Routine FDG PET-CT in patients with a high-risk localized melanoma has a high predictive positive value for nodal disease and high negative predictive value for the presence of distant metastases

Diagnostic Performance of [18F]F-FDG Positron Emission Tomography (PET) in Non-Ophthalmic Malignant Melanoma: A Systematic Review and Meta-Analysis of More Than 10,000 Melanoma Patients

We described the diagnostic performance of [18F]F-FDG-PET in malignant melanoma by conducting a comprehensive systematic review and meta-analysis of the existing literature. The study was designed following PRISMA-DTA. Original articles with adequate crude data for meta-analytic calculations that evaluated [18F]F-FDG-PET and compared it with a valid reference standard were considered eligible. The pooled measurements were calculated based on the data level (patient/lesion-based). Regarding sub-groups, diagnostic performances were calculated for local, regional and distant involvement. The bivariate model was employed to calculate sensitivity and specificity. The initial search resulted in 6678 studies. Finally, 100 entered the meta-analysis, containing 82 patient-based (10,403 patients) and 32 lesion-based (6188 lesions) datasets. At patient level, overall, [18F]F-FDG-PET had pooled sensitivity and specificity of 81% (95%CI: 73-87%) and 92% (95%CI: 90-94%), respectively. To detect regional lymph node metastasis, the pooled sensitivity and specificity were 56% (95%CI: 40-72%) and 97% (95%CI: 94-99%), respectively. To detect distant metastasis, they were 88% (95%CI: 81-93%) and 94% (95%CI: 91-96%), respectively. At lesion level, [18F]F-FDG-PET had a pooled sensitivity and specificity of 70% (95%CI: 57-80%) and 94% (95%CI: 88-97%), respectively. Thus, [18F]F-FDG-PET is a valuable diagnostic modality for melanoma assessment. It was accurate in various clinical scenarios. However, despite its high specificity, it showed low sensitivity in detecting regional lymph node metastasis and could not replace lymph node biopsy.

Yield of baseline imaging for distant metastases in high-risk primary melanoma

BACKGROUND

The yield of baseline imaging in patients presenting with higher risk primary tumours, at least American Joint Committee on Cancer 8th edition stage IIC or III melanoma, is unclear.

METHODS

This retrospective study included patients referred to the Victorian Melanoma Service from January 2017 to April 2020, diagnosed with at least stage IIC or stage III melanoma. Patients with a T4b tumour and no sentinel lymph node biopsy were included as 'T4bNX'.

RESULTS

One hundred and sixty-four patients (median age 65 years) with baseline imaging (T4bNX: 19, IIC: 30, IIIA: 21, IIIB: 43, IIIC: 50, IIID: 1) were included. The majority were male (73%), and those with T4bNX melanoma tended to be older (median age 79 years). Distant metastases were detected in 21% (4/19) of T4bNX, 3% (1/30) of stage IIC, 0% (0/21) of stage IIIA, and 6% (6/94) of stages IIIB-D melanoma patients. All stage III patients with distant metastases had palpable lymphadenopathy a presentation. Two patients had brain metastases, both of whom had T4bNX melanoma and synchronous extra-cranial metastases.

CONCLUSIONS

Compared to stage IIC, baseline imaging detects higher rates of extra-cranial distant disease in stages IIIB-D and T4bNX melanoma. Intracranial imaging has greater yield in patients with distant extra-cranial disease.

Canadian Melanoma Conference Recommendations on High-Risk Melanoma Surveillance: A Report from the 14th Annual Canadian Melanoma Conference; Banff, Alberta; 20-22 February 2020

Introduction: There are a lack of established guidelines for the surveillance of high-risk cutaneous melanoma patients following initial therapy. We describe a novel approach to the development of a national expert recommendation statement on high-risk melanoma surveillance (HRS). Methods: A consensus-based, live, online voting process was undertaken at the 13th and 14th annual Canadian Melanoma Conferences (CMC) to collect expert opinions relating to “who, what, where, and when” HRS should be conducted. Initial opinions were gathered via audience participation software and used as the basis for a second iterative questionnaire distributed online to attendees from the 13th CMC and to identified melanoma specialists from across Canada. A third questionnaire was disseminated in a similar fashion to conduct a final vote on HRS that could be implemented. Results: The majority of respondents from the first two iterative surveys agreed on stages IIB to IV as high risk. Surveillance should be conducted by an appropriate specialist, irrespective of association to a cancer centre. Frequency and modality of surveillance favoured biannual visits and Positron Emission Tomography Computed Tomography (PET/CT) with brain magnetic resonance imaging (MRI) among the systemic imaging modalities available. No consensus was initially reached regarding the frequency of systemic imaging and ultrasound of nodal basins (US). The third iterative survey resolved major areas of disagreement. A 5-year surveillance schedule was voted on with 92% of conference members in agreement. Conclusion: This final recommendation was established following 92% overall agreement among the 2020 CMC attendees.

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.

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.

Diagnostic accuracy of (18)F-FDG-PET/CT in early and late stages of high-risk cutaneous malignant melanoma

BACKGROUND

The precise role of total body (18) F-fluorodeoxyglucose-positron emission tomography/computed tomography (PET/CT) in the clinical management of patients with cutaneous malignant melanoma (CMM) is not well established.

OBJECTIVE

The purpose of this study was to investigate the diagnostic accuracy of PET/CT in early- and late-stage patients with high-risk CMM.

METHODS

We retrospectively analysed various imaging, histopathological and clinical data from 97 patients also examined by PET/CT during a 5-year period (2007-2011). Three groups were assessed: stage I/II, resected stage III and unresectable stage III/stage IV.

RESULTS

The median follow-up time of living patients was 43.48 ± 19.67 (15-142) months. We observed a high diagnostic accuracy in all stages (91.3%, 92.5% and 96.2% respectively). PET/CT appeared to be reliable diagnostic tool even for the detection of small lymph node metastases. PET/CT was informative in 14 of 19 cases wherein another imaging examination provided inconclusive results regarding lesion dignity. However, PET/CT was less suitable for properly evaluating the dignity of a lung lesion. A true positive scan was twice as likely in clinically negative patients with resected stage III disease than in patients with stage I/II disease (35.9% and 14.5%, P = 0.007).

CONCLUSIONS

These results confirm that PET/CT is an important diagnostic tool in the management of patients with high-risk CMM, but it cannot replace the standard of care examinations. More accurate clinicopathological and timing criteria must be defined to best utilize the advantages of this imaging method.

Latissimus dorsi free flap reconstruction of major abdominal defect in treatment of giant Marjolin's ulcer: a short report focused on preoperative imaging

We present a case of a 56-year-old man with a giant carcinoma in the abdominal wall. Based on positron emission tomography/computed tomography (PET/CT) scan there were FDG-avid lymph nodes in the ipsilateral axillary and groin, suspicious for metastases. At contrast-enhanced CT the parietal peritoneum seemed free of tumor invasion, which was essential to radical surgery planning. The tumor was completely removed with clear margins of resection and no metastasis in the resected lymph nodes. The PET/CT scan was repeated after 4 months, showing no signs of recurrence.