[Whole-body staging of malignant melanoma: advantages, limitations and current importance of PET-CT, whole-body MRI and PET-MRI]

Evidence of 18 F-FDG Utility in Rare Case of Metastatic Anal Melanoma With Prolonged Survival

ABSTRACT

A 43-year-old woman presented with an anorectal mass at which time excision was performed, and biopsy revealed anorectal mucosal melanoma (AM), anal subtype. Postexcision, 18 F-FDG PET/CT identified residual melanoma, confirmed on biopsy. Recurrence was monitored every 3 months using 18 F-FDG, which identified a perirectal lymph node 2.5 years later positive for metastatic melanoma. Given the rarity of AM and often delayed diagnosis, patients often present with metastases, resulting in poor prognosis. This unique case of metastatic AM with prolonged survival of 7 years to date supports the implementation of 18 F-FDG in the diagnostics and monitoring of AM.

Positron emission tomography-computed tomography vs. brain magnetic resonance imaging for the detection of cerebral metastases of melanoma: a 5-year retrospective study

BACKGROUND

Patients with melanoma present a high risk of developing extracutaneous metastases. Positron emission tomography--computed tomography (PET-CT) is one of the preferred examinations for the staging of oncological patients. It is not the method of choice to detect brain metastases, but this technique has shown significant improvement and allows the detection of some of them. However, it is unclear how it performs compared with magnetic resonance imaging (MRI), the current gold standard for diagnosing brain metastases.

OBJECTIVES

To compare the accuracy of PET-CT and cerebral MRI to detect brain metastases in patients with melanoma.

METHODS

We retrospectively included all patients diagnosed with melanoma stage IIC-IV (American Joint Committee on Cancer 8th Edition, 2017) who presented at the skin tumour board of the University Hospital of Bern between January 2018 and December 2022. All radiological reports extracted from the patient management system were analysed to assess discrepancy between the visibility of brain metastases on PET-CT and brain MRI.

RESULTS

In this study including 393 patients, brain MRI demonstrated significantly better performance than PET-CT in detecting brain metastases. In 47 patients, cerebral metastases were detected completely, detected partially, or not detected by PET-CT in 2 (4%), 15 (32%) and 30 (64%), respectively.

CONCLUSIONS

Despite the increasing performance of PET-CT, this study highlights the crucial role of brain MRI, which remains the gold standard to detect cerebral metastases. Brain MRI should be performed in patients with high-risk melanoma from stage IIC to exclude brain metastases.

Comparing the diagnostic efficacy of [18F]FDG PET/CT and [18F]FDG PET/MRI for detecting bone metastases in breast cancer: a meta-analysis

BACKGROUND

This meta-analysis aimed to evaluate the comparative diagnostic efficacy of [18F]FDG PET/CT and [18F] FDG PET/MRI in detecting bone metastases in breast cancer patients.

METHODS

An extensive search was conducted in the PubMed, Embase, Web of Science, and Cochrane Library databases to identify available publications up to February 2023. Studies were included if they evaluated the diagnostic efficacy of [18F]FDG PET/CT and [18F]FDG PET/MRI in patients with breast cancer bone metastases. Sensitivity and specificity were assessed using the DerSimonian and Laird method, followed by transformation via the Freeman-Tukey double inverse sine transformation.

RESULTS

16 articles (including 4 head-to-head comparison articles) involving 1,261 patients were included in the meta-analysis. The overall sensitivity of [18F]FDG PET/CT in patient-based analysis, lesion-based analysis, and head-to-head comparison were 0.73, 0.89, and 0.87, respectively, while the overall sensitivity of [18F]FDG PET/MRI were 0.99, 0.99, and 0.99. The results indicated that [18F]FDG PET/MRI appears to a higher sensitivity in comparison to [18F]FDG PET/CT(all P < 0.05). In contrast, the overall specificity of [18F]FDG PET/CT in patient-based analysis, lesion-based analysis, and head-to-head comparison were 1.00, 0.99, and 1.00, respectively, while the overall specificity of [18F]FDG PET/MRI were 1.00, 0.99, and 0.98. These results suggested that [18F]FDG PET/CT has a similar level of specificity compared to [18F]FDG PET/MRI.

