2-[18F]Fluoro-2-Deoxyglucose Positron Emission Tomography for the Detection of Disease in Patients with Prostate-Specific Antigen Relapse after Radical Prostatectomy

Abstract

Experimental Design: Retrospective cohort study in 91patients with prostate-specific antigen (PSA) relapse following prostatectomy, imaged with 2-[18 F]fluoro-2-deoxyglucose positron emission tomography (FDG-PET) in a tertiary care cancer center between February 1997 and March 2003. Comparison was made with magnetic resonance imaging (n = 64), bone scan (n = 56), and computed tomography (n = 37). The standard of reference included biopsy or clinical and imaging follow-up. We calculated sensitivity and specificity of PET and correlated PET findings with PSA values, other clinical parameters, and conventional imaging, when available. Results: PET was true positive in 28 of 91 (31%) patients, showing isolated disease in the prostate bed (n = 3) or metastatic disease with (n = 2) or without (n = 23) simultaneous disease in the prostate bed. In detail, PET identified lesions in the prostate bed (n = 5, all true positives), bones (n = 22; 20 true positives, 2 false positives), lymph nodes (n = 7; 6 true positives, 1likely false positive), and one liver metastasis. Mean PSA was higher in PET-positive than in PETnegative patients (9.5 F 2.2 versus 2.1 F 3.3 ng/mL). PSA of 2.4 ng/mL and PSA velocity of 1.3 ng/mL/y provided the best tradeoff between sensitivity (80%; 71%) and specificity (73%; 77%) of PET in a receiver operating curve analysis. Combination with other clinical parameters in a multivariate analysis did not improve disease prediction. There were only two patients in whom other imaging studies showed isolated local recurrence or metastatic disease. Conclusions: FDG-PETdetected local or systemic disease in 31% of patients with PSA relapse referred for this test. There is a link to tumor burden and tumor biology in that the probability for disease detection increased with PSA levels.

PSMA Ligands for PET Imaging of Prostate Cancer

“…18 F-FDG is the most widely used radiotracer in oncologic PET/CT imaging; however, only a minority of PC (i.e., only aggressive, poorly differentiated, or undifferentiated PC) shows a high glycolytic rate, limiting the use of 18 F-FDG PET (7,8). In Europe, radiolabeled choline derivatives ( 18 F-fluorocholine or 11 C-choline) were among the most commonly used PET tracers for PC imaging.…”

Is there a role for positron emission tomography imaging in the early evaluation of prostate cancer relapse?

“…Schö der et al 23 showed that the proportion of FDG-PET-positive studies was significantly higher in patients with post-prostatectomy biochemical recurrence with higher PSA values. Although low PSA did not necessarily preclude PET positivity, 18 F-FDG-PET was most useful with PSA 42.4 ng ml À1 or a PSA velocity 41.3 ng per ml per year.…”

“…Thus, rather than simply replacing a tracer with another, a multitracer approach may be needed to fully exploit the potential of PET imaging in the setting of biochemical failure. 23,56 …”

“…36 Using this method, Turlakow et al 36 reported a high correlation between positive 18 F-FDG-PET findings and biopsyproven presence of disease in patients with primary or recurrent disease. In a recent analysis, however, Schö der et al 23 were able to detect disease in the prostate bed in only 5 of 21 patients. Overall, 18 F-FDG-PET was shown to be true positive in 31% of cases only (local and/or distant failure).…”

“…22,23 At the local level, conventional imaging methods may fail to discriminate between recurrent tumour and fibrosis after surgery and/or radiation therapy. 24 Metabolic imaging by positron emission tomography (PET) has been proposed as a possible solution to overcome the limitations of traditional anatomic imaging.…”