PET/CT surveillance detects asymptomatic recurrences in stage IIIB and IIIC melanoma patients: a prospective cohort study

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.

Recurrence Patterns for Regionally Metastatic Melanoma Treated in the Era of Adjuvant Therapy: A Systematic Review and Meta-Analysis

BACKGROUND

The purpose of this systematic review was to examine the timing and patterns of recurrence for patients with regionally metastatic melanoma on the basis of nodal management and receipt of adjuvant therapy.

METHODS

We identified randomized controlled trials and non-randomized studies published between 2010 and 2020 that reported timing and/or patterns of recurrence. We evaluated recurrence-free survival (RFS), location of recurrence, and surveillance strategy on the basis of receipt of adjuvant systemic therapy and nodal management with observation versus completion dissection. We compared differences in patterns of recurrence across studies using RevMan. RFS was evaluated graphically using point estimates and confidence intervals.

RESULTS

Among the 19 publications, there was wide variation in study populations, imaging surveillance regimens, and format of recurrence reporting. Patterns of disease recurrence did not differ between adjuvant and placebo/observation groups. A total of 11 studies reported RFS at variable time intervals, which ranged in adjuvant therapy groups (38-88% at 1 year, 29-67% at 2 years, 33-58% at 3 years, and 34-53% at 5 years) and placebo/observation groups (47-63% at 1 year, 39-47% at 2 years, 33-68% at 3 years, and 57% at 5 years). Anti-PD-1 immune therapy and BRAF/MEK inhibitor therapy were superior to placebo at year 1.

DISCUSSION

We found that adjuvant treatment improved RFS but did not alter the patterns of disease recurrence compared with patients managed without adjuvant systemic treatment. Future studies should separately report sites of disease recurrence on the basis of specific adjuvant systemic treatment and surveillance practices to better advise patients about their patterns and risk of recurrence.

Precision Nuclear Medicine: The Evolving Role of PET in Melanoma

The clinical management of melanoma patients has been rapidly evolving with the introduction of new targeted immuno-oncology (IO) therapeutics. The current diagnostic paradigms for melanoma patients begins with the histopathologic confirmation of melanoma, initial staging of disease burden with imaging and surgical approaches, treatment monitoring during systemic cytotoxic chemotherapy or IO therapeutics, restaging after completion of adjuvant systemic, surgical, and/or external radiation therapy, and the detection of recurrent malignancy/metastatic disease following therapy. New and evolving imaging approaches with positron-emission tomography (PET) imaging technologies, imaging methodologies, image reconstruction, and image analytics will likely continue to improve tumor detection, tumor characterization, and diagnostic confidence, enabling novel precision nuclear medicine practices for managing melanoma patients. This review will examine current concepts and challenges with existing PET imaging diagnostics for melanoma patients and introduce exciting new opportunities for PET in the current era of IO therapeutics.

Routine PET-CT scans provide early and accurate recurrence detection in asymptomatic stage IIB-III melanoma patients

INTRODUCTION

The use of routine imaging with 18F-FDG PET-CT (PET-CT) in melanoma surveillance is debated and evidence of its diagnostic value and yield in asymptomatic patients is limited. Denmark introduced nationwide routine surveillance with PET-CT in high-risk patients in 2016. The aim of this study was to examine the sensitivity, specificity, negative and positive predictive values, numbers-needed-to-scan and clinical impact of routine PET-CT in the surveillance of asymptomatic stage IIB-III melanoma patients.

MATERIALS AND METHODS

Data was retrieved from the population-based Danish Melanoma Database and patient records. All patients diagnosed with stage IIB-III melanoma at two University Hospitals in 2016 and 2017 were included. Patients underwent surveillance with clinical examinations and PET-CT scans at 6, 12, 24 and 36 months.

RESULTS

In 138 patients, 243 routine PET-CTs were performed within a median follow-up time of 17.7 months. Routine PET-CT detected recurrence at least once in 25 patients (18.1%), including distant recurrence in 19 patients (13.8%). Stage IIB patients had the lowest recurrence rate (11.1%). Numbers-needed-to-scan to detect one distant recurrence was 12.8 patients and median time-to-recurrence was 6.8 months. Sensitivity was 100%, specificity was 94.7% and negative and positive predictive values were 100% and 74.4%, respectively. False positive findings prompted 22 additional investigations (of which ten invasive) in 17 patients (12.3%).

CONCLUSION

Routine PET-CT has a high sensitivity and specificity when used in high-risk melanoma surveillance. Time-to-recurrence and stage-specific recurrence rates indicate high gain of early routine imaging at six months especially for stage IIC and III patients.

The use of FDG-PET/CT to detect early recurrence after resection of high-risk stage III melanoma

BACKGROUND

The role of surveillance imaging in high-risk stage III melanoma patients after complete surgical resection remains controversial, and with the advent of adjuvant therapy, it may also be expanded. Therefore, we evaluated two fluorine-18 fluorodeoxyglucose-positron emission tomography/computed tomography (FDG-PET/CT) protocols in two cohorts.

METHODS

Cohort 1 (n = 35) focused on surveillance in asymptomatic patients (before approval and reimbursement of adjuvant therapy) and was assigned to 5x FDG-PET/CT's after surgery: one every 6 months for 2 years, with one final scan after 3 years. Cohort 2 (n = 42) was assigned to one screening FDG-PET/CT, which took place in between surgery and the start of adjuvant treatment.

