The role of positron emission tomography in the evaluation of residual masses after chemotherapy for advanced stage seminoma.
OBJECTIVE
Treatment in patients with seminoma who have residual or recurrent masses following chemotherapy is still a matter of debate. Surgical resection is currently the most common recommendation for masses greater than 3 cm, resulting in overtreatment in up to 70% of those affected. We analyzed the accuracy of preoperative positron emission tomography for predicting viable tumor residuals in patients with seminoma.


METHODS
In a prospective, multicenter trial computerized tomography and FDG (2-(F-18)-fluoro-2-deoxy-D-glucose) positron emission tomography were performed before surgical resection for residual or recurrent masses in 20 patients who had undergone chemotherapy for stage IIb, IIc or III seminoma. Histopathological findings were directly correlated with positron emission tomography results.


RESULTS
Of the patients 18 presented with residual masses and 2 had recurrent masses following chemotherapy. Histopathological assessment revealed viable tumor in 3 patients and benign lesions in 17. All patients with viable tumor were identified correctly by positron emission tomography. No false-negative results were observed but 9 patients had false-positive positron emission tomography results. This resulted in a negative predictive value of 1 (95% CI 0.63-1) and a positive predictive value of 0.25 (95% CI 0.05-0.57) for FDG-positron emission tomography in our patient cohort.


CONCLUSIONS
Our data indicate that FDG-positron emission tomography is capable of excluding viable disease in residual masses, even those exceeding 3 cm. Therefore, it may be considered an additional tool to improve patient counseling. However, the decision to perform surgical resection of the residual mass should not be based exclusively on a positive positron emission tomography image since false-positive results appear to be common.
Hinz
Stefan
S
Department of Urology, Charité Campus Benjamin Franklin, Universitaetsmedizin Berlin, Berlin, Germany. Stefan.hinz@charite.de
Schrader
Mark
M
Kempkensteffen
Carsten
C
Bares
Roland
R
Brenner
Winfried
W
Krege
Susanne
S
Franzius
Christiane
C
Kliesch
Sabine
S
Heicappel
Ruediger
R
Miller
Kurt
K
de Wit
Maike
M
D000328:Adult; D006801:Humans; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000000981:diagnostic imaging* / Q000473:pathology / Q000628:therapy; D018365:Neoplasm, Residual / Q000000981:diagnostic imaging* / Q000473:pathology / Q000601:surgery; D049268:Positron-Emission Tomography; D011237:Predictive Value of Tests; D011446:Prospective Studies; D018239:Seminoma / Q000000981:diagnostic imaging* / Q000473:pathology / Q000628:therapy; D013736:Testicular Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology / Q000628:therapy; D014057:Tomography, X-Ray Computed