Postoperative FDG-PET/CT staging in GIST: is there a benefit following R0 resection?
OBJECTIVE
Resection of the primary tumor with intraoperative staging is the standard procedure in patients with gastrointestinal stromal tumors (GIST). FDG-PET/CT has shown high accuracy when assessing treatment response in GIST patients. This study was designed to assess the accuracy of postoperative FDG-PET/CT to stage for occult tumor seeding in patients with R0 resection and without intraoperative detection of metastases.


METHODS
48 consecutive patients (mean age: 59 y) with histologically proven GIST underwent whole-body FDG-PET/CT after R0-resection without intraoperative detection of metastases. Fused data sets were assessed for metastases by a nuclear medicine physician and a radiologist. Histology of potential lesions and a clinical/radiological follow-up with a mean of 614±415 d served as standards of reference.


RESULTS
FDG-PET/CT detected occult peritoneal metastases in 2 patients (4%). In 6 patients (13%) who later developed metastases postoperative FDG-PET/CT was falsely negative. False-positive findings were detected in 5 cases (10%) caused by increased FDG-uptake due to tissue regeneration postoperatively. In 3 patients (6%) other, formerly unknown malignancies were detected. The sensitivity and specificity of FDG-PET/CT for the detection of intraoperatively occult GIST metastases were 25% and 88%, respectively.


CONCLUSIONS
FDG-PET/CT performed immediately after R0-resection of GIST without intraoperative detection of metastases does not seem to be a sufficient tool to detect clinically occult metastases.
Department of Diagnostic and Interventional Radiology and Neuroradiology, University Hospital Essen, University at Duisburg-Essen, Hufelandstrasse 55, 45127 Essen, Germany. steffen.hahn@uk-essen.de
Steffen
S
Hahn
Sebastian
S
Bauer
Till Alexander
TA
Heusner
Peter
P
Ebeling
Monia Estella
ME
Hamami
Alexander
A
Stahl
Michael
M
Forsting
Andreas
A
Bockisch
Gerald
G
Antoch
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D019788:Fluorodeoxyglucose F18; D005770:Gastrointestinal Neoplasms / Q000473:pathology* / Q000601:surgery*; D046152:Gastrointestinal Stromal Tumors / Q000473:pathology* / Q000601:surgery*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D049268:Positron-Emission Tomography / Q000379:methods*; D011182:Postoperative Care / Q000379:methods; D019275:Radiopharmaceuticals; D013382:Subtraction Technique; D014057:Tomography, X-Ray Computed / Q000379:methods*; D016896:Treatment Outcome
D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18