Predictive impact of 2-18fluoro-2-deoxy-D-glucose positron emission tomography for residual postchemotherapy masses in patients with bulky seminoma.
OBJECTIVE
To establish the predictive potential of 2-18fluoro-2-deoxy-D-glucose positron emission tomography (FDG PET) for detecting viable tumor tissue in residual postchemotherapy masses of seminoma patients.


METHODS
In this prospective multicenter trial, results of FDG PET studies in seminoma patients with postchemotherapy masses > or = 1 cm were correlated with either the histology of the resected lesion or the clinical outcome on follow-up without resection. Negative PET scans of residual lesions that were devoid of viable tumor tissue on resection or disappeared, shrunk, or remained stable in size for at least 2 years were rated as true-negative (TN). Positive scans without histologic or clinical evidence of tumor tissue were classified as false-positive. In patients with histologically positive or progressive lesions, positive PET scans were defined as true-positive (TP) and negative scans, false-negative (FN).


RESULTS
Thirty-seven PET scans of 33 patients were assessable at a median follow-up time of 23 months (range, 2 to 46 months). Histologic data were available from nine patients who had undergone resection. Twenty-eight patients were followed-up clinically and radiologically. Twenty-eight scans were TN, eight were TP, and one was FN. All 14 residual lesions more than 3 cm and 22 (96%) of the 23 < or = 3 cm were correctly predicted by FDG PET. The specificity (100%; 95% confidence interval [CI], 87.7% to 100%), sensitivity (89%; 95% CI, 51.7% to 99.7%), positive predictive value (100%), and the negative predictive value (97%) of FDG PET were superior to data obtained by assessing residual tumor size (< or = or > 3 cm).


CONCLUSIONS
FDG PET is a clinically useful predictor of viable tumor in postchemotherapy residuals of pure seminoma, especially those greater than 3 cm.
De Santis
M
M
Department of Medical Oncology and Luwdig Boltzmann Institute for Applied Cancer Research, Kaiser Franz Josef Spital, Wien, Austria.
Bokemeyer
C
C
Becherer
A
A
Stoiber
F
F
Oechsle
K
K
Kletter
K
K
Dohmen
B M
BM
Dittrich
C
C
Pont
J
J
D000328:Adult; D019788:Fluorodeoxyglucose F18; D006801:Humans; D008297:Male; D008875:Middle Aged; D018365:Neoplasm, Residual / Q000000981:diagnostic imaging; D011237:Predictive Value of Tests; D011446:Prospective Studies; D019275:Radiopharmaceuticals; D018239:Seminoma / Q000000981:diagnostic imaging* / Q000188:drug therapy; D012680:Sensitivity and Specificity; D013736:Testicular Neoplasms / Q000000981:diagnostic imaging* / Q000188:drug therapy; D014055:Tomography, Emission-Computed
D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18