Prospective Evaluation of 18F-NaF and 18F-FDG PET/CT in Detection of Occult Metastatic Disease in Biochemical Recurrence of Prostate Cancer

Abstract

Purpose This study aimed to perform a prospective evaluation of 18F-NaF and 18F-FDG PET/CT in the detection of occult metastatic disease in men with prostate cancer and biochemical relapse. Methods Thirty-seven men with prostate-specific antigen (PSA) relapse (median, 3.2 ng/mL; range, 0.5–40.2 ng/mL) after definitive therapy for localized prostate cancer [26 radical prostatectomy (RP), 11 external beam radiation therapy] and negative conventional imaging underwent 18F-FDG and 18F-NaF PET/CT on 2 separate days within the same week. Studies were interpreted by 2 experienced radiologists in consensus for abnormal uptake suspicious for metastatic disease. The reference standard was a combination of imaging and clinical follow-up. Rank of PSA values for positive and negative PET/CT was compared using analysis of variance adjusting for primary therapy. Association between PSA and scan positivity in patients with RP was evaluated using Wilcoxon rank sum test. Results Result of the 18F-FDG PET/CT scan was positive for nodal disease in 2 patients. True-positive detection rate for occult osseous metastases by 18F-NaF PET/CT was 16.2%. Median PSA levels for positive versus negative PET/CT scans were 4.4 and 2.9 ng/mL, respectively, with the difference marginally significant in prostatectomized men (P = 0.072). Percentages of patients with either 18F-NaF– or 18F-FDG–positive PET/CT in RP and external beam radiation therapy were 10% (n = 10) and undefined (n = 0) for a PSA of 2 ng/mL or less, 29% (n = 7) and 50% (n = 2) for PSA greater than 2 ng/mL but 4 ng/mL or less,60% (n = 5) and 40%(n = 5) for PSA greater than 4 ng/mL but 10 ng/mL or less, and 25% (n = 4) and 25% (n = 4) for PSA greater than 10 ng/mL, respectively. Conclusions In biochemical relapse of prostate cancer, 18F-NaF PET/CT is useful in the detection of occult osseous metastases, whereas the yield of 18F-FDG PET/CT is relatively limited. 18F-NaF PET/CT positivity tends to associate with increasing PSA level in prostatectomized men and may occur in lower PSA ranges than conventionally recognized.

Molecular Imaging of Prostate Cancer with PET

“…It has restricted utility for the detection of local recurrence in the treated prostate bed because of overlap of uptake between recurrent tumor and posttherapy tissue changes. Furthermore, high urine activity in the nearby bladder can obscure local tumor uptake (6). 18 F-FDG PET/CT may be most useful in the evaluation of the extent and treatment response of castrate-resistant metastatic disease (7).…”

18F-fluorodeoxyglucose PET/CT for detection of disease in patients with prostate-specific antigen relapse following radical treatment of a local-stage prostate cancer

“…Lytic bone metastases are extremely rare in PCa. 18 F-fluorodeoxyglucose ( 18 F-FDG) positron emission tomography (PET)/CT has low sensitivity in the detection of the sclerotic metastatic lesions of PCa. However, in the detection of lytic PCa metastasis, 18 F-FDG PET/CT is useful (11).…”

“…18 F-fluorodeoxyglucose ( 18 F-FDG) positron emission tomography (PET)/CT has low sensitivity in the detection of the sclerotic metastatic lesions of PCa. However, in the detection of lytic PCa metastasis, 18 F-FDG PET/CT is useful (11). 18 F-or 11 C-choline, 18 F-or 11 C-acetate, the synthetic L-leucine analog anti-1-amino-3-…”

“…However, in the detection of lytic PCa metastasis, 18 F-FDG PET/CT is useful (11). 18 F-or 11 C-choline, 18 F-or 11 C-acetate, the synthetic L-leucine analog anti-1-amino-3-…”

“…An accumulation of evidence currently strongly suggests that 18 F-FDG PET/CT may aid in the evaluation of imaging for men with metastatic PCa (14).…”