Positron emission tomography and clinical predictors of survival in primary extragonadal germ cell tumors.
BACKGROUND
Primary extragonadal germ cell tumors (EGTs) are an uncommon malignancy -accounting for 2-4% of all germ cell neoplasms in adult males. Their prognosis is worse than that for testicular germ cell tumors because of their relative chemoresistance and frequent presentation with widely disseminated metastases. We have studied the role of fluorodeoxyglucose positron emission tomography (FDG-PET) for outcome prediction of patients with EGTs.


METHODS
We have retrospectively analysed 36 men with germ cell tumors originating in the mediastinum or the retroperitoneum. All patients were treated between 1994 and 2010. Negative result of testicular ultrasonographic examination and/or testicular biopsy was required for diagnosis of EGT. Platinum-based systemic therapy was used in all cases, and resectable residual tumor masses were removed surgically.


RESULTS
Overall survival at one and three years was 81% (95% confidence interval [CI]: 68-94%) and 55% (CI: 38-71%), respectively. None of the patients who had positive FDG-PET findings after first line chemotherapy survived at three years after diagnosis. In contrast, 69% and 20% of patients with positive tumor markers, and 90% and 67% of patients with negative tumor markers after first line chemotherapy survived at one and three years, respectively. Negative FDG-PET after completion of treatment was also a powerful predictor of long-term survival with 100% patients surviving three years and 89% surviving five years after diagnosis.


CONCLUSIONS
Negative FDG-PET after first-line chemotherapy or after the completion of systemic treatment and resection of residual tumor masses strongly predicts long-term event-free survival in patients with EGTs.
Department of Oncology, Thomayer University Hospital and 1st Faculty of Medicine, Charles University, Prague, Czech Republic. tomas.buchler@ftn.cz
T
T
Buchler
P
P
Dusek
A
A
Brisuda
K
K
Simonova
P
P
Fencl
J
J
Jarkovsky
M
M
Babjuk
J
J
Abrahamova
D000293:Adolescent; D000328:Adult; D000368:Aged; D019788:Fluorodeoxyglucose F18; D006801:Humans; D008297:Male; D008479:Mediastinal Neoplasms / Q000000981:diagnostic imaging* / Q000401:mortality / Q000628:therapy; D008875:Middle Aged; D009373:Neoplasms, Germ Cell and Embryonal / Q000000981:diagnostic imaging* / Q000401:mortality / Q000628:therapy; D049268:Positron-Emission Tomography; D011379:Prognosis; D019275:Radiopharmaceuticals; D012186:Retroperitoneal Neoplasms / Q000000981:diagnostic imaging* / Q000401:mortality / Q000628:therapy; D015996:Survival Rate; D055815:Young Adult
D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18