Posttreatment assessment of response using FDG-PET/CT for patients treated with definitive radiation therapy for head and neck cancers

Andrade, Regiane S.; Heron, Dwight E.; Degirmenci, Berna; Filho, Pedro A.A.; Branstetter, Barton F.; Seethala, Raja R.; Ferris, Robert L.; Avril, Norbert

doi:10.1016/j.ijrobp.2006.03.015

« Previous Next »International Journal of Radiation Oncology * Biology * Physics
Volume 65, Issue 5 , Pages 1315-1322, 1 August 2006

Posttreatment assessment of response using FDG-PET/CT for patients treated with definitive radiation therapy for head and neck cancers

Regiane S. Andrade, M.D.
- Department of Radiation Oncology, University of Pittsburgh Cancer Institute, University of Pittsburgh School of Medicine, Pittsburgh, PA, United States
Dwight E. Heron, M.D.
- Department of Radiation Oncology, University of Pittsburgh Cancer Institute, University of Pittsburgh School of Medicine, Pittsburgh, PA, United States
- Reprint requests to: Dwight E. Heron, M.D., Department of Radiation Oncology, University of Pittsburgh Cancer Institute, 5150 Centre Avenue, No. 545, Pittsburgh, PA 15232. Tel: (412) 623-6723
Berna Degirmenci, M.D.
- Division of Nuclear Medicine, Department of Radiology, University of Pittsburgh Cancer Institute, University of Pittsburgh School of Medicine, Pittsburgh, PA, United States
Pedro A.A. Filho, M.D.
- Department of Otolaryngology, University of Pittsburgh Cancer Institute, University of Pittsburgh School of Medicine, Pittsburgh, PA, United States
Barton F. Branstetter, M.D.
- Division of Neuroradiology, Department of Radiology, University of Pittsburgh Cancer Institute, University of Pittsburgh School of Medicine, Pittsburgh, PA, United States
- Department of Otolaryngology, University of Pittsburgh Cancer Institute, University of Pittsburgh School of Medicine, Pittsburgh, PA, United States
Raja R. Seethala, M.D.
- Department of Pathology, University of Pittsburgh Cancer Institute, University of Pittsburgh School of Medicine, Pittsburgh, PA, United States
Robert L. Ferris, M.D., Ph.D.
- Department of Otolaryngology, University of Pittsburgh Cancer Institute, University of Pittsburgh School of Medicine, Pittsburgh, PA, United States
Norbert Avril, M.D.
- Division of Nuclear Medicine, Department of Radiology, University of Pittsburgh Cancer Institute, University of Pittsburgh School of Medicine, Pittsburgh, PA, United States

Received 9 December 2005; received in revised form 9 March 2006; accepted 9 March 2006. published online 01 June 2006.

Purpose: The goal of this study was to evaluate coregistered [¹⁸F] fluorodeoxyglucose (FDG)–positron emission tomography (PET)/computed tomography (CT) for the detection of persistent disease after definitive radiation therapy in head and neck cancer.

Methods and Materials: Posttreatment FDG-PET/CT was performed in 28 patients on average 8 weeks (range, 4 to 15.7 weeks) after completing definitive radiation therapy. FDG-PET/CT was visually analyzed for the entire patient group and at two time points (4–8 and >8 weeks) after treatment. The contrast-enhanced CT portion of PET/CT was separately analyzed blinded to the results of coregistered FDG-PET/CT and classified as negative or positive for residual locoregional disease. Pathologic findings and clinical follow-up served as the reference standard.

Results: Follow-up data were available for all 28 patients (median, 17.6 months). Regarding the detection of residual disease, the overall sensitivity and specificity of FDG-PET/CT was 76.9% and 93.3%, respectively, compared with 92.3% and 46.7% for contrast-enhanced CT. The accuracy of FDG-PET/CT was 85.7%, compared with 67.9% for CT alone. All false-negative (n = 3) and false-positive (n = 1) FDG-PET/CT results occurred between 4 and 8 weeks after treatment. At 8 weeks or later after treatment, the specificity of CT was 28%, compared with 100% for FDG-PET/CT.

Conclusions: The metabolic-anatomic information from coregistered FDG-PET/CT provided the most accurate assessment for treatment response when performed later than 8 weeks after the conclusion of radiation therapy. FDG-PET/CT excelled by a higher specificity and overall diagnostic performance than CT imaging alone. These results support a potential clinical role of FDG-PET/CT in the early assessment of therapy response after definitive radiation therapy.

Keywords: FDG-PET/CT , IMRT , Head and neck cancer , Treatment response