International Journal of Radiation Oncology*Biology*Physics
Clinical investigationHead and neckImpact of FDG-PET/CT Imaging on Nodal Staging for Head-And-Neck Squamous Cell Carcinoma
Introduction
Advances in sophisticated radiotherapy (RT) techniques, notably three-dimensional conformal RT (3D-CRT) and intensity-modulated RT (IMRT), render the precise delineation of the gross tumor volume (GTV) essential for RT planning. This is particularly important in head-and-neck squamous cell carcinoma (SCC) where normal and abnormal structures are in close proximity. In the interpretation of morphologic imaging modalities such as computed tomography (CT) and magnetic resonance imaging (MRI), the GTV boundary is often vague in the presence of inflammatory changes around the tumor or interference by metal artifacts, and their normal appearance on these images renders the detection of metastatic lymph nodes difficult. These factors contribute to a marked variability in GTV assessments even among experienced radiation oncologists, resulting in a possible geographic miss of the tumor or unnecessary irradiation of normal tissues (1).
Functional imaging with 18F-fluorodeoxyglucose (FDG)-positron emission tomography (PET), which provides information about glucose metabolism, may improve the consistency of GTV delineation (2, 3, 4). 18F-fluorodeoxyglucose PET and its quantitative parameter, the standardized uptake value (SUV), have been used to evaluate the staging, treatment response, and recurrence detection of a wide range of solid cancers, including head-and-neck SCC. The sensitivity and specificity of FDG-PET for the detection of nodal involvement reportedly were 61–96% and 80–99%, respectively; with CT/MRI they were 53–82% and 71–97% (4, 5, 6, 7). On the other hand, because of the limited anatomic resolution of FDG-PET, precise tumor localization requires careful correlation with structural images. Imaging with PET/CT provides the morphologic information of CT and the functional information of PET (8, 9, 10, 11, 12).
Although FDG-PET/CT imaging has been used in the evaluation of head-and-neck SCC, its role in initial staging has not been fully addressed (13, 14, 15). Some studies reported that RT planning was changed on the basis of information yielded on FDG-PET/CT fused images; however, they did not provide pathologic confirmation of the imaging findings (16, 17, 18). The purpose of this study was to evaluate the impact of FDG-PET/CT imaging on nodal staging for head-and-neck SCC.
Section snippets
Methods and Materials
Written prior informed consent to undergo FDG-PET/CT imaging and receive treatments was obtained from all patients. The institutional review board of our hospital approved this retrospective study; patient informed consent for inclusion in this study was waived. To protect patient privacy, we removed all identifiers from our records at the completion of our analyses.
Results
Dissection was performed at 35 neck sites; of the 23 patients, 11 underwent unilateral and 12 bilateral dissections; 28 positive and 529 negative lymph nodes were pathologically isolated from 112 nodal levels, of which 19 were positive and 93 negative. Pathologically, 1 patient had T1, 6 had T2, 9 had T3, and 7 had T4 tumors; nodal involvement was N0 in 8, N1 in 8, N2b in 6, and N2c in 1 patient.
In all 23 primary tumors, FDG-PET/CT fused images demonstrated FDG accumulation. Based on FDG-PET/CT
Discussion
18F-fluorodeoxyglucose PET, a functional imaging methodology that provides information about tissue glucose metabolism, has been used for the evaluation of head-and-neck SCC. In our study, FDG-PET/CT fused images demonstrated FDG accumulation in all of the 23 primary tumors we examined. Among three protocols for nodal staging, FDG-PET/CT imaging with SUV data (Method 3) yielded the most correct lymph node staging for each observer. Previous studies of nodal staging with FDG-PET alone reported
Acknowledgments
The authors thank Prof. Masanori Shinohara from the Department of Oral and Maxillofacial Surgery and Prof. Eiji Yumoto from the Department of Otolaryngology–Head and Neck Surgery at Kumamoto University Hospital for clinical data collection; and Mr. Shinya Yamamoto from Uozumi Clinic for technical assistance.
References (23)
- et al.
Inter-observer variability in the delineation of pharyngo-laryngeal tumor, parotid glands and cervical spinal cord: Comparison between CT-scan and MRI
Radiother Oncol
(2005) - et al.
FDG-PET in radiotherapy treatment planning: Pandora’s box?
Int J Radiat Oncol Biol Phys
(2004) - et al.
PET imaging in oncology
Semin Nucl Med
(2000) - et al.
FDG-PET/CT imaging for preradiotherapy staging of head-and-neck squamous cell carcinoma
Int J Radiat Oncol Biol Phys
(2005) - et al.
Image fusion between 18FDG-PET and MRI/CT for radiotherapy planning of oropharyngeal and nasopharyngeal carcinomas
Int J Radiat Oncol Biol Phys
(2002) - et al.
Imaging of cervical lymph nodes in head and neck cancer: The basics
Radiol Clin North Am
(2006) - et al.
Initial experience of FDG-PET/CT guided IMRT of head-and-neck carcinoma
Int J Radiat Oncol Biol Phys
(2006) - et al.
Tumor volume in pharyngolaryngeal squamous cell carcinoma: Comparison at CT, MR imaging, and FDG PET and validation with surgical specimen
Radiology
(2004) - et al.
Prospective comparison of 18F-FDG PET with conventional imaging modalities (CT, MRI, US) in lymph node staging of head and neck cancer
Eur J Nucl Med
(1998) - et al.
18F-FDG PET and CT/MRI in oral cavity squamous cell carcinoma: A prospective study of 124 patients with histologic correlation
J Nucl Med
(2005)
Evaluation of 18 F-fluorodeoxyglucose positron emission tomography and computed tomography with histopathologic correlation in the initial staging of head and neck cancer
Ann Surg
Cited by (131)
Head and neck imaging
2022, Clinical PET/MRIReliability of MRI-Derived Depth of Invasion of Oral Tongue Cancer
2019, Academic RadiologyCitation Excerpt :Radiological studies are widely used for the diagnostic and clinical staging of patients with oral cavity cancer (1–14).
Management of the Neck in Oral Squamous Cell Carcinoma: Background, Classification, and Current Philosophy
2019, Oral and Maxillofacial Surgery Clinics of North AmericaHead and neck carcinoma – Carcinoma of unknown origin – Salivary gland cancer
2019, Medecine Nucleaire
Conflict of interest: none.