Pathology and staging of colorectal cancer

Pathology refers to the careful examination of tissue under a microscope in order to find out whether it's cancerous or non-cancerous and to determine the type of tumour it is. Different types of tumours can affect the colon and rectum.

Benign tumours

Benign tumours are non-cancerous growths that do not spread to other parts of the body and are not usually life-threatening:

• colorectal polyps

Precancerous conditions

Precancerous conditions have the potential to develop into cancer:

• adenomatous polyps (adenomas)
• polyposis syndromes
  • familial adenomatous polyposis (FAP)
  • hereditary non-polyposis colon cancer (HNPCC)

Malignant tumours

Malignant tumours are cancerous growths that have the potential to metastasize (spread to other parts of the body):

• adenocarcinoma
• rare malignant colorectal tumours
  • carcinoid tumours
  • lymphoma
  • sarcoma
  • gastrointestinal stromal tumour (GIST)
  • adenosquamous cell carcinoma
  • squamous cell carcinoma
  • small cell carcinoma (oat cell carcinoma)
  • medullary carcinoma
  • melanoma

Once the type of tumour has been diagnosed, the doctor will also consider:

• the grade of the tumour (how abnormal the cancer cells look and behave)
• the stage of the cancer (how far the cancer has progressed) and if it has spread
• prognostic factors (special characteristics that might influence the course of the disease)
• survival statistics for the particular type and stage of cancer

All of this information helps the doctor make a treatment plan.

See a list of questions to ask your doctor about pathology and staging.