Article
Early assessment of response during neoadjuvant radiochemotherapy in esophageal squamous cell carcinoma patients by 18-FDG-PET: individualized therapy ?
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Published: | March 20, 2006 |
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Purpose: Positron emission tomography with the glucose analog [18F]-fluorodeoxyglucose (FDG-PET) has been used for response evaluation in patients with esophageal squamous cell carcinoma (ESCC) and neoadjuvant radiochemotherapy (RTx/CTx). This prospective study was undertaken to compare FDG-PET assessment of tumor response during RTx/CTx with histopathology in patients with ESCC, and to correlate the findings with survival.
Patients and Methods:Sixty-one patients with histologically proven ESCC (cT3, cN0/+, cM0) underwent preoperative, simultaneous RTx/CTx followed by esophagectomy between 1996 and 2004. The patients underwent FDG-PET prior to and 2 weeks after the begin of RTx/CTx (20Gray). Histopathological response was quantified as the percentage of residual tumor cells. The threshold pre-therapy-to-during-therapy decrease in standardized uptake value by FDG-PET used to define metabolic responders (∆SUVR) was –30%.
Results:Receiving-operator-curve analysis (ROC) for determination of metabolic response revealed an area-under-curve (AUC) of 7140 (p=0.005) with a sensitivity of 76%, specificity (70%), a positive predictive value of 81% and a negative predictive value of 64% (p<0.0001). Responder by FDG-PET during the neoadjuvant treatment (p=0.016) as well as Histopathology (p<0.0001) showed substantially better survival compared to nonresponders.
Conclusions: Changes in tumor metabolic activity by FDG-PET during neoadjuvant RTx/CTx allows an accurate determination of response due to the multimodal approach in patients with ESCC. This stratification may lead to a change of the neoadjuvant into a definitive therapy concept in nonresponders (individualized tumor therapy).