TORONTO--Therapeutic strategy in patients with head and neck cancer
is sometimes based on the staging of regional lymph nodes. However,
standard imaging techniques such as computed tomography (CT) and
magnetic resonance imaging (MRI) cannot differentiate between
inflammation and metastasis in an enlarged lymph node and may not
discover distant disease.
"Correct lymph node staging in squamous cell carcinoma is of
most importance in the selection of adequate treatment," Roland
Lietzenmayer, MD, said at the Society of Nuclear Medicine meeting.
"Currently, lymph node staging of the head and neck area with CT
and MRI lacks sensitivity and specificity to tumor infiltration. In
addition, tumor cells may also have infiltrated normal-sized lymph
nodes, which would not be suspected with conventional imaging techniques."
Dr. Lietzenmayer presented data from a study headed by Dr. Marcus
Müller-Berg and performed at Eberhard-Karls-University,
To evaluate the sensitivity of whole-body
fluorine-18-fluorodeoxyglucose positron emission tomography (FDG-PET)
in lymph node staging, 29 patients with suspected squamous cell
carcinoma were evaluated with FDG-PET, CT, and MRI within 10 to 14
days before therapy.
PET imaging detected all
malignant regions via increased focal FDG uptake, for a sensitivity
of 100%. Sensitivity with CT was 71% and with MRI, 94%. PET also had
higher specificity (97% vs 50% for CT and 58% for MRI). The positive
predictive value for PET was 65% vs 27% and 35% for CT and MRI,
respectively. Negative predictive value was 100% for PET, 87% for CT,
and 98% for MRI.
"Our data indicate that FDG-PET is highly reliable in the
preoperative staging of squamous cell carcinoma of the head and neck,
and should be performed routinely in these patients," Dr.
Lietzenmayer said. He added that if the high negative predictive
value seen with PET is confirmed, the technique could potentially be
used to individualize surgical treatment.
Also, whole-body FDG-PET imaging might replace other diagnostic
procedures, for example, endoscopy to exclude distant metastases or
second malignancies. However, he said, CT and MRI scans will still be
necessary to provide anatomic information for the surgeons.