Prospective comparison of [¹⁸F]fluorodeoxyglucose positron emission tomography with conventional assessment by computed tomography scans and serum tumor markers for the evaluation of residual masses in patients with nonseminomatous germ cell carcinoma

Abstract

BACKGROUNDTo assess the ability of [18F]fluorodeoxyglucose (F‐18 FDG) positron emission tomography (PET) to predict the viability of residual masses after chemotherapy in patients with metastatic nonseminomatous germ cell tumors (GCT), PET results were compared in a blinded analysis with computed tomography (CT) scans and serum tumor marker changes (TUM) as established methods of assessment.METHODSIndependent reviewers who were blinded to each other's results evaluated the PET results and corresponding CT scan and TUM results in 85 residual lesions from 45 patients. All patients were treated within prospective clinical trials and received primary/salvage, high‐dose chemotherapy with autologous blood stem cell support for primary poor prognosis disease or recurrent disease. PET results were assessed both visually and by quantifying glucose uptake (standardized uptake values). Results were validated either by histologic examination of a resected mass and/or biopsy (n = 28 lesions) or by a 6‐month clinical follow‐up after evaluation (n = 57 lesions).RESULTSF‐18 FDG PET showed increased tracer uptake in 32 of 85 residual lesions, with 29 true positive (TP) lesions and three false positive (FP) lesions. Fifty‐three lesions were classified by PET as negative (no viable GCT), 33 lesions were classified by PET as true negative (TN), and 20 lesions were classified by PET as false negative (FN). In the blinded reading of the corresponding CT scan and TUM results, 38 residual lesions were assessed correctly as containing viable carcinoma and/or teratoma. Forty‐six lesions were classified as nonsuspicious by CT scan/TUM (33 TN lesions and 14 falsely classified lesions). PET correctly predicted the presence of viable carcinoma in 5 of these 14 and the absence of viable carcinoma in 3 of these 14 lesions. Resulting sensitivities and specificities for the prediction of residual mass viability were as follows: PET, 59% sensitivity and 92% specificity; radiologic monitoring, 55% sensitivity and 86% specificity; and TUM, 42% sensitivity and 100% specificity. The positive and negative predictive values for PET were 91% and 62%, respectively. The diagnostic efficacy of PET did not improve when patients with teratomatous elements in the primary tumor were excluded from the analysis. In patients with multiple residual masses, a uniformly increased residual F‐18 FDG uptake in all lesions was a strong predictor for the presence of viable carcinoma.CONCLUSIONSF‐18 FDG PET imaging performed in conjunction with conventional staging methods offers additional information for the prediction of residual mass histology in patients with nonseminomatous GCT. A positive PET is highly predictive for the presence of viable carcinoma. Other useful indications for a PET examination include patients with multiple residual masses and patients with marker negative disease. Cancer 2002;94:2353–62. © 2002 American Cancer Society.DOI 10.1002/cncr.10494

FDG-PET in the management of germ cell tumor

“…FDG-PET results were compared in a blinded analysis with CT scans and serum tumor marker changes as established methods of assessment in 85 residual lesions from 45 patients with nonseminomatous disease enrolled in a prospective study [34]. PET assessment demonstrated positive and negative predictive values of 91% and 62%, respectively, in differentiating tumor from non tumor lesions.…”

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

“…Moreover, the value of PET imaging was investigated comparing it to an established prognostic model as well as to conventional means of response assessment such as CT scans/MRI and the changes of TUM levels. Studies in different tumour types have demonstrated the ability of PET to clinically document tumour response to chemotherapy as well as its diagnostic value in the staging of cancer (Huovinen et al, 1993;Findlay et al, 1996;Flamen et al, 1999;Kollmannsberger et al, 2002). Wahl et al (1993) were among the first who reported that PET may have a substantial role as an early non-invasive method for the assessment of the efficacy of treatment.…”

“…Standardized uptake values (SUV), a quantitative measure of tumour uptake of the tracer, adjusted for injected dose and body weight, were calculated, if an increased uptake was observed in the tumour area (Leskinen et al, 1991;Strauss and Conti, 1991). Patients with a SUV of 52 were considered positive (Kollmannsberger et al, 2002).…”

“…Since cancer cells are characterized by a higher glucolytic rate than normal tissue cells, PET exploits this difference by assessing the rate and quantity of F-18 FDG uptake by the tumour. Studies have investigated the role of PET for the evaluation of residual masses in patients with germ cell tumours (GCT) after chemotherapy demonstrating the additional value of PET imaging for the detection of viable carcinoma in residual masses of both patients with seminomatous and non-seminomatous germ cell cancer (Stephens et al, 1996;Cremerius et al, 1998;Ganjoo et al, 1999;De Santis et al, 2001;Kollmannsberger et al, 2002). However, no study has so far reported the ability of PET to predict response during standard-dose or HD-CTX in patients with germ cell cancer.…”

Successful Resection of a Mediastinal Nonseminomatous Germ Cell Tumor Who’s Response to Induction Chemotherapy was Evaluated by Fluorodeoxyglucose-Positron Emission Tomography

“…Recently, fluorodeoxyglucose-positron emission tomography (FDG-PET) has been widely used for evaluating the response of gonadal GCT to chemotherapy in the management of the tumor including gonadal GCT [5]. Here, we report a case of mediastinal nonseminomatous yolk sac tumor showing a decreasing FDG uptake postchemotherapy, with no viable tumor cells histopathologically upon resection of the surgical specimen.…”