RESULTS

In cohort 1 (median follow-up: 33 months), 12 patients (34.3%) developed recurrence detected by FDG-PET/CT, of which 7 (20.0%) were detected with the first scan. Sensitivity and specificity were 92.3% and 100%, respectively. In cohort 2, recurrence was suspected on nine scans (21.4%) and four (9.5%) were true positive. The number of scans needed to find one asymptomatic recurrence were 8.8 and 10.5 in cohort 1 and 2, respectively.

CONCLUSIONS

FDG-PET/CT is a valuable imaging tool to detect recurrence in stage III melanoma, even shortly after surgery. A surveillance FDG-PET/CT protocol after surgery or a screening PET/CT before adjuvant therapy should be considered.

18F-fluorodeoxyglucose Positron Emission Tomography/Computed Tomography for Assessing Tumor Response to Immunotherapy in Solid Tumors: Melanoma and Beyond

The complexity of the immune response and diversity of targets challenges conventional conceptual frameworks used in selecting and monitoring treatment with immune check-point inhibitors. The limitations of anatomic imaging in assessing response have been recognized. Varying patterns of response have been recognized. These patterns have different implications for the continuation and duration of therapy. Evidence supporting the role of ¹⁸F-fluorodeoxyglucose Positron Emission Tomography/Computed Tomography as a prognostic biomarker and in characterizing response is presented. An added benefit of this approach is the ability to detect immune-related inflammatory reactions, often in advance of severe or life-threatening clinical manifestations.

Diagnostic value of surveillance 18F-fluorodeoxyglucose PET/CT for detecting recurrent esophageal carcinoma after curative treatment

PURPOSE

Esophageal carcinoma recurs within two years in approximately half of patients who receive curative treatment and is associated with poor survival. While ¹⁸F-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) is a reliable method of detecting recurrent esophageal carcinoma, in most previous studies FDG PET/CT scans were performed when recurrence was suspected. The aim of this study was to evaluate FDG PET/CT as a surveillance modality to detect recurrence of esophageal carcinoma after curative treatment where clinical indications of recurrent disease are absent.

METHODS

A total of 782 consecutive FDG PET/CT studies from 375 patients with esophageal carcinoma after definitive treatment were reviewed. Abnormal lesions suggestive of recurrence on PET/CT scans were then evaluated. Recurrence was determined by pathologic confirmation or other clinical evidence within two months of the scan. If no clinical evidence for recurrence was found at least 6 months after the scan, the case was considered a true negative for recurrence.

RESULTS

The diagnostic sensitivity and specificity of PET/CT for detecting recurrent esophageal carcinomas were 100% (64/64) and 94.0% (675/718), respectively. There were no significant differences in the diagnostic performance of PET/CT for detecting recurrence according to initial stage or time between PET/CT and curative treatments. Unexpected second primary cancers were detected by FDG PET/CT in seven patients.

CONCLUSIONS

Surveillance FDG PET/CT is a useful imaging tool for detection of early recurrence or clinically unsuspected early second primary cancer in patients with curatively treated esophageal carcinoma but without clinical suspicion of recurrence.

Early Recurrence in Completely Resected IIIB and IIIC Melanoma Warrants Restaging Prior to Adjuvant Therapy

Purpose

To evaluate the results of restaging completely resected stage IIIB/C melanoma prior to start of adjuvant therapy.

Patients and Methods

One hundred twenty patients with stage IIIB or IIIC (AJCC 2009) melanoma who underwent complete surgical resection were screened for inclusion in our trial investigating adjuvant dendritic cell therapy (NCT02993315). All patients underwent imaging to exclude local relapse or metastasis before entering the trial. The frequency of recurrent disease within 12 weeks after resection and the method of detection were investigated.

Results

Sixty-nine (58%) stage IIIB and 51 (43%) stage IIIC melanoma patients were screened. Median age was 54 (range 27–79) years. Twenty-two (18%) of 120 patients with completely resected stage IIIB/C melanoma had evidence of early recurrent disease, despite exclusion thereof by prior imaging. Median interval between resection and detection of relapse was 7.4 (range 4.3–10.7) weeks. Recurrence was asymptomatic in 17 (77%) patients, but metastasis was noticed by the patient or physician in 5 (23%). Eight patients with local relapse received local treatment with curative intent, and one was treated with systemic therapy. The remaining patients had distant metastasis, 1 of whom underwent resection of a solitary liver metastasis while 12 patients received systemic treatment.

Conclusions

Patients with completely resected stage IIIB/C melanoma have high risk of early recurrence before start of adjuvant therapy. Restaging should be considered for high-risk melanoma patients before start of adjuvant therapy.

Surveillance imaging for metastasis in high-risk melanoma: importance in individualized patient care and survivorship

Most patients newly diagnosed with melanoma have early-stage disease considered of good prognosis. However, with a risk of recurrence, appropriate follow-up may include surveillance imaging for early relapse detection. Previously, surveillance imaging to detect recurrences was considered unjustified, given the lack of effective treatments. Now, systemic therapies have improved, and patients with low tumor burden may derive benefit from surveillance imaging. Despite this, controversy exists regarding the role of surveillance imaging in early-stage melanoma survivorship, in part reflected by the lack of consensus on specific imaging protocols and broad guidelines. This review discusses published evidence on surveillance imaging to detect metastasis in high-risk melanoma, the need for early recurrence detection and implications for value-based clinical decision-making, survivorship care and multidisciplinary patient management.