• 4/27/2006
  • New York, NY
  • Heiko Schöder et al.
  • Journal of Nuclear Medicine Vol. 47 No. 5 755-762

Introduction:
18F-FDG PET has a high accuracy in staging head and neck cancer, but its role in patients with clinically and radiographically negative necks (N0) is less clear. In particular, the value of combined PET/CT has not been determined in this group of patients.

Methods:
In a prospective study, 31 patients with oral cancer and no evidence of lymph node metastases by clinical examination or CT/MRI underwent 18F-FDG PET/CT before elective neck dissection. PET/CT findings were recorded by neck side (left or right) and lymph node level. PET/CT findings were compared with histopathology of dissected nodes, which was the standard of reference.

Results:
Elective neck dissections (26 unilateral, 5 bilateral; a total of 36 neck sides), involving 142 nodal levels, were performed. Only 13 of 765 dissected lymph nodes harbored metastases. Histopathology revealed nodal metastases in 9 of 36 neck sides and 9 of 142 nodal levels.
PET was TP in 6 nodal levels (6 neck sides), false-negative in 3 levels (3 neck sides), true-negative in 127 levels (23 neck sides), and false-positive in 6 levels (4 neck sides).
The 3 false-negative findings occurred in metastases smaller than 3 mm or because of inability to distinguish between primary tumor and adjacent metastasis. TP and false-positive nodes exhibited similar standardized uptakes (4.8 ± 1.1 vs. 4.2 ± 1.0; P = not significant). Sensitivity and specificity were 67% and 85% on the basis of neck sides and 67% and 95% on the basis of number of nodal levels, respectively.
If a decision regarding the need for neck dissection had been based solely on PET/CT, 3 false-negative necks would have been undertreated, and 4 false-positive necks would have been overtreated.

Conclusion:
18F-FDG PET/CT can identify lymph node metastases in a segment of patients with oral cancer and N0 neck. A negative test can exclude metastatic deposits with high specificity. Despite reasonably high overall accuracy, however, the clinical application of PET/CT in the N0 neck may be limited by the combination of limited sensitivity for small metastatic deposits and a relatively high number of false-positive findings. The surgical management of the N0 neck should therefore not be based on PET/CT findings alone.

Authors:
Heiko Schöder1, Diane L. Carlson2, Dennis H. Kraus3, Hilda E. Stambuk1, Mithat Gönen4, Yusuf E. Erdi5, Henry W.D. Yeung1, Andrew G. Huvos2, Jatin P. Shah3, Steven M. Larson1 and Richard J. Wong3

Authors’ affiliation:
1 Department of Radiology, Memorial Sloan-Kettering Cancer Center, New York, New York;
2 Department of Pathology, Memorial Sloan-Kettering Cancer Center, New York, New York;
3 Head and Neck Service, Department of Surgery, Memorial Sloan-Kettering Cancer Center, New York, New York;
4 Department of Biostatistics and Epidemiology, Memorial Sloan-Kettering Cancer Center, New York, New York; and
5 Department of Physics, Memorial Sloan-Kettering Cancer Center, New York, New York