Value of whole body 18FDG-PET to identify the active site of gestational trophoblastic neoplasia.
OBJECTIVE
To evaluate the usefulness of positron emission tomography with 18-fluorodeoxyglucose (18FDG-PET) in locating residual or relapsed gestational trophoblastic neoplasia (GTN).


METHODS
The Charing Cross GTN database was screened, and 11 patients who had undergone 18FDG-PET were identified. A retrospective analysis was conducted to determine the value of this investigation as compared with other imaging modalities in clinical care.


RESULTS
All patients had elevated beta-human chorionic gonadotropin (beta-hCG) at the time of the investigation; none were false positive. In 7 patients the 18FDG-PET scans correctly confirmed the presence (4 of 7 cases) or absence (3 of 7 cases) of disease sites defined by other imaging investigations. In 2 patients positive PET-guided appropriate surgical resection of lung lesions that appeared of equivocal significance on computed tomography (CT) resulted in -hCG normalization. One patient had a pulmonary metastasis on CT not considered positive on 18FDG-PET (false negative). One patient with enlarged mediastinal lymph nodes on CT that were 18FDG-PET positive also had a vascular uterus on magnetic resonance imaging/Dopper ultrasound that was negative on PET (false negative). Hysterectomy led to hCG normalization and cure. The mediastinal lymph nodes were positive on CT and PET due to sarcoidosis (false positive). Patients with serum hCG levels <10 IU/L could have positive PET scans; that can contribute to patient care.


CONCLUSIONS
18FDG-PET can aid in identifying residual disease sites in women relapsing from previously treated GTN. However, careful evaluation in combination with other imaging modalities is required to reduce the risk of false positive and negative results.
Dhillon
Tony
T
Department of Medical Oncology, Charing Cross Hospital Campus of Imperial College, Fulham Palace Road, London W6 8RF, UK.
Palmieri
Carlo
C
Sebire
Neil J
NJ
Lindsay
Ian
I
Newlands
Edward S
ES
Schmid
Peter
P
Savage
Philip M
PM
Frank
John
J
Seckl
Michael J
MJ
D000328:Adult; D006063:Chorionic Gonadotropin / Q000097:blood; D005260:Female; D019788:Fluorodeoxyglucose F18; D031901:Gestational Trophoblastic Disease / Q000000981:diagnostic imaging* / Q000628:therapy; D006801:Humans; D049268:Positron-Emission Tomography; D011247:Pregnancy; D019275:Radiopharmaceuticals; D012189:Retrospective Studies
D006063:Chorionic Gonadotropin; D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18