Colorectal cancer is a cancer that affects the colon and the rectum of the large intestine. Cancer stages are used to describe how much the cancer has spread. Cancer in earlier stages is limited to a local area or region (locoregional). Cancer in later stages often spreads to other parts of the body (metastasized). Colorectal cancer staging is important in choosing the correct treatment plan.
For staging of locoregional rectal cancer, pelvic transrectal ultrasound, pelvic MRI without and with intravenous (IV) contrast, and pelvic MRI without IV contrast are usually appropriate. These tests may be done together. Abdominal and pelvic CT with IV contrast, CT colonography, and FDG-PET/CT may be appropriate.
For locoregional rectal cancer staging after neoadjuvant (initial) treatment, pelvic MRI without and with IV contrast and pelvic MRI without IV contrast are usually appropriate. Abdominal and pelvic CT with IV contrast and FDG-PET/CT may be appropriate.
For staging of metastasized colorectal cancer, either chest, abdominal, and pelvic CT with IV contrast or chest CT with IV contrast combined with abdominal and pelvic MRI with IV contrast are usually appropriate. Chest, abdominal, and pelvic CT without IV contrast, abdominal and pelvic MRI without IV contrast, and FDG-PET/CT may be appropriate.
For more information, see the Colorectal Cancer page.