The Different Types of Metastases

Not all types of metastasis are the same. Let's look at its most frequent manifestations and the ways in which malignant cells can spread.

Metastatic cancer is one that develops far from the initial process of malignant cell multiplication. These break away from their initial host and travel through the body to form new tumors. According to these two characteristics (transport route and final destination) we can identify various types of metastases.

It’s important to remember that metastatic tumors are the same as primary cancer. That is, if a person with colon cancer causes metastases in the lung, they are not considered to have lung cancer.

It will be called, in this example case, metastatic colon cancer. This applies to all contexts.

Types of metastases by their dissemination

When specialists talk about types of metastases, they usually refer to the area of secondary spread of the malignant cells. Although in theory they can spread to any part of the body, in practice some areas are more favored than others.

Researchers agree that the most common areas are the bones, lung, liver, and brain. The lymph nodes, in turn, usually represent the first host site after the cells travel.

Bone metastasis

According to the National Cancer Institute, bone metastasis is the most common type in most dissemination processes. It can occur in almost all types of cancer, although it’s more common in the following:

• Bladder
• Breast
• Colon
• Kidney
• Lung
• Skin cancer
• Prostate
• Thyroid
• Uterus

Evidence tells us that most bone metastases can’t be cured, although there are treatment options to slow their growth. This spreading process is more common than primary bone cancer, especially in the adult population.

It’s classified, in turn, into three subtypes:

• Osteolytic: This is characterized by the destruction of normal bone.
• Osteoblastic: This is distinguished by the deposit of new bone material. It’s also known as sclerotic bone metastasis.
• Mixed: In these cases, the patient develops both processes.

Bone pain is its main symptom. Although it depends on the characteristics of each patient, an average survival of 20 months is estimated.

Liver metastasis

Studies in this regard indicate that 25% of metastases occur in the liver. Most cases are caused by colorectal cancer, although of course liver metastasis is also possible in other types of primary cancers.

As with the previous case, processes of this type are more common than primary liver cancers. This is because the abundant blood supply in the organ makes it easier for cells to travel once they begin to spread.

Lung metastasis

According to the evidence, up to 20% of the metastases reported each year correspond to the lungs. The average life expectancy after detection is around 5 years. This depends on the characteristics of the tumor and how advanced it is at the time of diagnosis.

People are not likely to notice symptoms warning of this spread. When they appear, and following UCLA Health, you may experience the following:

• Pain in the rib cage
• Bloody sputum
• Difficulty breathing
• Coughing

Surgical removal of tumors is often not feasible, as malignant cells are most often present in places that cannot be seen by imaging tests. Chemotherapy, in this sense, is the most widely used option.

Brain metastasis

It is estimated that between 10% and 26% of patients with metastases develop cancer cells in the brain. It may take years for this type of metastasis to develop.

They are more common in older patients, especially those over 65 years of age. They don’t generate symptoms until growth begins to interfere with brain function.

Following Johns Hopkins Medicine, in these contexts you state the following:

• Headaches
• Memory loss
• Seizures
• Difficulty in speech
• Weakness in the arms and legs
• Lack of coordination

Surgery is a viable option for these types of metastases, especially to reduce or alleviate some of the symptoms reported. The most used is the craniotomy, although there are other options that are adjusted according to the case.

Lymph node metastasis

Since the lymphatic system is one of the transport routes that cancer cells can use to spread, they can end up in the lymph nodes. It’s more common for them to do so in the lymph nodes near the tumor, since these are the ones that do the most work when trying to remove them.

Types of metastases by their transport route

The division of the anterior metastasis types is the most common when determining the spread of a primary cancer. In turn, and although it isn’t part of the standard division, it’s sometimes classified according to the transport route used for the travel of malignant cells.

Circulatory system

This variant is known as hematogenous spread and can occur through arteries or veins. Most of the time the cells die during the process, although those that survive install themselves in areas far from the initial area.

Lymphatic system

As we have already told you, cells can also use lymphatic spread. These cases often lead to tumors in the lymph nodes, although the metastasis may also spread to other areas of the body.

Body wall

This is also known as transcoelomic dissemination that which occurs by continuity of the tissues. In these cases, the malignant cells travel through the pleural, subarachnoid, peritoneal, or pericardial spaces. After this, they find an area to stay and begin to grow.

The types of metastases can be combined

The spread of cancer doesn’t have to focus on just one type of metastasis. Sometimes cells can lodge in more than one area and begin to multiply. These cases generally can’t be treated.

Keep in mind that if you experience any of the symptoms we’ve outlined, it isn’t an unequivocal sign that you’re going through a metastasis. The diagnosis can only be made by a professional, so you must adhere to their recommendations.