma survival following a series of landmark approvals from 2011 onward.

Dermatologic Follow-up and Assessment of Suspicious Lesions

As our knowledge and understanding of melanoma evolve, melanoma surveillance guidelines will reflect these findings. Currently, there is no consensus across international guidelines for melanoma follow-up. However, it is accepted that more aggressive surveillance is recommended for more advanced disease. When examining high-risk individuals, a systematic approach should be followed. Future considerations include the use of noninvasive imaging techniques, 'liquid biopsies,' and artificial intelligence to enhance detection of melanomas.

The value of lymph node ultrasound and whole body 18F-FDG PET/CT in stage IIB/C melanoma patients prior to SLNB

BACKGROUND

Stage IIB/IIC (8th AJCC) melanoma patients are known to have high-risk primary tumors, however they follow the same routine to sentinel lymph node biopsy (SLNB) as more low risk tumors. Guidelines are not conclusive regarding the use of preoperative imaging for these patients. The aim of this pilot study was to assess the value of ultrasound (US) and 18F-FDG PET/CT prior to lymphoscintigraphy (LSG) and SLNB for stage IIB/C melanoma patients.

METHODS

From 2019-04 till 2020-01, all stage IIB/C melanoma patients underwent US of the regional lymph nodes and whole body 18F-FDG PET/CT before their planned LSG and SLNB. Suspected metastases were confirmed with fine needle aspiration (FNA), prior to surgery.

RESULTS

In total 23 patients were screened: six had metastases detected by imaging, two by US, one by 18F-FDG PET/CT and three were detected by both imaging modalities. All metastases were nodal and therefore treatment was altered to lymph node dissection and all but one also received adjuvant therapy. Eight (47%) of the 17 patients without macroscopic disease, still had a positive SN. Sensitivity, specificity and false negative rate for US and 18F-FDG PET/CT were 36%, 89%, 64% and 29%, 100% and 71%, respectively.

CONCLUSION

Preoperative negative imaging does not exclude the presence of SN metastases, therefore SLNB cannot be foregone. However, US detected metastases in 22% of patients, altering their treatment, which suggests it is effective in the work-up of stage IIB/C melanoma. Staging with 18F-FDG PET/CT is not of added value prior to LSG and SLNB and should therefore not be used.

Staging Melanoma: What's Old and New

The melanoma expert panel devised the evidence-based eighth edition American Joint Committee on Cancer staging system by conducting vigorous analyses of stage I, II, and III patients from the International Melanoma Database and Discovery Platform. Key changes in the eighth edition are regarding subcategorization of T1, M1, pathologic stage grouping of stage I and III, and refining the definitions and terminologies used in the staging system. As the knowledge of tumor biology improves, the staging of melanoma will continue to evolve to enable betterment of care.

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.

Melanoma patient imaging in the era of effective systemic therapies

Imaging plays a critical role in the current multi-disciplinary management of patients with melanoma. It is used for primary disease staging, surgical planning, and surveillance in high-risk patients, and for monitoring the effects of systemic or loco-regional therapies. Several different imaging modalities have been utilised in the past. Contemporary imaging practises vary geographically depending on clinical guidelines, physician preferences, availability and cost. Targeted therapies and immunotherapies have revolutionised the treatment of patients with metastatic melanoma over the last few years. With this have come new patterns of disease that were not observed after conventional therapies, and new criteria to assess therapeutic responses. In this article we review the role of imaging for patients with melanoma in the era of effective systemic therapies and discuss likely future developments.

Gamma probe and ultrasound guided fine needle aspiration cytology of the sentinel node (GULF) trial - overview of the literature, pilot and study protocol

BACKGROUND

Sentinel node (SN) biopsy (SNB) detects clinically occult metastases of breast cancer and melanoma in 20-30%. Wound infections, seroma and lymph edema occur in up to 10%. Targeted ultrasound (US) of the SN, (with fine needle aspiration cytology (FNAC) if appropriate) has been investigated as a minimally invasive alternative, but reported sensitivity rates are too low to replace SNB. Our hypothesis is that the use of a handheld gamma probe concomitant with US may improve sensitivity. Our aim is to provide an overview of the current literature on preoperative nodal staging of clinical N0 melanoma patients, report on a pilot, and present a study protocol for a minimally invasive alternative to the SNB: Gamma probe and Ultrasound guided Fine needle aspiration cytology of the sentinel node (GULF trial).