CONCLUSIONS

Our meta-analysis indicates that [18F]FDG PET/MRI demonstrates superior sensitivity and similar specificity to [18F]FDG PET/CT in detecting bone metastases in breast cancer patients. Further prospective research is required to confirm these findings and assess the clinical application of these techniques.

Whole-Body Magnetic Resonance Imaging (MRI) for Staging Melanoma Patients in Direct Comparison to Computed Tomography (CT): Results from a Prospective Positron Emission Tomography (PET)/CT and PET/MRI Study

PURPOSE

The consideration of radiation exposure is becoming more important in metastatic melanoma due to improved prognoses. The aim of this prospective study was to investigate the diagnostic performance of whole-body (WB) magnetic resonance imaging (MRI) in comparison to computed tomography (CT) with ¹⁸F-FDG positron emission tomography (PET)/CT and ¹⁸F-PET/MRI together with a follow-up as the reference standard.

METHODS

Between April 2014 and April 2018, a total of 57 patients (25 females, mean age of 64 ± 12 years) underwent WB-PET/CT and WB-PET/MRI on the same day. The CT and MRI scans were independently evaluated by two radiologists who were blinded to the patients' information. The reference standard was evaluated by two nuclear medicine specialists. The findings were categorized into different regions: lymph nodes/soft tissue (I), lungs (II), abdomen/pelvis (III), and bone (IV). A comparative analysis was conducted for all the documented findings. Inter-reader reliability was assessed using Bland-Altman procedures, and McNemar's test was utilized to determine the differences between the readers and the methods.

RESULTS

Out of the 57 patients, 50 were diagnosed with metastases in two or more regions, with the majority being found in region I. The accuracies of CT and MRI did not show significant differences, except in region II where CT detected more metastases compared to MRI (0.90 vs. 0.68, p = 0.008). On the other hand, MRI had a higher detection rate in region IV compared to CT (0.89 vs. 0.61, p > 0.05). The level of agreement between the readers varied depending on the number of metastases and the specific region, with the highest agreement observed in region III and the lowest observed in region I.

CONCLUSIONS

In patients with advanced melanoma, WB-MRI has the potential to serve as an alternative to CT with comparable diagnostic accuracy and confidence across most regions. The observed limited sensitivity for the detection of pulmonary lesions might be improved through dedicated lung imaging sequences.

Noncontrast-enhanced 3-Tesla MRI using surface coil as a complementary test for assessment of distribution and depth of locoregional cutaneous metastases of malignant melanoma

Locoregional and distant metastases account for most cases of morbidity and mortality associated with melanoma. In addition, local recurrences of melanoma might be the onset of disseminated disease. Therefore, precise diagnosis and therapy are warranted to minimize morbidity and increase survival in a subset of patients. However, the correct distribution of the metastatic lesions on the skin is often difficult to estimate. We present the application of noncontrast-enhanced 3-Tesla MRI using surface coil to detect locoregional cutaneous metastases of malignant melanoma on the basis of the topographic assessment of skin lesions. Furthermore, in a systematic review, we summarize the current knowledge about application of MRI in assessment of location, distribution, and depth of cutaneous primary malignant melanoma. MRI might be applied to evaluate the location, distribution, size, and depth of the locoregional cutaneous metastasis of malignant melanoma to identify the optimal cost-effective treatment strategies and monitor their effects.

Bone Metastases Are Measurable: The Role of Whole-Body MRI and Positron Emission Tomography

