الفهرس 
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Abstract
Primary carcinoma of the esophagus accounts for approximately 7% of all gastrointestinal malignancies. More than 90% of esophageal cancers are either 60% squamous cell carcinomas or 30% adenocarcinomas.
The most common presenting symptoms of esophageal cancer are dysphagia and weight loss. At the time of the diagnosis of esophageal cancer, >50% of patients have either unresectable tumors or radiographically visible metastases.
Patients with esophageal carcinoma have a poor prognosis. Although it is a disease that can be treated, it can rarely be cured.
Dual modality PET/CT scanning provides accurately fused morphologic (CT) and functional (PET) data sets. A very small tumor is well detected by PET but can be missed by CT. On the other hand, a large tumor with minimal functional deviations may be seen on a CT image, put may not be detected by PET. In both situations, PET/CT would localize the tumor accurately.
FDG-PET can detect esophageal cancer before it becomes evident on CT, but PET is limited in its ability to determine the extent of tumor spread though the esophageal wall or tumor invasion of adjacent structures.
Cancer of the esophagus is most often diagnosed by endoscopic biopsy or brushing and the size, location, and morphology of the tumor are evaluated by endoscopy and barium esophagography. However, PET/CT must be prior to endoscopic intervention to be more accurate and less prone to false-positive findings.
Once the diagnosis of esophageal cancer has been made, staging is the next critical step in determining the most appropriate treatment plan for the patient.
The major advantage of PET/CT is its ability to detect distant metastases to facilitate treatment planning because these patients are no longer eligible for surgical resection however, it is best to evaluate postsurgical patients at least 6 weeks after surgery.
PET/CT can improve the accuracy in distinguishing recurrent disease from benign posttherapy changes (scar), delineating the anatomic location of metastatic disease, and monitoring therapy response.
PET/CT can also evaluate early prediction of treatment response within the first 2 weeks of treatment and late prediction 3 weeks after completion of treatment because SUV ≥ 4 is the strong predictor of short-term survival and poor outcome. However PET/CT cannot differentiate between minimal residual disease and local recurrence. Therefore esophagectomy should remain an option even if PET/CT is normal after therapy.
In addition, PET/CT occasionally allows detection of unsuspected synchronous neoplasms, most commonly in the stomach, head and neck, and colon.
The major limitation of FDG PET with regard to the visualization of the anatomic extent of the primary mass and preclude evaluation of the depth of local tumor invasion also, detection of nodal metastases adjacent to the primary tumor due to its relatively poor spatial resolution which reduces sensitivity. Generally, endoscopic (EUS) is regarded as superior in locoregional assessment of disease.