Diagnostic Value of ¹⁸F-FDG Positron Emission Tomography for Detection and Treatment Control of Malignant Germ Cell Tumors

Abstract

Introduction: The role of positron emission tomography (PET) with 2-[¹⁸F]fluoro-2-deoxy-D-glucose ([¹⁸F]FDG) is currently under evaluation in urologic oncology. The aim of the present study was to investigate the use of [¹⁸F]FDG positron emission tomography ([¹⁸F]FDG-PET) in the detection and treatment control of malignant germ cell tumors compared to computed tomography (CT). Materials and Methods: Thirty-two PET studies and CT scans were carried out in 23 patients with histologically proven germ cell tumors (10 seminomas, 12 non-seminomatous germ cell tumors (NSGCT), 1 unclassified serologic recurrent disease) Lugano stage I–III. The scans were done either after initial diagnosis (n = 21) and/or within 3–45 days after chemotherapy was completed (n = 11). PET and CT were validated either by histology (n = 7) or clinical follow-up of 6–11 months after the last PET study has been performed (n = 16). Sensitivity, specificity, accuracy, positive and negative predictive values were determined for PET and CT. Differences between PET and CT for parameters of diagnostic value were evaluated by χ² test. Results: Although not statistically significant, the sensitivity, accuracy and negative predictive value were higher for PET than for CT with respect to the detection of metastatic infradiaphragmatic and supradiaphragmatic lesions after initial diagnosis. The specificity and positive predictive value of PET and CT were comparable. After chemotherapy, PET was found to be significantly superior in specificity and accuracy compared to CT with respect to infradiaphragmatic lesions (p < 0.05). False-positive PET findings in supradiaphragmatic lesions after chemotherapy occurred in the case of inflammatory processes and resulted in a loss of specificity and accuracy compared to CT (p < 0.05). Conclusions: These preliminary results demonstrate [¹⁸F]FDG-PET to be a useful diagnostic tool for the initial staging and treatment control in patients with germ cell tumors. Possible advantages compared to CT, however, are as yet not clearly defined. The possibility of false-positive PET findings due to reactive supradiaphragmatic inflammatory processes early after chemotherapy have to be considered.

Diagnostic Accuracy of 18F-FDG-PET in Patients with Testicular Cancer: a Meta-analysis

“…And another possible reason for false-positive is nonspecific inflammatory processes after chemotherapy Tsatalpas et al, 2002;Albers et al, 2004;Johns Putra et al, 2004). In this regard, it might be of principal importance that we should do the examination before chemotherapy or have an interval of at least 4 weeks after chemotherapy (De Santis et al, 2004;Becherer et al, 2005).…”

“…Ultimately, 21 studies were excluded for undesirable article types (n=21), not written in English (n=6), and insufficient data (n=4), letter (n=2), case report (n=1), and review (n=8). Thus, 16 studies were included in our final dataset for the meta-analysis (Cremerius et al, 1998;Albers et al, 1999;Cremerius et al, 1999;Hain et al, 2000;Bokemeyer et al, 2002;Spermon et al, 2002;Tsatalpas et al, 2002;Lassen et al, 2003;De Santis et al, 2004;Becherer et al, 2005;de Wit et al, 2008;Hinz et al, 2008;Oechsle et al, 2008;Akbulut et al, 2011;Bachner et al, 2012;Siekiera et al, 2012). The flowchart of study selection was shown in Figure 1.…”

“…The uptake values in both residual masses containing necrotic and benign differentiated teratoma are lower than that in active tumor (Stephens et al, 1996). Furthermore, FDG-PET has more advantages compared to CT and tumor makers, especially in patients with a negative CT scan, PET may be able to identify the metastatic lesion (Tsatalpas et al, 2002). Alecander Becherer et al have reported that FDG-PET is superior to CT in the prediction of viable tumor in seminoma residuals after chemotherapy, with a sensitivity/specificity of 80%/100%, while CT had only 70%/74% (Becherer et al, 2005).…”

Clinical applications of positron emission tomography-computed tomography in oncology

“…Many authors have evaluated the role of FDG-PET for initial staging and produced variable results. [133][134][135][136] Tsatalpas et al compare PET and CT in 32 patients with testicular cancer. [134] Though not statistically significant, FDG-PET was found superior to CT scan in detecting metastatic infradiaphragmatic and supradiaphragmatic lesions.…”

“…[133][134][135][136] Tsatalpas et al compare PET and CT in 32 patients with testicular cancer. [134] Though not statistically significant, FDG-PET was found superior to CT scan in detecting metastatic infradiaphragmatic and supradiaphragmatic lesions. In a recent study, Lassen et al studied the role of FDG-PET in Stage I nonseminomatous germ cell tumors, with normal findings on conventional imaging.…”