Metastatic tumor deposits in bone marrow elicit differential bone responses that vary with the type of malignancy. This results in either sclerotic, lytic, or mixed bone lesions, which can change in morphology due to treatment effects and/or secondary bone remodeling. Hence, morphological imaging is regarded unsuitable for response assessment of bone metastases and in the current Response Evaluation Criteria In Solid Tumors 1.1 (RECIST1.1) guideline bone metastases are deemed unmeasurable. Nevertheless, the advent of functional and molecular imaging modalities such as whole-body magnetic resonance imaging (WB-MRI) and positron emission tomography (PET) has improved the ability for follow-up of bone metastases, regardless of their morphology. Both these modalities not only have improved sensitivity for visual detection of bone lesions, but also allow for objective measurements of bone lesion characteristics. WB-MRI provides a global assessment of skeletal metastases and for a one-step "all-organ" approach of metastatic disease. Novel MRI techniques include diffusion-weighted imaging (DWI) targeting highly cellular lesions, dynamic contrast-enhanced MRI (DCE-MRI) for quantitative assessment of bone lesion vascularization, and multiparametric MRI (mpMRI) combining anatomical and functional sequences. Recommendations for a homogenization of MRI image acquisitions and generalizable response criteria have been developed. For PET, many metabolic and molecular radiotracers are available, some targeting tumor characteristics not confined to cancer type (e.g. 18F-FDG) while other targeted radiotracers target specific molecular characteristics, such as prostate specific membrane antigen (PSMA) ligands for prostate cancer. Supporting data on quantitative PET analysis regarding repeatability, reproducibility, and harmonization of PET/CT system performance is available. Bone metastases detected on PET and MRI can be quantitatively assessed using validated methodologies, both on a whole-body and individual lesion basis. Both have the advantage of covering not only bone lesions but visceral and nodal lesions as well. Hybrid imaging, combining PET with MRI, may provide complementary parameters on the morphologic, functional, metabolic and molecular level of bone metastases in one examination. For clinical implementation of measuring bone metastases in response assessment using WB-MRI and PET, current RECIST1.1 guidelines need to be adapted. This review summarizes available data and insights into imaging of bone metastases using MRI and PET.

PET/CT in malignant melanoma: a two-tiered healthcare system? Updated healthcare situation regarding initial staging of malignant melanoma with PET/CT

BACKGROUND

Patients with stage IIC malignant melanoma are recommended to undergo cross-sectional imaging for initial staging. PET/CT is superior to other methods regarding its diagnostic accuracy of the tumor spread in stage III. So far there is no meaningful data on the nationwide availability, usage and cost recovery of this imaging technique.

PATIENTS AND METHODS

Questionnaires on the healthcare situation in 2018 were sent to all German dermatology clinics and PET/CT centers in March and April 2019.

RESULTS

61.2 % of the dermatology clinics (71/115) and 48.2 % of the PET/CT centers (77/160) took part in the survey. A total of 22,645 patients with malignant melanoma were seen in these clinics in 2018. 16.8 % of the patients with stage IIC melanoma received a PET/CT for primary staging. The costs of this examination were covered for all statutory and privately insured patients in 40 % and 68 % of dermatology clinics (20/50 and 34/50), respectively. 68.0 % (34/50) of all dermatology clinics reported relevant changes of treatment according to PET/CT findings. Long examination periods by the health insurance companies and the time required to submit the application were the most common reasons for dermatology clinics to reject a request for PET/CT. Relevant incidental findings were reported in 90.2 % (47/51) of all PET/CT centers.

CONCLUSIONS

There are clear differences in the nationwide availability and cost coverage of PET/CT in primary staging for stage IIC melanoma. For these reasons, a two-tiered healthcare system may be assumed.

Influence of 18F-FDG PET/CT on clinical management and outcome in patients with advanced melanoma not primarily selected for surgery based on a linked evidence approach

PURPOSE

To evaluate the clinical benefit of positron emission tomography (PET)/computed tomography (CT) in patients with advanced melanoma, primarily not selected for surgery based on management changes and survival data using the linked evidence approach (LEA).

METHODS

A total of 201 ¹⁸F-FDG PET/CT examinations (n = 33, stage III and n = 168, stage IV) in 119 melanoma patients, primarily not scheduled for surgery, were analysed regarding their impact on clinical management. Patients were selected from a prospective oncological PET/CT registry. The three PET/CT indication groups included unclear lesions in conventional imaging (n = 8), routine follow-up after multiple surgeries (n = 115) and therapy response evaluation of systemic therapy (n = 78). PET/CT-induced management changes were categorized either as major (change from follow-up to surgical or systemic treatment or vice versa, change from surgery to systemic therapy or vice versa) or minor (modifications in systemic therapy). The expected benefit of changes was determined via the linked evidence approach (LEA) connecting registry data, outcome data including overall survival and evidence of diagnostic accuracy of PET/CT based on existing literature.

