So, to start with. If you are looking for stage 4 cancer you must be having an idea of what is cancer. If told in one line, cancer is uncontrolled proliferation of cells in the body. It may be from any site or organ of body.
Here we discuss the stage 4 colon cancer.
What is Stage 4 Colon Cancer?
Many checkpoints are there by the body’s defense system due to which even if uncontrolled growth happens in a cell or a group of cells, it may be halted at further steps. Only after evading multiple checkpoints, a cell becomes cancerous. Now even if colon cancer develops in an individual, it may be in early stages and if detected on time, may be controlled or cured completely.
But sometimes, colon cancer cells migrate from their original site and and travel through blood to get lodged at other sites of the body. This is called as metastatic disease or stage 4 colon cancer.
Symptoms of Stage 4 Colon Cancer
The symptoms of metastatic disease will depend on the site of metastasis and on the site of origin. Depending on the site of metastasis, the symptoms of stage 4 cancer may be as follows-
Colon Cancer spread to Lungs
It may be the involvement of lung parenchyma or pleural membrane, leading to pleural effusion. It may cause symptoms such as cough, breathlessness, chest pain, etc. Lung metastasis are more commonly multiple than single, and bilateral than unilateral.
Diagnostic investigations to pickup lung metastasis is X ray chest, and more specifically Ct scan of chest, where they appear as ground glass opacities. However, other causes must be ruled out like tuberculosis, primary lung malignancy, infections, sarcoidosis, etc.
Colon Cancer spread to Liver
Liver is also a common site of metastasis from other organs. Liver involvement by colon cancer spread may cause symptoms like jaundice, right upper abdominal discomfort, abdominal distention, etc. Liver function test may also be deranged with raised bilirubin, alkaline phosphatase, GGT, etc. Liver metastasis are also multiple more commonly than solitary and may involve both lobes of liver.
Colon Cancer spread to Brain
Spread of colon cancer to brain may lead to symptoms depending on site of brain involvement, size and number of metastasis. Most common symptoms are headache, vomiting or nausea, mental changes, memory problems, seizures, and/or dizziness.
They are more common located in the watershed arterial zone at grey white matter junction. Usually there is a zone of peritumoural oedema out of proportion with the tumor size. Other lesions like tuberculosis, abscesses, toxoplasmosis, fungal infections, etc may present as brain SOLs and should be ruled out. MRI of brain should be done if we are suspecting brain metastasis in an individual.
Colon Cancer spread to Bones
Spread of colon cancer to bone may lead to bone pain, fracture from minor trauma, spinal cord compression leading to lower limb weakness, urinary incontinence, bowel incontinence etc. Any bone may be involved but most commonly affected are spine, pelvis and thigh bones.
Other site of metastasis may be peritoneum, omentum, adrenal gland, or other organs.
Stage 4 Colon Cancer Prognosis
Prognosis of stage 4 colon cancer depends on other factors like number of metastatic sites involved, extent of the metastasis, performance status of the patient, presence of genetic mutations and whether the patient has resectable or unresectable stage 4 colon cancer.
Resectable stage 4 disease includes cases that may be amenable to curative modalities like surgery, ablation, embolisation or radiation therapy. These include cases with limited lung and/or liver metastasis.
As you can see in the figure above, the colon cancer has spread to liver such that it may treated with a curative intent. Similarly it may present with limited lung metastasis.
In such cases, the prognosis of the disease may be improved with curative resection of the tumor. Even in cases that are unresectable upfront, but after chemotherapy and/or targeted therapy become resectable, these options may be tried.
But if there if widespread metastasis to one or more site and disease is grossly unresectable or the patient is otherwise not a candidate for curative resection, then the treatment is done with a palliative intent and the prognosis is poor in such cases.
Survival/Life Expectancy with Stage 4 Colon Cancer
The median 5 year survival in stage 4 or metastatic disease is overall low as compared to earlier stages of disease. Also, it depends on the burden of metastatic disease and the number of sites involved, along with other factors.
Also, if there is a limited metastasis of colon cancer to lungs and/or liver, and patient could undergo surgery, ablation, embolization or radiation with a curative intent, the survival may be better.
Otherwise, the median 5 year survival for stage 4 colon cancer is close to 14%.
Treatment of Stage 4 Colon Cancer
The treatment of metastatic disease depends on the number and extent of metastatic sites involved, molecular/genetic mutations, performance status of the patient, along with other factors.
The various modalities that may be used for treatment of metastatic disease include-
- Targeted Therapy
Other modalities that may be used for palliation or relied of symptoms include-
- Radiation Therapy
- Bone Directed Therapy