Time course of tumor metabolic activity during chemoradiotherapy of esophageal squamous cell carcinoma and response to treatment.
OBJECTIVE
To evaluate the time course of therapy-induced changes in tumor glucose use during chemoradiotherapy of esophageal squamous cell carcinoma (ESCC) and to correlate the reduction of metabolic activity with histopathologic tumor response and patient survival.


METHODS
Thirty-eight patients with histologically proven intrathoracic ESCC (cT3, cN0/+, cM0) scheduled to undergo a 4-week course of preoperative simultaneous chemoradiotherapy followed by esophagectomy were included. Patients underwent positron emission tomography with the glucose analog fluorodeoxyglucose (FDG-PET) before therapy (n = 38), after 2 weeks of initiation of therapy (n = 27), and preoperatively (3 to 4 weeks after chemoradiotherapy; n = 38). Tumor metabolic activity was quantitatively assessed by standardized uptake values (SUVs). Results Mean tumor FDG uptake before therapy was 9.3 +/- 2.8 SUV and decreased to 5.7 +/- 1.9 SUV 14 days after initiation of chemoradiotherapy (-38% +/- 18%; P <.0001). The preoperative scan showed an additional decrease of metabolic activity to 3.3 +/- 1.1 SUV (P <.0001). In histopathologic responders (< 10% viable cells in the resected specimen), the decrease in SUV from baseline to day 14 was 44% +/- 15%, whereas it was only 21% +/- 14% in nonresponders (P =.0055). Metabolic changes at this time point were also correlated with patient survival (P =.011). In the preoperative scan, tumor metabolic activity had decreased by 70% +/- 11% in histopathologic responders and 51% +/- 21% in histopathologic nonresponders.


CONCLUSIONS
Changes in tumor metabolic activity after 14 days of preoperative chemoradiotherapy are significantly correlated with tumor response and patient survival. This suggests that FDG-PET might be used to identify nonresponders early during neoadjuvant chemoradiotherapy, allowing for early modifications of the treatment protocol.
Department of Nuclear Medicine, Klinikum rechts der Isar, Technische Universitaet Muenchen, Ismaningerstrasse 22, D-81675 Munich, Germany. h@wieder.de
Hinrich A
HA
Wieder
Björn L D M
BL
Brücher
Frank
F
Zimmermann
Karen
K
Becker
Florian
F
Lordick
Ambros
A
Beer
Markus
M
Schwaiger
Ulrich
U
Fink
Jörg Rüdiger
JR
Siewert
Hubert J
HJ
Stein
Wolfgang A
WA
Weber
D000368:Aged; D002294:Carcinoma, Squamous Cell / Q000000981:diagnostic imaging* / Q000378:metabolism / Q000401:mortality / Q000628:therapy*; D017024:Chemotherapy, Adjuvant; D003131:Combined Modality Therapy; D018572:Disease-Free Survival; D004938:Esophageal Neoplasms / Q000000981:diagnostic imaging* / Q000378:metabolism / Q000401:mortality / Q000628:therapy*; D016629:Esophagectomy / Q000379:methods; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D011300:Preoperative Care / Q000379:methods; D011379:Prognosis; D011446:Prospective Studies; D018714:Radiotherapy, Adjuvant; D018570:Risk Assessment; D012680:Sensitivity and Specificity; D016019:Survival Analysis; D014055:Tomography, Emission-Computed; D016896:Treatment Outcome
D019788:Fluorodeoxyglucose F18