This is the second most common cancer in the U.K.; the lifetime risk is about 1:20, which is doubled with a positive family history. Most t...
This is the second most common cancer in the U.K.; the lifetime risk is about 1:20, which is doubled with a positive family history.
Most tumours (90%) are in the rectosigmoid, and 60% are in the sigmoid itself.
Overall, 5-year survival is >50%.
Endorectal US is useful for distinguishing between T1 and T3 rectal tumours.
COLONOGRAPHY CT
• Overall sensitivity is about 95%.
• Nodes >1 cm or in clusters of more than three suggest malignancy.
• Check for peritoneal nodules or ascites.
MAGNETIC RESONANCE IMAGING (MRI)
• MRI is the gold standard for local staging of rectal malignancy.• Tumour has intermediate signal intensity on T2.• The closer the tumour is to the circumferential resection margin (CRM), the poorer the outcome—1.6-times more likely to have died by 5 years with tumour less than 1 mm from the CRM compared to 10 mm from the CRM.• If tumour is less than 5 mm from the CRM, evidence suggests a benefit from pre-operative (‘neoadjuvant’) chemotherapy.• Extramural vascular invasion—associated with a significantly reduced disease-free survival time.• Positron emission tomography (PET)/CT preferred for detecting disease recurrence.
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