The disease may have progressed to other parts of the body, such as the liver or lungs, in stage 4 colon cancer. This stage is broken into two parts: 4A and 4B. Colon cancers in stage 4 have progressed from the colon to other organs, such as the liver. The cancer can also spread to the lungs, brain, and the peritoneum, which is the lining of the abdominal cavity.

Stage 4A

  • Any T: The cancer may or may not have spread beyond the colon or rectum wall.
  • Any N: The cancer could have migrated to adjacent lymph nodes or not.
  • M1a: The cancer has spread to one distant organ, such as the liver or lungs, or to a distant collection of lymph nodes, but not to distant sections of the peritoneum, the abdominal cavity's lining.

Stage 4B

  • Any T: The cancer may or may not have spread beyond the colon or rectum wall.
  • Any N: The cancer could have migrated to adjacent lymph nodes or not.
  • M1b: The cancer has spread to more than one distant organ, such as the liver or lungs, or to a distant collection of lymph nodes, but not to distant sections of the abdominal cavity's lining.

Stage 4C

  • Any T: The cancer may or may not have spread beyond the colon or rectum wall.
  • Any N: The cancer could have migrated to adjacent lymph nodes or not.
  • M1c: The malignancy has spread to distal sections of the peritoneum (abdominal cavity lining), and it may or may not have migrated to distant organs or lymph nodes.

Treatment

  • Surgery is quite rare in the event of stage 4 colon cancer. Surgery may be performed in cases where the cancer has progressed to only a few sites of the liver or lungs. Surgery has the potential to extend a person's life and possibly cure them. During surgery, the cancer-affected part of the colon, as well as adjacent lymph nodes and other locations where the cancer has spread, are removed.
  • Chemotherapy can be given before or after surgery. When cancer has progressed to the liver, hepatic artery infusion may be used. A hepatic artery infusion is a treatment that involves injecting chemotherapy directly into the hepatic artery.

If the tumours are too large to be removed, chemotherapy may be administered first, and if the tumour reduces, surgery to remove the tumour may be performed. If the tumour is obstructing the intestines, surgery may be required.

  • During a colonoscopy, a stent, which is a hollow metal or plastic tube, can be inserted into the colon to prevent surgery. If this is not the case, surgeries such as a colostomy may be required.

Colon cancer that has spread to other regions of the body requires special treatment.

The spread of cancer cells to other organs is known as metastasis. This is prevalent in people with advanced colon cancer who have disseminated the disease to other organs such as the liver, lungs, brain, and peritoneal cavity (the lining of the abdominal cavity). Apart from chemotherapy, which is recognised to be the primary treatment for metastatic colon cancer, treatments such as radiation therapy and targeted therapy can also be offered.

Stage 4 colon cancer prognosis

The 5-year survival rate for people with metastatic or stage four colon cancer is only 12%.