Early metabolic response evaluation by fluorine-18 fluorodeoxyglucose positron emission tomography allows in vivo testing of chemosensitivity in gastric cancer: long-term results of a prospective study.
OBJECTIVE
We prospectively evaluated the predictive value of positron emission tomography using fluorine-18 fluorodeoxyglucose (FDG-PET) for in vivo testing of chemosensitivity in locally advanced gastric cancer using an a priori definition of metabolic response (a decrease of >35% of the standard uptake value). The goal of the study was the definition of biologically different groups of patients prior to or early during induction therapy, with special emphasis on FDG non-avid tumors.


METHODS
Based on our data, which was published in 2003, at least 36 patients with metabolic response or FDG non-avid tumors had to be recruited for an analysis of the group of FDG non-avid tumors with sufficient statistical power. Seventy-one patients (32 metabolic nonresponders, 17 metabolic responders, and 22 patients with FDG non-avid tumors) underwent FDG-PET at baseline. In FDG-avid tumors, FDG-PET was repeated 14 days after the initiation of chemotherapy.


RESULTS
Metabolic responders (17 of 49) showed a high histopathologic response rate (69%) and a favorable prognosis (median survival not reached), whereas metabolic nonresponders (32 of 49) had a poor prognosis (median survival, 24.1 months) and showed a histopathologic response in 17%. The histopathologic response rate (24%) for FDG-PET non-avid patients showed no significant difference compared with FDG-avid nonresponders (P=0.72). Survival of FDG non-avid patients was 36.7 months (not significantly different from FDG-avid nonresponders, 24.1 months, P=0.46).


CONCLUSIONS
In locally advanced gastric cancer, three different metabolic groups exist. Response and survival was predicted by PET in FDG-avid tumors. Metabolic response assessment was not possible in FDG non-avid tumors; however, due to unfavorable outcome, therapy modification might also be considered in FDG non-avid tumors.
Ott
Katja
K
Department of Surgery, Technische Universität München, Munich, Germany.
Herrmann
Ken
K
Lordick
Florian
F
Wieder
Hinrich
H
Weber
Wolfgang A
WA
Becker
Karen
K
Buck
Andreas K
AK
Dobritz
Martin
M
Fink
Ulrich
U
Ulm
Kurt
K
Schuster
Tibor
T
Schwaiger
Markus
M
Siewert
Jörg-Rüdiger
JR
Krause
Bernd J
BJ
D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use; D019008:Drug Resistance, Neoplasm; D005260:Female; D019788:Fluorodeoxyglucose F18 / Q000378:metabolism; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D049268:Positron-Emission Tomography; D011237:Predictive Value of Tests; D011379:Prognosis; D011446:Prospective Studies; D019275:Radiopharmaceuticals / Q000378:metabolism; D013274:Stomach Neoplasms / Q000000981:diagnostic imaging* / Q000188:drug therapy / Q000401:mortality; D013995:Time
D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18