Current situation and cost-effectiveness of 18F-FDG PET/CT for the diagnosis of fever of unknown origin and inflammation of unknown origin: A single-center, large-sample study from China.

PURPOSE: 18F-FDG PET/CT has an important role in the evaluation of fever of unknown origin (FUO) and inflammation of unknown origin (IUO). Our study was to investigate the current status of the inclusion of 18F-FDG PET/CT within FUO/ IUO diagnostic work-up and evaluate the cost-effectiveness of it in China. METHODS: A total of 741 FUO/IUO patients admitted to our hospital from January 2012 to December 2019 were retrospectively reviewed. The clinical characteristic, medical expenses to reach diagnosis and the proportion of definite etiological diagnosis achieved upon hospital discharge were compared between patients examined by 18F-FDG PET/CT (18F-FDG PET/CT group) and patients not examined by 18F-FDG PET/CT (non-18F-FDG PET/CT group). RESULTS: The mean age, proportion of critically-ill patients, proportion of rheumatologic diseases, the number of examinations and hospitalisation days to reach diagnosis in the 18F-FDG PET/CT group were significantly higher than those in the non-18F-FDG PET/CT group. The mean medical costs of 18F-FDG PET/CT group were significantly higher than those of non-18F-FDG PET/CT group, whereas the proportion of definite etiological diagnosis achieved upon hospital discharge of 18F-FDG PET/CT group was significantly higher than that of non-18F-FDG PET/CT group. The mean hospitalisation days and mean medical costs before diagnosis were significantly lower in patients who undertook 18F-FDG PET/CT ≤ 7 days after hospital admission than those in patients who undertook 18F-FDG PET/CT > 7 days after hospital admission. CONCLUSIONS: 18F-FDG PET/CT is mostly used in critically-ill and hard-to-diagnose FUO/IUO patients currently in China, which may conceal its cost-effective advantage. While the early use of 18F-FDG PET/CT according to patient characteristics and etiological clues could help to reduce hospitalization stay, limit medical costs, thus producing its diagnostic effect to the great extent.

[Value of (18)F-FDG imaging and serum tumor markers in the diagnosis of recurrent endometrial carcinoma].

OBJECTIVE: Both (18)F-fluorodeoxyglucose (FDG) imaging and serum tumor marker measurements can be used in the post-therapy surveillance of recurrent endometrial carcinoma, but the relationship between those two methods has not been demonstrated yet. The purpose of this study was to compare the diagnostic efficiency of (18)F-FDG imaging and serum tumor marker measurements in the diagnosis of recurrent endometrial carcinoma, as well as to analyze the correlation between those two methods. METHODS: Thirty-five patients with histopathologically confirmed endometrial carcinoma and suspected to have recurrent disease during post-therapy surveillance were included in this study. (18)F-FDG images from the thorax to the pelvis were obtained in all patients by using GE-Millennium VG Hawkeye system, and the abnormal FDG uptake was judged as tumor recurrence. Serum CA-125 and CP-2 were also measured for each patient by enzyme-linked immunoassay, and a cutoff value of 35 U/ml was taken as the criteria for predicting tumor recurrence. Based on the final clinical diagnosis, the efficiency of tumor markers (CA-125, CP-2) and (18)F-FDG imaging in the diagnosis of recurrent tumor was evaluated. RESULTS: According to the histopathological diagnosis or follow-up examinations, tumor recurrence was confirmed in 13 of the 35 patients. Elevated serum level of CA-125 was found in 7 patients, serum CP-2 was increased in 9, and (18)F-FDG imaging was positive in 15. The diagnostic sensitivity, specificity and accuracy were 53.8%, 100% and 82.9% for the serum CA-125; 38.5%, 81.0% and 65.7% for the serum CP-2, and 100%, 90.9% and 94.3% for the (18)F-FDG imaging, respectively. The diagnostic coincidence rate between the (18)F-FDG imaging and serum CA-125 was 77.1% (Kappa = 0.50, P = 0.001), but no significant correlation was found between the (18)F-FDG imaging and serum CP-2. In the patients with true positive (18)F-FDG imaging, a positive correlation between the tumor volume and the serum CA-125 value was found (r = 0.89, P < 0.001), but no correlation was found between the tumor uptake and the serum CA-125 values. CONCLUSION: For the post-therapy surveillance of patients with endometrial carcinoma, serum CA-125 is a high specific tumor marker for diagnosing recurrent disease and better than CP-2, but (18)F-FDG imaging is better than CA-125, and there is a positive correlation between tumor volume and serum CA-125 value.