Early prediction of treatment response to high-dose salvage chemotherapy in patients with relapsed germ cell cancer using [18F]FDG PET

Abstract

To assess the ability of [ 18 F]fluorodeoxyglucose positron emission tomography for the early prediction of response in patients with relapsed metastatic germ cell tumours undergoing salvage high-dose chemotherapy. The role of positron emission tomography was compared with established means of tumour response assessment such as CT scans/MRI and serum tumour marker changes. In addition, positron emission tomography was compared with a current prognostic score which differentiates three prognostic groups with failure-free survival rates ranging from 5 -50%. [ 18 F]fluorodeoxyglucose uptake of metastases from germ cell tumours as well as CT scans and serum tumour marker were acquired after 2 -3 cycles of induction chemotherapy but before the start of high-dose chemotherapy and CT scans/serum tumour marker were compared with the baseline examinations in 23 patients with relapsed germ cell tumours. To evaluate the validity of early response prediction by positron emission tomography, radiological monitoring and serum tumour marker decline, histopathologic response after resection of residual masses and/or the clinical course over 6 months after the end of treatment (relapse vs freedom of progression) were used. Overall, 10 patients (43%) achieved a marker-negative partial remission, three (13%) a markerpositive partial remission, five (22%) a disease stabilization and five (22%) progressed during treatment. Nine patients (39%) remained progression-free over 6 months following treatment, whereas 14 (61%) progressed. The outcome of high-dose chemotherapy was correctly predicted by positron emission tomography/CT scan/serum tumour marker in 91/59/48%. Eight patients with a favourably predicted outcome by CT scans plus serum tumour marker but a positive positron emission tomography prior to high-dose chemotherapy, failed treatment. This results in the following sensitivities/specificities for the prediction of failure of high-dose chemotherapy: positron emission tomography 100/78%; radiological monitoring 43/78%; serum tumour marker 15/100%. The positive and negative predictive values of positron emission tomography were 88 and 100%, respectively. As compared with the prognostic score, positron emission tomography was correctly positive in all patients of the three risk groups who failed treatment. In addition, a negative positron emission tomography correctly predicted a favourable outcome in the good and intermediate group. [ 18 F]fluorodeoxyglucose positron emission tomography imaging can be used to assess response to chemotherapy in patients with relapsed germ cell tumours early in the course of treatment and may help to identify patients most likely to achieve a favourable response to subsequent high-dose chemotherapy. In patients with response to induction chemotherapy according to CT scans or serum tumour marker evaluation, positron emission tomography seems to add information to detect patients with an overall unfavourable outcome. It may also be a valuable addition to the prognostic model particularly in the goo...

FDG-PET in the management of germ cell tumor

“…FDG-PET performed early in the course of salvage treatment has provided independent prognostic information [23]. In particular, FDG-PET could be useful when mismatch between tumor marker and CT changes occurs and salvage surgery could be considered as an option [23,24]. However, larger trials are needed before drawing any firm conclusion.…”

“…In a recent study, the role of FDG-PET has been compared with established means of tumor response assessment such as CT and serum tumor marker changes in 23 patients with relapsed GCT treated with salvage chemotherapy [23]. FDG-PET performed early in the course of salvage treatment has provided independent prognostic information [23]. In particular, FDG-PET could be useful when mismatch between tumor marker and CT changes occurs and salvage surgery could be considered as an option [23,24].…”

“…In patients with relapsed/refractory GCT, FDG-PET might provide additional information to anatomic imaging techniques and tumor marker evaluation such as assessing subclinical response. In a recent study, the role of FDG-PET has been compared with established means of tumor response assessment such as CT and serum tumor marker changes in 23 patients with relapsed GCT treated with salvage chemotherapy [23]. FDG-PET performed early in the course of salvage treatment has provided independent prognostic information [23].…”

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

“…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.…”

PET/CT with 18F-FLT: Does It Improve the Therapeutic Management of Metastatic Germ Cell Tumors?

“…However, the role of 18 F-FDG PET in staging nonseminomatous residues is limited because 18 F-FDG PET cannot differentiate mature teratoma from necrosis and fibrosis (6,7,(9)(10)(11)(12). In predicting early therapy response, 18 F-FDG PET may have a role in poorprognosis GCT patients, as has been addressed in a pilot study with 19 patients (13,14).…”