After definitive treatmetn of colon cancer, patients are followed with CEA levels. When they begin to rise, a recurrence is suspected. PET is being more frequenlty used to detect and identify recurrence in this situation. More recently NCCN has been more supportive of PET in this setting. It used to support PET only in the situation of rising CEA and no identified recurrence for localization of disease recurrence in patients with rising CEA level and non-diagnostic CT scans. However, PET scan can potentially identify occult disease in this setting that CT may miss. Therefore, PET scans can led to more potentially curative resection in patients with elevated CEA and patients who are candidates for resection of isolated colorectal cancer liver metastases. PET scan prior to attempted resection also reduces the number of unnecessary surgeries.
On p. Col-9, 2012 NCCN recommends the use of CT scans of chest and abdomen in the situation of serial CEA elevations but also says “Consider PET/CT scan”.
CMS guidelines state that PET would rarely be used in the diagnosis of colorectal cancer. However, starting July 1, 2001, HCFA, now called the Centers for Medicare and Medicaid Services (CMS), is covering FDG-PET imaging for diagnosis, staging, and restaging of colorectal cancer.
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