METHODS

The GULF trial is a multicenter open single arm observational trial. Newly diagnosed cT1b-4N0M0 cutaneous melanoma or cT1-3N0M0 breast cancer patients, aged >18 years, presenting for SNB are eligible. 120 patients will be included for preoperative targeted gamma probe guided US and FNAC of the SN. Afterwards all patients proceed to surgical SNB. Primary endpoint is the sensitivity of FNAC. Secondary endpoints include SN identification rate and the histopathological compatibility of Core Needle Biopsy and FNAC vs. SNB. Secondary endpoints were investigated in a pilot with 10 FNACs and marker placements, and 10 FNACs combined with Core Needle Biopsy.

RESULTS

A pilot in 20 patients showed that SN identification rate was 90%, supporting the feasibility of this technique.

DISCUSSION

There is broad experience with US (in combination with FNAC) prior to SNB, but sensitivity and specificity are too low to completely abandon SNB. Promising alternative techniques potentially will replace SNB in the future but more evidence is needed in the form of prospective studies. Accurate identification of the SN for US-FNAC has been proven feasible in our pilot. When adequate sensitivity can be reached, US-FNAC provides a minimally invasive alternative for the surgical SNB procedure.

TRIAL REGISTRATION

The GULF trial is registered in the Netherlands Trial Registry (NTR), ID: NRT5193 . May 1st 2015.

Ultrasound-guided fine needle aspiration cytology as an addendum to sentinel lymph node biopsy can perfect the staging strategy in melanoma patients

BACKGROUND

Ultrasound guided fine needle aspiration cytology (US-guided FNAC) can identify microscopic involvement of lymph nodes as in breast cancer and avoid surgical sentinel node (SN). Its utility in melanoma patients is controversial and subject of this study.

METHODS

Between 2001 and 2010 over 1000 stage I/II consecutive melanoma patients prospectively underwent US-FNAC prior to SN biopsy. All patients underwent lymphoscintigraphy prior to US-FNAC. The Berlin US morphology criteria: Peripheral perfusion (PP), loss of central echoes (LCE) and balloon shaped (BS) were registered. FNAC was performed in case of presence of any of these factors. SN tumour burden was measured according to the Rotterdam criteria. All patients underwent SN or lymph node dissection (LND) in case of positive FNAC.

FINDINGS

Mean/median Breslow thickness was 2.58/1.57 mm. Mean/median follow-up was 56/53 months (1-132). SN positivity rate was 21%. US-FNAC Sensitivity was 71% (US only) and 51% (US-FNAC). Sensitivity of US-FNAC was highest for T4 (76%) and ulcerated melanomas (63%). PP, LCE and BS had sensitivity of 69%, 24% and 24% respectively. Sensitivity of US-FNAC increased with increasing SN tumour burden. PP was an early sign of metastasis (58% in <0.1mm metastases). Threshold size of a metastasis for FNAC was 0.3mm. Five-year survival correlated to US-FNAC status (95% in negative and 59% in positive).

INTERPRETATION

Ultrasound guided FNAC (US-FNAC) according to the Berlin morphology criteria could correctly identify at least half of all tumour positive sentinel nodes, prior to the surgical SN procedure. Peripheral perfusion is an early sign of metastasis, which is very sensitive, but with lower positive predictive value (PPV). It is responsible for the sensitivity of the procedure. Balloon shape is a sign of advanced metastases, with lower sensitivity, but high PPV. US-FNAC sensitivity correlated with increasing T-stage, ulceration of the primary and increasing SN tumour burden. US-FNAC status accurately predicts survival.

Accuracy of real-time ultrasound elastography in the differential diagnosis of lymph nodes in cutaneous malignant melanoma (CMM): a pilot study

BACKGROUND

We investigated the diagnostic ability of real-time elastography to differentiate between reactive and metastatic lymph nodes in cutaneous malignant melanoma (CMM) patients and to determine the optimum cutoff value for elastography scores for diagnosis CMM.

