Limited predictive value of FDG-PET for response assessment in the preoperative treatment of esophageal cancer: results of a prospective multi-center trial (SAKK 75/02).
BACKGROUND
Only responding patients benefit from preoperative therapy for locally advanced esophageal carcinoma. Early detection of non-responders may avoid futile treatment and delayed surgery.


METHODS
In a multi-center phase ll trial, patients with resectable, locally advanced esophageal carcinoma were treated with 2 cycles of induction chemotherapy followed by chemoradiotherapy (CRT) and surgery. Positron emission tomography with 2[fluorine-18]fluoro-2-deoxy-d-glucose (FDG-PET) was performed at baseline and after induction chemotherapy. The metabolic response was correlated with tumor regression grade (TRG). A decrease in FDG tumor uptake of less than 40% was prospectively hypothesized as a predictor for histopathological non-response (TRG > 2) after CRT.


RESULTS
45 patients were included. The median decrease in FDG tumor uptake after chemotherapy correlated well with TRG after completion of CRT (p = 0.021). For an individual patient, less than 40% decrease in FDG tumor uptake after induction chemotherapy predicted histopathological non-response after completion of CRT, with a sensitivity of 68% and a specificity of 52% (positive predictive value 58%, negative predictive value 63%).


CONCLUSIONS
Metabolic response correlated with histopathology after preoperative therapy. However, FDG-PET did not predict non-response after induction chemotherapy with sufficient clinical accuracy to justify withdrawal of subsequent CRT and selection of patients to proceed directly to surgery.
Klaeser
Bernd
B
Department of Nuclear Medicine, Inselspital Bern, Switzerland. bernd.klaeser@insel.ch
Nitzsche
Egbert
E
Schuller
Jan C
JC
Köberle
Dieter
D
Widmer
Lucas
L
Balmer-Majno
Sabine
S
Hany
Thomas
T
Cescato-Wenger
Corinne
C
Brauchli
Peter
P
Zünd
Michael
M
Pestalozzi
Bernhard C
BC
Caspar
Clemens
C
Albrecht
Susanne
S
von Moos
Roger
R
Ruhstaller
Thomas
T
D000328:Adult; D000368:Aged; D004938:Esophageal Neoplasms / Q000000981:diagnostic imaging* / Q000628:therapy*; D005260:Female; D019788:Fluorodeoxyglucose F18; D005858:Germany; D006801:Humans; D008297:Male; D008875:Middle Aged; D049268:Positron-Emission Tomography / Q000379:methods*; D011300:Preoperative Care; D011379:Prognosis; D011446:Prospective Studies; D019275:Radiopharmaceuticals; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013557:Switzerland; D016896:Treatment Outcome
D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18