Cancer is a disease that claims millions of lives every year. Metastasis is the most serious complication that can occur in this clinical picture.
“Cancer” is the name given to a group of related diseases. In all existing types, some of the patient’s cells begin to divide without stopping (which produces the tumor) and end up spreading to other places (metastasis). A carcinogenic process can begin in almost any part of the human body.
Undoubtedly, this definition does not do justice to the fear and suffering that this pathology produces in the general population. Almost all of us have lost a loved one to carcinogenic processes, as the World Health Organization (WHO) estimates that 1 in 6 deaths worldwide are due to this disease. This translates, approximately, to about 8.8 million deaths per year.
Anyway, if there is a term with more negative connotations than cancer itself, it is metastasis. This is the word that no patient wants to hear, because in some types of metastatic cancers such as bone cancer, the survival rate is less than 30% 4 years after diagnosis. As unpleasant as this topic may be, our duty is to inform the population: today we present the 6 types of metastasis.
- We recommend you read: “The 7 cancer treatments (and their characteristics)”
What is metastasis?
First and foremost, we want to emphasize that the diagnosis of cancer is not the end of the road. Depending on the type, location, and stage of detection, the chances of recovery vary widely. Here we are putting ourselves in the worst of the worst: the phase of no return.
Metastasis is defined as the process of spreading from a cancerous focus (usually through blood or lymph) to an organ other than the one in which it began. It should be noted that a metastatic tumor is of the same type as the primary. For example, a metastatic tumor in the lung resulting from breast cancer has breast cancer cells, not lung cancer cells.
It is estimated that92% of deaths from untreated cancers are due to metastasizing ofthese, as there is usually no possible cure for this event. In general, the treatment is aimed at extending the patient’s life as long as possible as long as it can be dignified.
What are the types of metastasis?
Once we have defined the term and presented some relevant statistics, it is time to look at the 6 types of metastasis. These are generally classified according to the means of dissemination.
1. Lymphogenic metastasis
The lymphatic system plays an essential role in transporting fluids through the body, as it transports lymph, a colorless liquid containing oxygen, sugars, proteins and lymphocytes. This fluid “highway” is designed for the entry and exit of cells of an immune nature, which is why it is easy for cancer cells to enter it.
For this reason, lymphogenic metastasis is the most common type of all. Once the cancer cells penetrate the lymphatic vessels, they are transported with the lymph to a regional lymph node. They can settle there forming a lymph node tumor (lymph node metastasis), but they can also travel and colonize other nodes or more distal organs.
It should be noted that these movements of cancer cells usually occur at the rhythm of the lymphatic stream. Therefore, in breast cancer the first lymphogenic metastases are sought in the nodes of the armpit, as it is “the first stop” possible for tumor cells. Even so, the drainage routes of a tumor are diverse and, therefore, up to 30% of them cannot predict which node will be affected in the metastasis.
2. Hematogenous metastases
As its name suggests, in this case it is the circulatory system that transports tumor cells. We do not want to get lost in specific terminology, which is why we will limit ourselves to saying that tumor cellsgive rise to a tumor embolus in blood vesselsand that, in experimental models, 99.9% of these pathogenic cells are destroyed. Unfortunately, the patient is not so lucky in all cases.
Depending on the primary tumor, several types of hematogenous metastatic distribution are distinguished. We name them below:
2.1 Lung model
The tumor is located in the lung andmetastatic cells will travel to the heart through the pulmonary veins. From here they can be moved to virtually any organ.
2.2 Cava model
The tumor that will lead to metastasis is locatedin an organ or tissue that “flows” into the vena cava. Due to human physiology and blood flow pattern, metastatic tumor is expected to develop in the lung. It should be noted that the lung is the second most common site of metastasis throughout the body, encompassing all histological types (up to 30% of cases).
2.3 Holder model
The Porta systems (branching of irrigation pathways into small ducts) are described in different organs such as the liver, the hypothalamic-pituitary system and in the kidney. Therefore, this model is applied in tumors that are located in an organ dependent on a Portal system, such asthe ascending colon or pancreas.
2.4 Vertebral veins model
This typology is defined by very complex terms. We will limit ourselves to saying that the tumor spreads through aninverted blood flow directed to the vertebral veins, which is due to an increase in intrathoracic or intra-abdominal pressure due to specific events.
3. Transcellomic metastases
In this case, the means of transport of metastatic cells is neither the lymphatic nor the circulatory system, but occurs through the fluid of a serous cavity or cerebrospinal fluid, that is, through the mucous membranes of the body, so the dissemination is to nearby organs or tissues.
In general, metastases are usually peritoneal, that is, they are located in the membrane that covers the inner wall of the abdomen and some organs of the abdomen, such as the stomach, intestine or colon. It is also common for a lung tumor to pass into the pleura.
Not all cancers end with metastases
Again, we want to emphasize thatmetastasis is by no means the outcome of all carcinogenic processes. For example, if a breast cancer is found in only one of the two breasts, the survival rate for patients is 99%. Another hopeful example is that of colorectal cancer, because if the tumor is localized and successfully removed, the 5-year survival rate is 90%.
In addition to this, the World Health Organization (WHO) gives us the following essential mention data:
- Approximately one-third of fatal carcinogenic processes are attributed to tobacco and alcohol use, obesity, and an unhealthy lifestyle.
- Smoking is the main risk factor, causing 22% of cancer deaths. Tobacco kills up to almost half of the people who use it.
- Lung cancer causes the most deaths of all, followed by liver, colorectal, gastric and breast cancer.
It is not surprising to anyone to learn that lung cancer is associated with tobacco, liver cancer, alcoholism and colon cancer, obesity. The correlation can be more or less direct according to each type, but one thing is clear to us: our lifestyle increases or decreases the chances of suffering from cancer whether you like to recognize it or not.
In addition, it is believed that only about 5-10% of cancers are caused by genetic defects inherited from one of the two parents. Although the causes of many of these processes are not yet fully known, it is clear that the environment and lifestyle play a much more relevant role than family inheritance in their appearance. As long as it is diagnosed early and treatments are applied quickly, metastasis does not have to arise.
Summary
We have presented the 6 main types of metastases of metastases according to the means of transport of the metastatic cells: lymphogenically, hematogenous or transcellomic. Although lymphogenic is the most common of all, each of the variants named here has its particularities and medical importance.
Anyway, we want to emphasize the last message provided in the bulk of the text: many cancers are inevitable, but many others can be prevented with a good lifestyle. Take care of yourself today so you don’t suffer tomorrow.
To the classic question “what do you do?” I always answer “basically I am a psychologist”. In fact, my academic training has revolved around the psychology of development, education and community, a field of study influenced my volunteer activities, as well as my first work experiences in personal services.
