Fluorodeoxyglucose positron emission tomography in the initial staging of germ cell tumours

Abstract

Testicular cancer is a rare tumour with the potential for cure at diagnosis. It is important, however, to identify those patients with metastases at presentation so as to ensure that the optimum treatment strategy is employed. Many criteria have been used to try to place patients into high- or low-risk groups, with variable success. Fluorine-18 fluorodeoxyglucose positron emission tomography (FDG-PET) has the potential to identify active disease and thereby influence further management. Here we report on a retrospective study of the use of FDG-PET in the detection of metastatic testicular carcinoma at diagnosis. Thirty-one patients [13 with seminoma and 18 with non-seminomatous germ cell tumours (13 teratomas, 5 mixed)] were staged by FDG-PET scanning. The imaging was performed using a Siemens ECAT 951 scanner. All results were assessed on the basis of histology or clinical follow-up. FDG-PET scan identified metastatic disease in ten and was negative in 16; there were no false-positives and five false-negatives. There were six patients in whom FDG-PET was negative and computed tomography was regarded as suspicious but follow-up was inconclusive. The positive predictive value was 100%. The negative predictive value was 76% or 91%, depending on whether the aforementioned six cases were regarded as true-negatives or false-negatives. It may be concluded that FDG-PET is capable of detecting metastatic disease at diagnosis that is not identified by other imaging techniques. These preliminary results are sufficient to suggest that a large prospective study should be performed to evaluate the role of FDG-PET in primary staging of disease.

Whole-body FDG-PET in patients with stage I non-seminomatous germ cell tumours

“…A recent retrospective study from the UK evaluated FDG-PET in the staging of germ cell tumours, and as in our study, there were no false positive findings. The negative predictive value and accuracy were higher in nonseminomas (18 patients) than in seminomas (13 patients) [29]. A prospective German study examined 37 patients with bulky seminoma and postchemotherapy masses and found that PET was able to identify viable tumour, especially in masses >3 cm [30].…”

“…After reconstruction of FDG concentrations throughout the object, areas of focal increased uptake can be visualised in axial, coronal and sagittal planes [23]. A number of studies of FDG-PET in patients with metastatic germ cell tumours have shown that this method may identify metastatic disease and residual disease after treatment [24,25,26,27,28,29,30,31,32,33,34,35,36], and it has been indicated that PET might play a role in locating metastatic disease [32,34].…”

FDG-PET in the management of germ cell tumor

“…Response to therapy is probably the best suited target for DNA-synthesis imaging with thymidine analogues labelled with 11 C or 18 F [25]. In the next future, the diffusion of this tracer will probably improve the impact of PET molecular imaging on pharmacological treatment planning of tumors.…”

Current management of stage I testicular non-seminomatous germ cell tumours

“…The clinical staging error remains an issue of concern although the false-negative staging error may be minimized by the evaluation of CT scans by doctors with expertise in specialized centers [29]. Positron emission tomography (PET) may improve the imaging results, but this approach is more important for clinical stage II disease [39,40]. Recently, Huddart et al [41] conducted a trial in high-risk patients in order to examine whether a PET scan could identify patients without occult metastatic disease for whom surveillance is an attractive option.…”