RESULTS

Related to the total study cohort, a change of management after PET/CT was observed in 48% of scans, including 10% minor and 38% major changes. Major changes involved a shift either from follow-up (33/201) or therapy pause (7/201) to systemic therapy, to surgical or other local therapy (26/201) and BSC (2/201). Nine out of 201 cases resulted in treatment pause of systemic therapy. We could confirm the prognostic value of PET/CT-based management by observing a 5-year survival rate more than roughly doubled in patients followed up after tumour exclusion or under local therapy compared with patients under systemic therapy. We could argue for a patient benefit from PET/CT-based management changes using results on accuracy and therapeutic effects from the literature.

CONCLUSION

The use of PET/CT in advanced melanoma patients, primarily not considered for surgery, resulted in frequent changes of management associated with a relevant expected clinical benefit especially in patients classified by PET/CT as tumour-free or eligible for radical surgery.

Whole-Body MR Imaging: The Novel, "Intrinsically Hybrid," Approach to Metastases, Myeloma, Lymphoma, in Bones and Beyond

Whole-body MR imaging (WB-MR imaging) has become a modality of choice for detecting bone metastases in multiple cancers, and bone marrow involvement by multiple myeloma or lymphoma. Combination of anatomic and functional sequences imparts an inherently hybrid dimension to this nonirradiating tool and extends the screening of malignancies outside the skeleton. WB-MR imaging outperforms bone scintigraphy and CT and offers an alternative to PET in many tumors by time of lesion detection and assessment of treatment response. Much work has been done to standardize procedures, optimize sequences, validate indications, confirm preliminary research into new applications, rendering clinical application more user-friendly.

Whole-Body Magnetic Resonance Imaging in the Oncology Setting: An Overview and Update on Recent Advances

Whole-body magnetic resonance imaging is becoming an important tool in oncology as a nonirradiating imaging technique since recent technological advances allowed the incorporation of high-quality imaging in an adequate time. Moreover, the noninjection of radioisotope/intravenous contrast, low cost compared with traditional nuclear medicine techniques, and fast acquisition times are another distinct feature. Thus, the purpose of this article is to review the whole-body magnetic resonance imaging protocol and its main applications in the oncology setting.

Dual-energy CT of liver metastases in patients with uveal melanoma

Objective

To investigate the value of different kVp images of dual-energy CT (DECT) for the detection of liver metastases.

Methods

20 Patients with uveal melanoma were investigated with DECT of the liver. In each patient contrast-enhanced DECT imaging with arterial delay was performed. Number and size of metastases were documented on arterial phase 80-kVp images, virtual 120-kVp images and following angiographic images (DSA) as part of hepatic chemoperfusion. Attenuation of metastases and several anatomic regions, subjective (image noise, image quality) and objective (SNR, CNR) parameters were documented.

Results

The mean number of liver metastases detected was significant higher on 80-kVp images than on virtual 120-kVp/DSA images (5.6 ± 2.1 vs. 4.1 ± 1.8/4.3 ± 1.6); (p < 0.001). All lesions sizes were significant better detected with 80 kVp images than with virtual 120 kVp and DSA-Images (80 kVp vs. 120 kVp: <10 mm: 34 vs. 19, p < 0.05; 10–20 mm:, 33 vs. 25, p < 0.05; >20 mm: 56 vs. 42, p < 0.05/80 kVp vs. DSA: <10 mm: 34 vs. 18 p < 0.05; 10–20 mm: 33 vs. 24, p < 0.05; >20 mm: 56 vs. 41, p < 0.05). Number of detected small lesions <10 mm with 120 kVp compared to DSA-images were significant higher (19 vs. 13; p < 0.05), lesions 10–20 mm and >20 mm were measured statistically equally. Noise, SNR and CNR of 80 kVp images were higher compared to 120 kVp images. Image quality of 120 kVp images was higher compared to 80 kVp images.

Conclusion

Low-kVp images of DECT datasets are more sensitive in detecting liver metastases of patients with uveal melanoma than virtual 120 kVp- and DSA images.

Anorectal malignant melanoma: curative abdominoperineal resection: patient selection with 18F-FDG-PET/CT

Background

Anorectal malignant melanomas (ARMM) are rare tumors, characterized by an early lymphatic spread and distant metastasis, resulting in an extremely poor overall survival. The objective of this study was to determine the pattern of regional lymph node metastasis (LNM) by computed tomography (CT) and 18F-FDG-PET/CT in patients undergoing abdominoperineal resection (APR) and its impact on oncologic outcome.

