title: Efficacy of FDG-PET for defining gross tumor volume of head and neck cancer.
abstract: We analyzed the data for 53 patients with histologically proven primary squamous cell carcinoma of the head and neck treated with radiotherapy between February 2006 and August 2009. All patients underwent contrast-enhanced (CE)-CT and (18)F-fluorodeoxyglucose (FDG)-PET before radiation therapy planning (RTP) to define the gross tumor volume (GTV). The PET-based GTV (PET-GTV) for RTP was defined using both CE-CT images and FDG-PET images. The CE-CT tumor volume corresponding to a FDG-PET image was regarded as the PET-GTV. The CE-CT-based GTV (CT-GTV) for RTP was defined using CE-CT images alone. Additionally, CT-GTV delineation and PET-GTV delineation were performed by four radiation oncologists independently in 19 cases. All four oncologists did both methods. Of these, PET-GTV delineation was successfully performed in all 19 cases, but CT-GTV delineation was not performed in 4 cases. In the other 15 cases, the mean CT-GTV was larger than the PET-GTV in 10 cases, and the standard deviation of the CT-GTV was larger than that of the PET-GTV in 10 cases. Sensitivity of PET-GTV for identifying the primary tumor was 96%, but that of CT-GTV was 81% (P < 0.01). In patients with oropharyngeal cancer and tongue cancer, the sensitivity of CT-GTV was 63% and 71%, respectively. When both the primary lesions and the lymph nodes were evaluated for RTP, PET-GTV differed from CT-GTV in 19 cases (36%). These results suggested that FDG-PET is effective for defining GTV in RTP for squamous cell carcinoma of the head and neck, and PET-GTV evaluated by both CE-CT and FDG-PET images is preferable to CT-GTV by CE-CT alone.
authors.affiliation: Department of Radiation Oncology, Nara Medical University, 840 Shijo-cho, Kashihara 634-8522, Japan.
authors.forename: Chikae
authors.initials: C
authors.lastname: Kajitani
authors.forename: Isao
authors.initials: I
authors.lastname: Asakawa
authors.forename: Fumiaki
authors.initials: F
authors.lastname: Uto
authors.forename: Emiko
authors.initials: E
authors.lastname: Katayama
authors.forename: Kazuya
authors.initials: K
authors.lastname: Inoue
authors.forename: Tetsuro
authors.initials: T
authors.lastname: Tamamoto
authors.forename: Norihisa
authors.initials: N
authors.lastname: Shirone
authors.forename: Hideyuki
authors.initials: H
authors.lastname: Okamoto
authors.forename: Tadaaki
authors.initials: T
authors.lastname: Kirita
authors.forename: Masatoshi
authors.initials: M
authors.lastname: Hasegawa
mesh_terms: D002294:Carcinoma, Squamous Cell / Q000000981:diagnostic imaging*; D003198:Computer Simulation; D003287:Contrast Media / Q000494:pharmacology; D005260:Female; D019788:Fluorodeoxyglucose F18; D006258:Head and Neck Neoplasms / Q000000981:diagnostic imaging*; D006801:Humans; D021621:Imaging, Three-Dimensional; D008297:Male; D015588:Observer Variation; D049268:Positron-Emission Tomography; D019275:Radiopharmaceuticals; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed
chemical_list: D003287:Contrast Media; D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18
keywords: FDG-PET; gross tumor volume; head and neck cancer; target delineation