PET vs sentinel lymph node biopsy for staging melanoma: a patient intervention, comparison, outcome analysis
Robert H El-Maraghi1, Ania Z Kielar
1Department of Oncology, The Royal Victoria Hospital, Barrie, Ontario, Canada.
Background:
Sentinel lymph node biopsy (SLNB) is the gold standard to assess local lymph nodes in patients with melanoma. Positron emission tomography (PET) has been investigated as a noninvasive alternative to SLNB.
Methods:
A systematic literature review was conducted to evaluate PET and PET/computed tomography (CT) compared with SLNB for staging local lymph nodes in patients with intermediate-risk melanoma using the patient, intervention, comparison, outcome (PICO) search strategy. The PubMed, Medline, CancerLit, and Cochrane Library databases were searched for relevant published materials. Guidelines of the American Society of Clinical Oncology (ASCO), and Cancer Care Ontario (CCO) were reviewed, as was the clinical resource, UpToDate. Studies were classified on the basis of levels of evidence delineated by the Oxford Centre for Evidence-Based Medicine.
Results:
The PICO search criteria identified 20 studies. There was no level 1 evidence. There were 7 level 2b articles. One review article was consecutive and thus classified as level 3a evidence. Three review articles were retrieved and categorized as level 3b. Three single-center studies were classified as level 3b, and another 3 were classified as level 4. There were two published letters, considered expert opinion and thus classified as level 5 evidence. All identified papers favored SLNB over PET or PET/CT for identifying occult locoregional lymph node metastases.
Conclusion:
Despite a lack of high-level evidence, the studies concluded that SLNB is superior to PET for local lymph node staging in patients with intermediate-risk melanoma. National guidelines confirmed these conclusions. The likelihood of PET/CT identifying distant metastases in this patient population is equally low because of the small risk for having distant metastases at diagnosis. Further study is required, including larger multicenter prospective trials.
