TORONTO--Patients with high-risk melanoma may benefit from use of
whole-body 18F-fluorodeoxyglucose positron emission tomography
(FDG-PET) for primary staging, researchers from the University of
Frankfurt/Main reported at the 45th Annual Meeting of the Society of
Improved Diagnostic Accuracy
"We find an improved diagnostic accuracy using FDG-PET to assess
patients," said Dr. Andreas Hertel, Department of Nuclear
Medicine, University Hospital, Frankfurt. "The sensitivity and
specificity of PET is superior, particularly in high-risk patients
This prospective study included 100 patients with confirmed high-risk
malignant melanoma. They were evaluated using whole-body FDG-PET and
conventional diagnostic imaging (MRI of the brain; x-ray of the
chest; CT of the thorax, abdomen, and pelvis; ultrasound of the
abdomen; high-resolution lymph node sonography; and skeletal scintigraphy).
Fifty-two of the patients were studied at primary diagnosis of their
disease and 48 at follow-up with suspicion of recurrence. Every
identified lesion was confirmed by histology.
For the patients with a primary diagnosis, PET was 100% sensitive in
detecting metastases (see figure),
while conventional imaging did not identify any of the nine
metastatic lesions. In the patients with suspected recurrence, 121
lesions were detected, 111 (92%) by PET and 69 (57%) by conventional
imaging. The conventional methods did not identify all patients with
progression and detected significantly fewer metastases.
Results Depended on Site
Results also depended on specific sites (see table):
While PET yielded a higher sensitivity in detecting cervical
metastases (100% vs 66.6%) and abdominal metastases (100% vs 26.6%),
CT proved to be superior in detecting small lung metastases (87% vs 69.6%).
"We demonstrated that we can find very small lesions with a high
sensitivity and specificity compared to CT, especially in the primary
staging of high-risk patients," Dr. Hertel said. "We
believe that PET should replace CT as the front-line procedure in
Speaking at a press conference held in conjunction with the meeting,
lead author Richard P. Baum, MD, chair of the Bad Berka PET Center,
said: "If we detect lesions with FDG-PET and plan to operate,
then we need CT and/or MRI for anatomic information and surgical
planning, but we dont need those tests for staging a patient
with malignant melanoma as the front-line procedure."
Dr. Baum also pointed out that use of PET can save considerable time.
"We can do a whole-body FDG-PET scan in one hour," he said,
"compared to multiple days in the hospital for a standard