METHODS

Twenty lymph nodes (metastatic, n = 13; reactive, n = 7) from 12 patients with CMM were examined by both elastography and B-mode ultrasound in this prospective study. Elastographic patterns were given scores of 1-5 according to the percentage of high elasticity (hard) areas in the lymph node. Elastographic patterns 1, 2, 3, 4, and 5 were assigned elastography scores (ES) of 1, 2, 3, 4, and 5, respectively. B-mode ultrasound diagnosis was performed on the basis of the morphological patterns (balloon-shaped lymph node and loss of central echoes). The sensitivity, specificity, and accuracy were calculated, and receiver operating characteristic analysis was performed, comparing with elastograms and B-mode images, with histological findings as the reference standard.

RESULTS

Sensitivity, specificity, and accuracy of elastography were 100, 71, and 90 %, respectively, with an ES cutoff value of 3; 92, 100, and 95 % for elastography with an ES cutoff value of 4; and 77, 57, and 70 % for B-mode ultrasound.

CONCLUSION

Elastography can enhance the diagnostic accuracy of ultrasound for differentiating between reactive and malignant lymph nodes in CMM and might eliminate the need for sentinel lymph node biopsy. The optimum ES cutoff value for reactive versus metastatic lymph nodes is 4.

Ultrasound skin imaging

The interaction of high-frequency ultrasound waves with the skin provides the basis for noninvasive, fast, and accessible diagnostic imaging. This tool is increasingly used in skin cancer and inflammatory conditions as well as in cosmetic dermatology. This article reviews the basic principles of skin ultrasound and its applications in the different areas of dermatology.

Recent developments in the medical and surgical treatment of melanoma

Increasing knowledge of the biology of melanoma has led to significant advances in drug development to fight this disease. Surgery is the primary treatment for localized disease and is an integral part of management in patients with more advanced disease. The last decade has become the era of targeted therapy in melanoma and has revolutionized the treatment of this disease. Since 2011, 4 new agents have been approved for the treatment of patients with metastatic melanoma: ipilimumab, vemurafenib, dabrafenib, and trametinib. Several new agents are currently in phase 3 trials with hopes of even more agents being approved for this once "untreatable" disease. How to integrate surgical options with more effective systemic therapies has become a new challenge for physicians. This review will provide an update on current surgical options, highlight the pathway to the development of the newly approved agents, and further discuss new treatments that are on the horizon.

Fine-needle aspiration cytology for the diagnosis of metastatic melanoma: systematic review and meta-analysis

OBJECTIVES

To perform a thorough review and meta-analysis of studies that have shown non-image-guided fine-needle aspiration cytology (FNAC) to be highly sensitive and specific for assessing questionable metastatic melanoma to lymph nodes.

METHODS

MEDLINE and Scopus were searched for potentially relevant articles with a search string including the words "melanoma" and "fine needle." All relevant articles were screened by two authors (B.J.H. and R.L.S.). Full articles were screened for extractable data, and the data was pooled for analysis.

RESULTS

Of 978 unique studies found, 10 (5,518 cases) met our inclusion criteria. In a pooled analysis of palpation and ultrasound-guided fine-needle aspirations, the area under the receiver operating characteristic curve was 0.99 (95% confidence interval [CI], 0.99-1.00). The summary estimates for the sensitivity and specificity were 0.97 (95% CI, 0.95-0.98) and 0.98 (95% CI, 0.98-1.00), respectively.

CONCLUSIONS

With a sensitivity and specificity of 0.97 and 0.99, the overall diagnostic accuracy of FNAC for metastatic melanoma is quite high, and with a positive and negative likelihood ratio of 58 and 0.03, FNAC for metastatic melanoma should be the first-line option in a patient with a clinically suspected mass and a history of melanoma.

Acute toxoplasmosis mimicking melanoma metastases: review of conditions causing false-positive results on (18)F-FDG PET/CT

Invasive malignant melanoma is the most common fatal form of skin cancer. Fluorine-18-fluorodeoxyglucose positron emission tomography-computed tomography demonstrates a very high sensitivity and specificity for the detection of melanoma metastases. Here, we report an unusual case of toxoplasma lymphadenitis in a male adult patient mimicking a malignant cervical lymphadenopathy. Toxoplasmosis is a zoonosis caused by the intracellular parasite Toxoplasma gondii, which is usually asymptomatic in immunocompetent hosts.