With stage IV colon cancer, the cancerous tissue is no longer contained to your large intestines. Metastasis has caused the abnormal cells to affect other organs of the body, such as the liver, ovaries, lungs and peritoneum (protective lining within your abdomen). While many people still respond well to surgery, the severity of the metastasis could make the cancer inoperable in this stage of the disease, limiting the options for treatment.
As with almost any other form of cancer, the best method of treatment relies on a number of factors, including your health, area of metastasis, rate of metastasis, amount of metastasis and size of tumours. In stage IV inoperable colon cancer, you're usually dealing with either sizeable tumours or an abundance of tumours, so your doctor will determine the best treatment option for you. However, it usually entails a primary course of ablation, which is essentially the removal of tissue through freezing, heating or other means of dissolving cells, and then followed by an adjuvant course of therapy. When the term "adjuvant" is used to describe treatment, it simply means following the primary course of care.
One of the more common non-surgical methods of therapy for this stage of the disease is cryotherapy. Often referred to as cryoablation, an instrument known as a cryoprobe is guided into the cavity or organ containing the malignant growth. When the probe comes into contact with the tumour, it's frozen with liquid forms of either nitrogen or carbon dioxide, destroying the abnormal cells. Once the tumour thaws, the body simply reabsorbs the dead tissue. This can work with both sizeable tumours and an abundance of tumours.
If cryosurgery isn't an option, you may benefit from microwave ablation. And muck like cryotherapy, a tube is guided into the cavity or organ containing the malignant growth. But instead of liquid nitrogen or liquid carbon dioxide to freeze the tumour, microwaves are emitted through a needle directly into the malignancy to heat and destroy the abnormal cells.
In either of these treatment methods, you'll go through anywhere from a single to several sessions, depending on your body's response to treatment and amount of metastasis. Side effects vary from person to person, but may include pain, discomfort, cramping, bleeding and a loss of sensation near the administration site.
While both cryoablation and microwave ablation can go a long way to treating stage IV inoperable colon cancer, adjuvant therapy is often necessary to further reduce the size or abundance of cancerous cells. Doctors most often rely on chemotherapy in conjunction with ablation, but you may instead receive a course of radiation therapy.
With chemotherapy, you'll receive localised treatment, systemic treatment or a combination of both. In localised chemotherapy, anti-cancer drugs are administered into a vein that leads directly to the organ suffering metastasis, such as the liver. This only treats the cancer residing in that organ. Any other areas of metastasis aren't receiving chemo drugs, and thereby may continue to grow. This is why systemic chemotherapy is often employed at the same time. Systemic treatment sends the anti-cancer drugs throughout the body to shrink and kill any abnormal cells. Chemotherapy can trigger the side effects of nausea, vomiting, constipation, diarrhoea, fatigue, hair loss and anaemia.
Radiation therapy uses ionised energy to destroy and kill cancerous cells by altering their DNA. Treatments are directed within areas of metastasis as well as the colon itself, so a number of sessions may be necessary to fully shrink the tumours. This may cause the side effects of nausea, vomiting, diarrhoea, fatigue, urinary problems, inflammation and skin irritation (along administration site) and bleeding.