Pitfalls of positive findings in staging esophageal cancer with F-18-fluorodeoxyglucose positron emission tomography.
BACKGROUND
18-F-fluorodeoxyglucose positron emission tomography (FDG-PET) is valuable in staging of esophageal cancer. However, FDG-PET may falsely upstage patients leading to incorrect exclusion from surgical treatment. This study was performed to determine the false-positive rate and possible causes.


METHODS
The rate of false-positive lesions on FDG-PET was documented in 86 out of a group of 98 patients. Lesions were defined as false positive when pathological examination was negative or as absence of tumor activity within 6 months of follow-up. To evaluate the influence of a learning curve on the false-positive rate, the PET scans were revised recently.


RESULTS
False-positive lesions were found in 13 patients (13 of 86; 15%). FDG-PET incorrectly revealed only locoregional node metastases in 5 patients in whom surgery with curative intent was performed. Ten lesions in the other 8 patients were classified as distant organ or as nonregional node metastases (M1a/1b). Finally, 5 patients upstaged to M1a/1b underwent a curative resection. The number of false-positive lesions decreased from 16 to 5 (6%) after revision.


CONCLUSIONS
Proper interpretation of FDG-PET in staging esophageal cancer is impeded by false-positive results. Even after completion of the learning curve, positive FDG-PET findings still have to be confirmed by additional investigations.
Department of Surgical Oncology, Groningen University Hospital, The Netherlands.
Henderik L
HL
van Westreenen
Pierre A M
PA
Heeren
Pieter L
PL
Jager
Hendrik M
HM
van Dullemen
Henk
H
Groen
John Th M
JT
Plukker
D000230:Adenocarcinoma / Q000000981:diagnostic imaging* / Q000473:pathology*; D000328:Adult; D000368:Aged; D002294:Carcinoma, Squamous Cell / Q000000981:diagnostic imaging* / Q000473:pathology*; D004938:Esophageal Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology*; D005189:False Positive Reactions; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D008207:Lymphatic Metastasis / Q000000981:diagnostic imaging; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging / Q000379:methods*; D019275:Radiopharmaceuticals; D012189:Retrospective Studies; D014055:Tomography, Emission-Computed
D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18