18F-FDG PET in squamous cell carcinoma of the oral cavity and oropharynx: a study on inter- and intraobserver agreement.

PURPOSE: Good observer agreement is mandatory for an effective imaging technique. However, little is known about the observer agreement of fluorine-18 fluorodeoxyglucose ((18)F-FDG) positron emission tomography (PET) in head and neck squamous cell carcinoma. The aim of the present study was to evaluate the inter- and intraobserver agreement of interpretations of (18)F-FDG PET in head and neck SCC and to assess the influence of observer experience, tumor localizing, and tumor size on the agreement. PATIENTS AND METHODS: (18)F-FDG PET scans of 80 patients with oral and oropharyngeal SCC were reassessed twice by 2 experienced nuclear medicine physicians and 2 residents in nuclear medicine. The absolute agreement and Cohen's kappa were calculated by comparing the results of the 4 observers for the primary tumor, cervical metastases, and distant metastases/second primary tumor. To analyze the sensitivity and specificity, the results were compared with the findings from the histologic specimens or the follow-up data. RESULTS: The interobserver agreement of the nuclear medicine physicians revealed an absolute agreement and kappa of 0.91 and 0.58 for detecting the primary tumor, 0.94 and 0.83 for detecting cervical metastases, and 0.85 and 0.53 for detecting distant metastases/second primary tumors, respectively. The intraobserver agreement was greater overall than the interobserver agreement. Compared with the nuclear medicine physicians, the residents scored lower in interobserver agreement. The interobserver agreement decreased when localizing the malignancy more precisely. The agreement and sensitivity increased with tumor size. However, for small metastases, a high observer agreement was found owing to the nondetection of these malignancies. CONCLUSIONS: Good inter- and intraobserver agreement in SCC in the oral cavity or oropharynx with (18)F-FDG PET was found. Observer experience had limited influence on observer agreement. However, the agreement level decreased when a more precise anatomic tumor localization was required.

FDG PET in oral and oropharyngeal cancer. Value for confirmation of N0 neck and detection of occult metastases.

Treatment of the clinical N0 neck in squamous cell carcinoma (SCC) of oral cavity and oropharynx remains a dilemma. None of the current imaging modalities are able to detect the presence of micrometastases in the lymph nodes of clinical N0 necks reliably. The aim of this study was to determine the diagnostic properties of fluorine-18 fluorodeoxyglucose positron emission tomography (FDG PET) in patients clinically staged as N0. FDG PET results of 38 patients were compared to histologic specimens obtained with neck dissections or to follow-up. FDG PET performance was compared to computed tomography (CT), magnetic resonance imaging (MRI) or ultrasonography-guided fine needle aspiration cytology (USgFNAC). Sensitivity and specificity of FDG PET in detecting occult cervical metastases were 50% and 97% respectively. Although FDG PET performed better than conventional imaging modalities, sensitivity was lower than desired. As a consequence, clinical application of FDG PET in the patient staged as N0 is limited.

Detection of cervical metastases with (11)C-tyrosine PET in patients with squamous cell carcinoma of the oral cavity or oropharynx: A comparison with (18)F-FDG PET.

BACKGROUND: A disadvantage of 2-[(18)F]fluoro-2-deoxy-D-glucose ((18)F-FDG) positron emission tomography (PET) in head and neck cancer is that (18)F-FDG uptake is not specific to malignant tissue. To provide an alternative, radiolabeled amino acids such as L-1-[(11)C]-tyrosine ((11)C-TYR), were introduced because these are less avidly metabolized by inflammatory cells. METHODS: In this prospective study, we compared both (11)C-TYR PET and (18)F-FDG PET performance in detecting cervical metastases in 27 patients with a squamous cell carcinoma (SCC) of oral cavity or oropharynx. RESULTS: (11)C-TYR PET sensitivity, specificity, and accuracy for detecting nodal metastases were 33%, 100%, and 81%, respectively. With respect to (18)F-FDG PET, these figures were 67%, 97%, and 89%, respectively. Neck metastases not detected by (11)C-TYR PET were camouflaged by high tracer uptake by salivary glands. CONCLUSIONS: Because of bilateral accumulation of (11)C-TYR in salivary glands, (11)C-TYR PET is not suitable to replace (18)F-FDG PET in staging SCC of oral cavity and oropharynx.

FDG-PET and detection of distant metastases and simultaneous tumors in head and neck squamous cell carcinoma: a comparison with chest radiography and chest CT.

Detection of distant metastases and second primary tumors in patients with head and neck squamous cell carcinoma (HNSCC) is of importance because of the impact on treatment and prognosis. The aim of this study was to assess the value of whole-body fluorodeoxyglucose-positron emission tomography (FDG-PET) in detecting distant metastases and second primary tumors below clavicular level in HNSCC compared to chest CT and chest radiography (CXR). Patient records of 149 consecutive patients with a primary HNSCC in whom a whole-body FDG-PET for initial staging was performed were reviewed. FDG-PET showed a sensitivity and specificity for detecting distant disease of 92% and 93%, respectively. Chest CT (n=82) showed a sensitivity and a specificity of 74% and 61% respectively. CXR (n=106) showed a sensitivity and a specificity of 41% and 91%, respectively. FDG-PET was shown to be able to detect distant metastases and second primary tumors in HNSCC with a high sensitivity and specificity. The higher sensitivity of PET compared to chest CT is mainly due to the detection of extrapulmonary malignancy. Sensitivity of PET and CT were similar in detecting intrapulmonary malignancy, but PET specificity was significantly higher. FDG-PET helps to determine the nature of pulmonary lesions and might be considered as a first diagnostic modality for detecting distant disease in advanced HNSCC.

18F-FDG PET as a routine posttreatment surveillance tool in oral and oropharyngeal squamous cell carcinoma: a prospective study.

UNLABELLED: The purpose of this study was to evaluate the role and timing of serial (18)F-FDG PET scans as routine surveillance for detecting early locoregional recurrence, distant metastases, and second primary tumors in patients treated for advanced squamous cell carcinoma (SCC) in the oral cavity or oropharynx during the first year after completion of their curative treatment. METHODS: Forty-eight consecutive patients with SCC in the oral cavity or oropharynx were included after completing their initial therapy with curative intent. Prospective follow-up of the participants was 2-fold: regular follow-up (history and physical examination) and serial (18)F-FDG PET scans. Patients underwent standard follow-up and (18)F-FDG PET at 3, 6, 9, and 12 mo after initial treatment. Findings were validated by histopathology or 18 mo of clinical follow-up and imaging after initial treatment. RESULTS: Incidence of recurrences and second primary tumors was 27% and 10%, respectively. (18)F-FDG PET was significantly (P = 0.035) more often in agreement with the gold standard than was regular follow-up. (18)F-FDG PET showed a sensitivity, specificity, positive predictive value, and negative predictive value of 100%, 43%, 51%, and 100%, respectively. For regular follow-up, these values were 0%, 60%, 0%, and 50%, respectively. (18)F-FDG PET accounted for a change in diagnostics or treatment in 63% of the patients and regular follow-up in 25% of the patients. Sensitivity and specificity of (18)F-FDG PET were both irrespective of timing of (18)F-FDG PET. For the 3- and 6-mo posttherapy results combined, (18)F-FDG PET detected malignancy in 16 of the 18 patients. CONCLUSION: (18)F-FDG PET is a suitable routine posttreatment surveillance tool in oral and oropharyngeal SCC patients and detects malignancy before clinical suggestion by the regular follow-up arises. The best timing of a systematic (18)F-FDG PET scan is between 3 and 6 mo after treatment.