History

From the list of symptoms discussed, a physician can roughly suspect whether a patient has CRC and whether to proceed with further investigations.  The physician can also determine whether the patient is a low or high risk individual.

Physician Examination

Important signs to look for:

1. Significant anaemia
2. Significant weight loss
3. Swollen lymph nodes in the left neck
4. Abdominal lump
5. A lump on digital rectal examination

Investigations that are essential to diagnose a patient with CRC include:

1. Colonoscopy.  In addition to diagnosing a CRC it can also check the entire length of the colorectum for a second cancer or the presence of polyps. At the same time a cancer can be biopsied for histology and polyps can be removed.
   
   
2. Double contrast barium enema x-ray.  Accuracy is equivalent to that of colonoscopy but lesions found cannot be biopsied or removed via this method.
   
   
3. CT scan abdomen.  This expensive computerized x-ray scan can reveal internal organs and intestines in very good detail. It is especially useful for determining the actual extent and location of the tumour, invasion of adjacent organs or bowels and the presence of liver metastases. An alternative to CT scan is an ultrasound scan which is cheaper. Ultrasound Scan is accurate for diagnosing liver metastases.
   
   
4. Tumour markers are substances found in the blood that are specific for a type of cancer. For CRC, the tumour marker is carcino-embryonic antigen (CEA) i.e. patients with CRC may have a high level of CEA. CEA is useful in monitoring patients for recurrence after surgery.
   
   
5. Biopsy of tumour.  A diagnosis of cancer is based on a biopsy of the tumour. In this procedure a piece of the tumour is removed and sent to the laboratory where it is examined under the microscope.