Methods

A retrospective analysis of six consecutive patients who underwent APR due to primary ARMM was performed. Patients were staged by CT and PET/CT.

Results

Four out of six patients had preoperative LNM involvement (two patients inguinal and perirectal, one iliacal, one perirectal), with two of them presenting with distant metastases additionally. Inguinal/iliacal LNM in two patients as well as liver metastasis in one patient was seen in PET/CT and missed by CT. The three patients with initial inguinal/iliacal LNM died during the observation period (overall survival: 10 (6–18) months). The three patients without inguinal/iliacal LNM involvement are currently alive, one patient showing a slowly progressive disease since 5 years, and two patients are tumor-free since 8.5 and 1.5 years (the patients had initial perirectal LNM).

Conclusions

In ARMM, PET/CT is superior to CT in detection of LNM and distant metastasis. APR is possibly a curative approach if the PET/CT shows exclusively perirectal LNM despite locally advanced tumor growth.

Influence of (18)F-FDG PET/CT on therapy management in patients with stage III/IV malignant melanoma

PURPOSE

To evaluate the influence of (18)F-FDG PET/CT in comparison to CT alone on treatment decisions in patients with advanced melanoma and to analyse the 5-year survival data in comparison to literature data.

METHODS

Therapy management in 64 consecutive patients (primary staging n = 52; surveillance n = 12) with stage III/IV melanoma who underwent (18)F-FDG PET/CT between 2004 and 2005 in our department was retrospectively analysed. Treatment decisions were made by two dermatooncologists for each patient twice, first based on the CT results and then based on the PET/CT results. Therapy changes based on the PET/CT results were classified as "major" (e.g. change from metastasectomy to systemic therapy) or "minor" (e.g. change from first to second line chemotherapy). The 5-year survival data of different patient cohorts were calculated.

RESULTS

In the 52 patients in the primary staging group, the results of (18)F-FDG PET/CT led to therapy change in 59% and a major therapy change in 52%. (18)F-FDG PET/CT led to the avoidance of futile operations in 13 patients with suspicious lesions on CT that were deemed nontumorous on PET/CT. In the 12 patients in the surveillance group, the results of (18)F-FDG PET/CT led to therapy change in 33% and a major change in 17%. The 5-year survival rates were 30% in the entire cohort, 34% in the primary staging group, and 17% in the surveillance group. A significant overall survival benefit was observed in patients in whom (18)F-FDG PET/CT excluded metastases or in whom metastases could be completely removed compared with patients who were not eligible for surgery (41% vs. 10%).

CONCLUSION

Primary staging of patients with stage III/IV melanoma should be performed with (18)F-FDG PET/CT, leading to higher diagnostic accuracy and enabling individualized therapeutic management, especially optimal patient selection for metastasectomy. This strategy may extend long-term survival even in patients with advanced disease.

Primary Malignant Melanoma of the Esophagus: A Case Report and Review of the Literature

BACKGROUND Primary malignant melanoma of the esophagus (PMME) is a rare cancer with a poor prognosis. It is often difficult to differentiate from non-epithelial malignant tumors, and immunohistochemical staining may be needed to diagnose the condition. The mainstay of treatment is usually surgical with curative or palliative intent, since radio- and chemotherapy do not really improve the outcome. The average survival rate after surgery is 34.5 months. At the time of diagnosis, 40-80% of cases have local regional lymph node metastases. CASE REPORT The case of a 67-year-old male patient with PMME is reported. He presented with progressive dysphagia. A computerized tomography was performed in which a polypoid mass was observed in the distal esophagus. It was originally suspected to be an adenocarcinoma, but was subsequently correctly diagnosed by immunohistochemical staining with HMB-45 antibody and by the presence of S-100 protein. A subtotal esophagectomy was performed. CONCLUSIONS Very few cases of PMME have been reported in the literature and there is only limited clinical experience with this disease. Therefore, it is very difficult to establish clear criteria for clinical recognition of this type of melanoma. Early histopathological confirmation of the character is essential for further treatment in case of confirmation of malignancy.