PET in Colorectal Cancer

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PET in Colorectal Cancer
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Indications for FDG PET

• Rising marker, (-) CT/MRI
• Nonspecific findings on CT/MRI,
• recurrence or post treatment changes?
• Known metastases evaluate extent or
• disease or identify other sites of recurrence
• Evaluate response to chemotherapy

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PET-FDG SCAN IN RECTAL CA
191642
LV
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Coronal
MSKCC
AL361200
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Comparison of PET and CT
N40 pts. (93 biopsies)
WPET0.97/-.02
Plt.001
WCT0.73/-.06
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Biopsy Correlated Finding
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Diagnostic Imaging in Oncology

• Detection
• Differential Diagnosis
• Tumor biology relevant to therapy
• Staging
• Recurrence
• Response

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PET in Colorectal Cancer

• PET accuracy between 88 - 92 gt CT (75)
• Among pt.s with suspected recurrence, SUV gt 3.5
  has a 90 probability of tumor, and a 10 prob of
  being a benign lesion
• Most common reasons for missing lesions is size
  (lt 1 cm in diameter), location (peritoneum), and
  artifact (lesion near high count area)
• PET gtgt CT for Rx response in rectal Ca