Question
Positron Emission Tomography (PET) used in Preoperative staging of Gastroesophageal tumours is to detect:
| A. |
Distant metastatic disease
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| B. |
Extension into stomach
|
| C. |
Local spread
|
| D. |
Lymph node status
|
Show Answer
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Correct Answer � A
Explanation
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Positron Emission Tomography (PET) is a highly sensitive imaging modality used in cancer staging. It detects areas of increased metabolic activity, such as those seen in malignancies, by using fluorodeoxyglucose (FDG), a radioactive tracer.
Role of PET in Gastroesophageal Tumors
- Primary Purpose:
- To detect distant metastatic disease (e.g., liver, lungs, or bones).
- This information is critical because the presence of distant metastases often precludes surgical intervention.
Reason to rule out other options:
B. Extension into stomach:
-
- Local extension into the stomach is better evaluated with endoscopic techniques, such as endoscopic ultrasonography (EUS) or contrast-enhanced CT scan.
C. Local spread:
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- PET has limited sensitivity for evaluating local invasion or adjacent structure involvement. Techniques like EUS and CT are superior for assessing local spread.
D. Lymph node status:
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- Although PET can detect metabolically active lymph nodes, it is not the most reliable tool. False positives may occur due to reactive lymph nodes, and false negatives due to small metastatic nodes.
