title: The role of 18F-fluorodeoxyglucose positron emission tomography in gestational trophoblastic tumours: a pilot study.
abstract: OBJECTIVE
  We conducted a pilot trial to evaluate the value of 18F-fluorodeoxyglucose (18F-FDG) positron emission tomography (PET) in gestational trophoblastic tumours (GTTs).
  
  
  METHODS
  Patients with placental site trophoblastic tumour (PSTT), high-risk GTT (World Health Organisation score > or =8, disease onset at postpartum or greater than 6 months after antecedent pregnancy), metastatic GTT, recurrent/resistant GTT after chemotherapy, or post-molar GTT with unexplained abnormal beta-hCG regression and patients undergoing re-evaluation after salvage treatment were enrolled. PET was undertaken within 1 week after computed tomography (CT). Clinical impacts of additional PET were determined on a scan basis.
  
  
  RESULTS
  A total of 14 patients were recruited. Sixteen PET scans were performed, with one patient having three serial studies. Benefits of additional PET were seen in 7 of 16 (43.8%) scans; these benefits included disclosure of chemotherapy-resistant lesions (n = 2), exclusion of false-positive CT lesions (n = 1), detection of an additional lesion not found by conventional imaging (n = 1) in high-risk GTT at the start of primary chemotherapy, and confirmation of complete response to treatment for PSTT or to salvage therapy for recurrent/resistant GTT (n = 3). On the other hand, in two instances there were false-negative PET findings, six scans yielded no benefit, and one showed an indeterminate lesion.
  
  
  CONCLUSIONS
  Our preliminary results suggest that 18F-FDG PET is potentially useful in selected patients with GTT by providing precise mapping of metastases and tumour extent upfront, by monitoring treatment response and by localising viable tumours after chemotherapy. A larger study is necessary to further define the role of 18F-FDG PET in GTT.
authors.affiliation: Division of Gynecologic Oncology, Department of Obstetrics and Gynecology, Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Taoyuan, Taiwan.
authors.forename: Ting Chang
authors.initials: TC
authors.lastname: Chang
authors.forename: Tzu Chen
authors.initials: TC
authors.lastname: Yen
authors.forename: Yiu Tai
authors.initials: YT
authors.lastname: Li
authors.forename: Yen Ching
authors.initials: YC
authors.lastname: Wu
authors.forename: Yu Cheng
authors.initials: YC
authors.lastname: Chang
authors.forename: Koon Kwan
authors.initials: KK
authors.lastname: Ng
authors.forename: Shih Ming
authors.initials: SM
authors.lastname: Jung
authors.forename: Tzu I
authors.initials: TI
authors.lastname: Wu
authors.forename: Chyong Huey
authors.initials: CH
authors.lastname: Lai
mesh_terms: D000328:Adult; D000970:Antineoplastic Agents / Q000494:pharmacology; D018997:Chorionic Gonadotropin, beta Subunit, Human / Q000097:blood; D005260:Female; D019788:Fluorodeoxyglucose F18; D031901:Gestational Trophoblastic Disease / Q000175:diagnosis* / Q000473:pathology; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008875:Middle Aged; D009362:Neoplasm Metastasis; D010865:Pilot Projects; D049268:Positron-Emission Tomography / Q000379:methods*; D011247:Pregnancy; D014057:Tomography, X-Ray Computed
chemical_list: D000970:Antineoplastic Agents; D018997:Chorionic Gonadotropin, beta Subunit, Human; D019788:Fluorodeoxyglucose F18