18-F-fluorodeoxyglucose-positron emission tomography evaluation of early metabolic response during radiation therapy for cervical cancer.
OBJECTIVE
To document changes in cervical tumor (18)-F-fluorodeoxyglocose (FDG) uptake during radiation therapy and to correlate those changes with post-treatment tumor response and survival outcome.


METHODS
A total of 36 patients with Stage Ib1 to IIIb cervical cancer were enrolled in an institutional protocol examining the use of fluorodeoxyglucose-positron emission tomography (FDG-PET) for brachytherapy treatment planning. As part of this study, FDG-PET or PET/computed tomograpy (CT) images were obtained before, during, and after the completion of radiation therapy. Tumor metabolic responses were assessed qualitatively and semi-quantitatively by measurement of the maximal standardized uptake value (SUV(max)).


RESULTS
Post-treatment FDG-PET images were obtained for 36 patients in this study. Of the patients, 29 patients had a complete metabolic response on the post-treatment PET, 4 had a partial metabolic response, and 3 had new sites of FDG uptake. Six patients had a complete metabolic response observed during radiation therapy, 26 had a partial metabolic response and 4 had stable or increased tumor metabolic activity. For patients with complete metabolic response during radiation therapy, median time to complete response was 29.5 days (range, 18-43 days). The mean cervical tumor SUV(max) decreased from 11.2 (SD, 6.3; range, 2.1-38.0) pretreatment to 2.4 (SD, 2.7; range, 0-8.8) mid treatment, and 0.5 (SD, 1.7; range, 0-8.3) post-treatment.


CONCLUSIONS
During radiation therapy for cervical cancer, FDG-PET can be used to monitor treatment response. Complete metabolic response during radiation therapy was observed for a subset of patients. Recommendations regarding the optimal timing of FDG-PET during treatment for cervical cancer will require further systematic study.
Department of Radiation Oncology, Washington University School of Medicine, St. Louis, MO, USA.
Julie K
JK
Schwarz
Lillie L
LL
Lin
Barry A
BA
Siegel
Tom R
TR
Miller
Perry W
PW
Grigsby
D000328:Adult; D000368:Aged; D001918:Brachytherapy / Q000379:methods*; D002277:Carcinoma / Q000000981:diagnostic imaging / Q000473:pathology / Q000532:radiotherapy; D005260:Female; D019788:Fluorodeoxyglucose F18 / Q000493:pharmacokinetics; D006801:Humans; D008198:Lymph Nodes / Q000473:pathology; D008660:Metabolism / Q000528:radiation effects; D008875:Middle Aged; D009361:Neoplasm Invasiveness; D049268:Positron-Emission Tomography / Q000379:methods*; D011868:Radioisotopes; D012044:Regression Analysis; D002583:Uterine Cervical Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology / Q000532:radiotherapy*
D011868:Radioisotopes; D019788:Fluorodeoxyglucose F18