Symptoms
Depending on the location of the metastases, different symptoms can occur. In liver metastases the symptoms are very unspecific. Often the symptoms also appear later in the course of the disease.
There may be a general weakness with loss of appetite and weight loss. In general, the liver metastases are not yet painful. Depending on where the metastases are located in the liver, the skin may turn yellow (jaundice), as the bile pigment in the liver is then no longer broken down properly.
Lung metastases are unlikely to cause any clear symptoms. Lung metastases are more likely to be discovered by chance during X-ray examinations. Often the metastases are located in the peripheral area of the lung.
Occasionally they can cause symptoms such as coughing attacks or pneumonia. Coughing up blood can also occur in the context of lung metastases, but this is not necessarily the case. Symptoms of brain metastases only appear at a very advanced stage.
Only in these advanced stages do the symptoms become apparent or when the metastases are located in central areas of the brain. Often, unspecific symptoms are initially more likely to occur, which are triggered by the increased intracranial pressure. This can lead to headaches, nausea and supposed circulatory problems with dizziness.
The headaches usually last for a long period of time and do not respond well to pain medication. In general, however, these cerebral pressure signs are very unspecific and do not necessarily indicate brain metastases! In advanced cases, brain metastases can also lead to epileptic seizures, sudden paralysis or speech disorders.
Since metastases in the brain are generally rare in colorectal cancer, these advanced symptoms are also rather rare. Bone metastases also do not cause really clear symptoms. Warning signals would be, for example, pain in the back, arms or legs or even bone fractures that have no clear explanation.
Depending on the location and spread of the metastases, i.e. if they press on nerves, for example, this can lead to sensory disturbances such as tingling or numbness. If the metastases are located in the vertebral bodies of the spine, paralysis or disturbances of the intestinal and bladder function can occur. As with brain metastases, bone metastases are rare in colorectal cancer and occur in very late stages of the disease!
The intestine is connected to a dense network of lymph vessels that serve to transport the fluid that cannot be removed through the veins. In the gastrointestinal tract, protein-fat complexes are still present in the lymph. Fats taken in with food are therefore absorbed into the body via the lymph.
In the course of the lymph vessels there are lymph nodes that filter the lymph and serve to defend against disease. Degenerated cells, i.e. cancer cells, tend to break out of the cell structure. Individual cells can thus be transported away through the lymph vessels.
However, they often get stuck in the first lymph nodes, as these act as a kind of filter. Since the cancer cells do not die and can multiply very quickly, they settle in the lymph nodes and multiply. The lymph nodes become larger and firmer.
When bowel cancer is removed, a large number of lymph nodes must always be removed to ensure that there are no cancer cells in them. Only if this is the case can we speak of a complete removal. Metastases in the bones occur comparatively late.
However, colorectal cancer patients survive longer and longer due to better treatment, and so it happens that bone metastases also develop in an increasing number of colorectal cancer patients. The metastases are problematic because they weaken the bone structure and fractures occur more frequently, which further impairs the quality of life. If metastases occur in the skeleton, life expectancy is shorter compared to colorectal cancer without bone metastases.
The treatment of bone metastases can be attempted by means of chemotherapy. At 15%, lung metastases are the second most common metastases in colorectal cancer after liver metastases. The method of choice for the treatment of lung metastases is surgical removal.
Surgical removal makes sense if the colon cancer can also be removed. In addition, the metastases in the lung must be accessible for surgery. In the meantime, other methods, such as a laser, can be used to remove metastases that are difficult to reach without damaging the surrounding tissue too much.
Another option for non-operable lung metastases is chemotherapy. Liver metastases are the most common form of metastasis in colorectal cancer. The reason for the frequency of liver metastases is the outflow of blood from the intestine.
The blood from the intestine is channelled via the portal vein into the liver so that food components taken in can be processed here and harmful substances can be processed. Through this direct connection between the intestine and the liver, cancer cells can reach the liver relatively easily and unhindered and settle here. This can be a single metastasis or a widespread metastasis that affects the entire liver.
The function of the liver may be normal for a long time. The blood values that provide information about the function of the liver can also be normal for a long time. Colonisation of the peritoneum with cancer cells, also called peritoneal carcinomatosis, is a dreaded complication of intestinal cancer.
Peritoneal carcinomatosis is caused by a local spread of the cancer cells and is usually seen in advanced cancer. Metastases in the head are not very common in colorectal cancer. However, brain metastases are particularly dangerous because they cause the displacement of brain tissue and thus lead to neurological deficits. Brain metastases usually occur in patients who have already had a long course of the disease and have metastases in several organs. In some cases, the metastases can be surgically removed; if this is not possible, radiation therapy may be considered.
