ABSTRACT
Background: The staging and treatment planning of nasopharyngeal carcinoma (NPC) face challenges due to limited sensitivity of conventional imaging. 18F-sodium fluoride (18F-NaF) positron emission tomography-computed tomography (PET/CT) offers potential advantages in detecting early bone involvement. This retrospective cohort study aimed to assess the potential advantage of 18F-NaF PET/CT for clinical staging and management planning in patients with NPC and to compare 18F-NaF PET/CT findings with those of conventional imaging modalities. Methods: We enrolled a cohort of patients with NPC who underwent 18F-NaF PET/CT at our PET/CT center between July 1, 2017, and June 30, 2021, and analyzed the findings of 18F-NaF PET/CT and conventional imaging modalities. Data from multidisciplinary team discussions on clinical staging and management planning both before and after 18F-NaF PET/CT were recorded. Additionally, any changes in clinical staging and management planning following 18F-NaF PET/CT were documented. Results: A total of 58 patients were included in this study. After 18F-NaF PET/CT imaging, clinical tumor-node-metastasis (TNM) staging was observed to have changed in seven cases (12.1%). Among these, four cases had changes in T stage and three cases in the M stage. Additionally, changes in clinical management plans were observed in eight patients (13.8%). Changes due the results of 18F-NaF PET/CT included three cases with major modification (two cases switched from curative treatment to palliative treatment, and one case switched from palliative treatment to curative treatment) and five cases with minor changes. The minor changes involved alteration to the radiotherapy target volume (three cases with an increased target volume and one case with a reduced target area). Furthermore, one case required an alteration to the radiotherapy strategy for local bone involvement. Conclusions: The use of 18F-NaF PET/CT in patients newly diagnosed with NPC may offer potential advantages for clinical staging and treatment planning, enabling physicians to select a more individualized treatment approach.
ABSTRACT
To assess the diagnostic value of 18F-NaF PET/CT in diagnosing bone metastases in patients with nasopharyngeal carcinoma (NPC) using visual and quantitative analyses. 164 patients with NPC who underwent 18F-NaF PET/CT between 2017 and 2021 were included. The sensitivity, specificity, and accuracy were calculated. All bone lesions were divided into metastatic bone lesion group and benign lesion group; the benign lesion group was further subdivided into benign lesion without osteophyte and fracture group (CT images showing no osteophyte, no fracture), and benign lesion with osteophyte and fracture group (CT images showing typical osteophytes and fractures), the differences in maximum standardized uptake value (SUVmax) were compared between every two groups, and the diagnostic cut-off values were derived from receiver operating characteristic curves (ROC). Quantitative data were expressed as mean ± SD, multiple continuous variables were compared using one-way analysis of variance (ANOVA), and multiple comparisons among more than two groups were made using the Bonferroni method. The sensitivity, specificity, and overall accuracy of 18F-NaF PET/CT for the diagnosis of bone metastases in NPC were 97.1%, 94.6%, and 95.1% based on the patient level and 99.5%, 91.5%, and 96.4% based on the lesion level, respectively. The SUVmax was significantly different between the metastatic bone lesion group and the benign lesion without osteophyte and fracture group (p < 0.05); the area under the curve was 0.865, the threshold was 12.5, the sensitivity was 0.912, and the specificity was 0.656. Visual analysis of 18F-NaF PET/CT has high sensitivity and specificity for diagnosing bone metastases in NPC. After excluding osteophytes and fracture lesions based on CT findings, using SUVmax ≥12.5 as the threshold can be an important reference for the differential diagnosis of bone metastases and benign bone lesions in patients with NPC.
ABSTRACT
Purpose: Our study aims to compare the diagnostic value of 18F-NaF positron emission tomography-computed tomography (PET/CT), 18F-NaF PET, and planar 99mTc-MDP bone scintigraphy for detection of bone metastases in patients with newly diagnosed nasopharyngeal carcinoma (NPC). Methods: Our study retrospectively analyzed 58 patients with pathologically proven NPC. They all underwent both 18F-NaF PET/CT and planar 99mTc-MDP bone scintigraphy within a 7-day interval. Bone metastases were confirmed by follow-up using PET/CT, contrast-enhanced computed tomography (CT), and magnetic resonance imaging (MRI). These three examinations were compared using per-patient-based analysis and per-lesion-based analysis. Results: 19 patients (32.7%) were classified as having bone metastatic disease in their final diagnosis. The patient-based diagnostic performances (sensitivity, specificity, and overall accuracy) were as follows: 18F-NaF PET/CT (100%, 92.3%, and 94.8%), 18F-NaF PET (100%, 53.8%, and 69.0%), and planar 99mTc-MDP bone scintigraphy (78.9%, 74.4%, and 75.9%). The overall accuracy of 18F-NaF PET/CT was significantly more favorable compared to 18F-NaF PET (p=0.002) and to planar 99mTc-MDP bone scintigraphy (p=0.044). The lesion-based diagnostic performances (sensitivity, specificity, and overall accuracy) were as follows: 18F-NaF PET/CT (98.5%, 93.9%, and 96.6%), 18F-NaF PET (98.5%, 57.1%, and 81.1%), and planar 99mTc-MDP bone scintigraphy (69.9%, 85.7%, and 76.4%). Conclusion: 18F-NaF PET/CT outperforms 18F-NaF PET or planar 99mTc-MDP bone scintigraphy in detecting bone metastases with newly diagnosed NPC on a patient-based and lesion-based analysis.
