Bldm. Brucher et al., Neoadjuvant therapy of esophageal squamous cell carcinoma: Response evaluation by positron emission tomography, ANN SURG, 233(3), 2001, pp. 300-309
Objective To evaluate the use of positron emission tomography using [F-18]-
fluorodeoxyglucose (FDG-PET) to assess the response to neoadjuvant radiothe
rapy and chemotherapy in patients with locally advanced esophageal cancer.
Summary Background Data Imaging modalities, including endoscopy, endoscopic
ultrasound, computed tomography, and magnetic resonance imaging, currently
used to evaluate response to neoadjuvant treatment in esophageal cancer do
not reliably differentiate between responders and nonresponders.
Methods Twenty-seven patients with histopathologically proven squamous cell
carcinoma of the esophagus, located at or above the tracheal bifurcation,
underwent neoadjuvant therapy consisting of external-beam radiotherapy and
5-fluorouracil as a continuous infusion. FDG-PET was performed before and 3
weeks after the end of radiotherapy and chemotherapy (before surgery). Qua
ntitative measurements of tumor FDG uptake were correlated with histopathol
ogic response and patient survival.
Results After neoadjuvant therapy, 24 patients underwent surgery. Histopath
ologic evaluation revealed less than 10% viable tumor cells in 13 patients
(responders) and more than 10% viable tumor cells in 11 patients (nonrespon
ders). In responders, FDG uptake decreased by 72% +/- 11%; in nonresponders
, it decreased by only 42% +/- 22%. At a threshold of 52% decrease of FDG u
ptake compared with baseline, sensitivity to detect response was 100%, with
a corresponding specificity of 55%. The positive and negative predictive v
alues were 72% and 100%. Nonresponders to PET scanning had a significantly
worse survival after resection than responders.
Conclusion FDG-PET is a valuable tool for the noninvasive assessment of his
topathologic tumor response after neoadjuvant radiotherapy and chemotherapy
.