Staging and prognosis of bowel cancer

Staging bowel cancer

The tests completed by your specialist help show whether you have bowel cancer and whether it has spread from the original site to other parts of the body. Working out how far the cancer has spread is called staging and it helps your health care team decide the best treatment for you.

In Australia, there are two main systems used for staging bowel cancer:

• the Australian Clinico-Pathological Staging (ACPS) system
• the TNM staging system – TNM stands for tumour–nodes–metastasis. Each letter is assigned a number to show how advanced the cancer is.

Your doctor will combine the results of your early tests, as well as the tests on the cancer tissue and lymph nodes removed during surgery, to work out the overall stage of the cancer:

• stage I (ACPS A) – tumours are found only in the lining of the bowel (early or limited disease)
• stage II (ACPS B) – tumours have spread deeper into the layers of the bowel walls (locally advanced disease)
• stage III (ACPS C) – cancer has spread to nearby lymph nodes (locally advanced disease)
• stage IV (ACPS D) – tumours have spread beyond the bowel to other parts of the body, such as the liver or lungs, or to distant lymph nodes (advanced or  metastatic disease).

In general, earlier stages have better outcomes. Almost 50% of bowel cancers in Australia are diagnosed at stages I and II. If you are finding it hard to understand staging, ask someone in your medical team to explain it in a way that makes sense to you.

Molecular testing

If you are diagnosed with advanced bowel cancer, your doctor may order extra tests on the biopsy sample to look for particular features that can cause the cancer cells to behave differently. These tests may look for mutations in the RAS and BRAF genes or features in the cancer cells suggesting that further genetic testing is required. Knowing whether the tumour has one of these features may help your treatment team determine suitable treatment options.

Prognosis

Prognosis means the expected outcome of a disease. You may wish to discuss your prognosis and treatment options with your doctor, but it is not possible for any doctor to predict the exact course of the disease. Instead, your doctor can give you an idea about the general prognosis for people with the same type and stage of cancer.

Generally, the earlier that bowel cancer is diagnosed, the better the chances of successful treatment. If cancer is found after it has spread beyond the bowel to other parts of the body, it may still respond well to treatment and can often be kept under control.

Test results, the type of cancer, the rate and depth of tumour growth, the likelihood of response to treatment, and factors such as your age, level of fitness and medical history are important in assessing your prognosis. These details will also help your doctor advise you on the best treatment options.