(18)F-FDG PET/CT and histology for diagnosing recurrent/remnant tumors in head and neck cancer patients treated with radiotherapy.

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(18)F-FDG PET/CT and histology for diagnosing recurrent/remnant tumors in head and neck cancer patients treated with radiotherapy.

Hell J Nucl Med. 2017 Jul 12;:

Authors: Han EJ, O JH, Yoo IR, Kim YS, Kim MS, Kang JH, Choi WH

Abstract
OBJECTIVE: The aim of this study was to assess the diagnostic performance of fluorine-18-fluoro-2-deoxyglucose ((18)F-FDG) positron emission tomography (PET)/computed tomography (CT) for locoregional recurrent/residual tumor in patients with head and neck cancer (HNC) who underwent previous radiotherapy (RT).
SUBJECTS AND METHODS: (18)F-FDG PET/CT images from patients with HNC who previously underwent RT were retrospectively reviewed. Only cases with histological confirmation within 4 weeks of PET/CT imaging were included. Standardized uptake values were obtained for lesions and PET/CT findings were compared with histological results.
RESULTS: Of 181 cases, 114 (63%) were histologically confirmed as malignant and 67 (37%) as benign. The sensitivity, specificity, and accuracy of PET/CT were 93%, 64%, and 82%, respectively. Inflammation was the most common cause of false positives and small tumor volume and low (18)F-FDG avidity were the causes of false negatives. PET/CT had 100% sensitivity and 56% specificity for detecting recurrent or residual disease within 12 weeks after RT and 93% sensitivity and 64% specificity, more than 12 weeks after RT. The frequency of false positives in PET/CT images within 12 weeks of RT was similar to the results obtained 12 weeks after RT (15% vs. 14%). False positives were more frequent in PET/CT cases after two-dimensional or three-dimensional conformal RT than in those after intensity-modulated RT, although not statistically significant (15% vs. 9%, p>0.05).
CONCLUSION: (18)F-FDG PET/CT might aid the diagnosis of locoregional residual/recurrent tumors in patients with HNC previously treated with RT. Inflammation was the main cause of false positives regardless of the interval between RT and PET/CT, even several years after RT. Therefore, histological verification of positive PET/CT findings should be conducted during follow-up of HNC patients treated with RT.

PMID: 28697190 [PubMed - as supplied by publisher]

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