Metastasis can be defined as a disease process that involves the spread of cancer cells from the tissue or organ where they originated to more distant areas. Cancer cells that spread to other tissues generally retain the same characteristics as the cells from which they originated. For example, a cancer cell that has metastasized from the lung to the liver retains the properties of lung cancer cells.
What is Metastasis?
Metastasis is the spread of cancer from its original site to other parts of the body. Almost all cancers have the potential to metastasize. Whether this occurs depends on many factors, such as the type of cancer, its size, and the organ from which it originated.
How Does Metastasis Occur?
Metastasis occurs when cancer cells detach from their original location and spread to different areas of the body. The spread to different regions can occur through the bloodstream, lymphatic system, or direct neighboring pathways.
1- In hematogenous spread, cancer cells enter nearby newly formed or forming blood vessels and join the circulation, migrating to other parts of the body.
2- In lymphatic spread, cancer cells enter the lymphatic system and are transported to different lymph nodes, forming secondary tumors.
3- Another mechanism involved in the formation and spread of metastasis is transcoelomic metastasis. In this mechanism, existing tumors spread to adjacent tissues or organs through body cavities. Transcoelomic metastasis often occurs in pancreatic, colon, and uterine cancers.
Not all cancer cells survive in this process; only the strong and resilient ones can settle in other tissues. When cancer cells find a suitable microenvironment in the new tissues they reach, they settle and begin to grow. They form colonies in this new location, thus completing the metastasis. Although the settled cells have the genetic structure of the original tumor, they may alter their behavior according to the characteristics of the organ to which they have metastasized. The growth of metastatic cells in the new areas they invade is one of the most significant factors that complicates the treatment of common cancer cases. (3).
What are the Symptoms of Metastasis?
Metastasis does not always cause symptoms. The specific symptoms of metastasis are often unique to the area affected by the cancer. General symptoms of metastasis may include:
Fatigue
Another common symptom of metastatic cancer is extreme fatigue and weakness. The proliferation of cancer cells depletes the body’s energy resources, causing the patient to feel constantly exhausted. This fatigue can make even simple daily activities difficult. Additionally, depending on the organ where metastasis occurs, dysfunctions in organ functions can also increase fatigue.
Unexplained Weight Loss
Unexplained weight loss is a significant symptom of metastasis. The body loses energy while fighting cancer cells, which can lead to rapid weight loss. Moreover, cancer cells can secrete substances that cause loss of appetite, preventing the patient from consuming adequate nutrition. This weight loss typically develops suddenly and inexplicably.
Pain
The location and intensity of the pain can vary depending on the area where cancer has spread. Sometimes it is felt only with movement, while at other times it is a constant discomfort. Particularly, bone metastasis can lead to severe and persistent pain in the bones. This pain occurs as a result of cancer cells weakening the bone and destroying bone tissue.
Shortness of Breath
In cancers that have metastasized to the lungs, shortness of breath is a common symptom. Cancer cells invade lung tissue, disrupting the normal functions of the lungs. This condition can make breathing difficult and cause a constant feeling of respiratory distress in the patient. Metastasis can also lead to fluid accumulation around the lungs, exacerbating this symptom.
Neurological Symptoms
In cancers that have spread to the brain, neurological symptoms such as headaches, blurred vision, and dizziness may be observed. Brain metastasis causes these types of symptoms by exerting pressure on brain tissue. The patient may experience cognitive impairments, memory loss, and difficulty concentrating. In more advanced cases of the disease, seizures and stroke-like symptoms may occur.
Jaundice
Patients with liver metastasis may exhibit jaundice. Jaundice occurs due to elevated bilirubin levels resulting from impaired liver function. This symptom manifests as yellowing of the skin and eyes. Abdominal pain and swelling are also commonly seen in patients with liver metastasis.
How is Metastasis Diagnosed?
The first step in diagnosing metastasis is taking the patient’s history. The doctor collects information about symptoms, the starting point of the cancer, and the likelihood of spread by listening to the patient’s detailed medical history. For example, newly emerging persistent bone pain, shortness of breath, or sudden weight loss may indicate metastasis.
After taking the patient’s history, a physical examination is performed. During the physical examination, the doctor checks the body to assess the patient’s overall health and look for signs of metastasis. Particularly, signs such as swelling, hardness, or abnormal masses may indicate metastatic cancer. Some tests used for the definitive diagnosis of metastasis include:
Blood Tests
Abnormalities indicating impaired organ function can be seen in blood tests, especially in liver and bone metastases. Specific proteins produced by cancer and tumor markers can provide clues about the presence of metastasis. These tests can also provide information about which organs metastasis may have spread to.
Imaging Techniques
Various imaging techniques are used to diagnose the spread of metastasis. Computed tomography (CT) and magnetic resonance imaging (MRI) show in detail where cancer has spread in the body. Positron emission tomography (PET) detects areas of metastasis by evaluating the metabolic activity of cancer cells. Bone scans are specifically used to diagnose bone metastases and show whether cancer has spread to the bones.
Biopsy
Taking a tissue sample from a suspicious area and examining it in a pathology laboratory is one of the most reliable methods used for the definitive diagnosis of metastasis. A biopsy is important for determining which organ the metastatic cancer cells originated from and whether the characteristics of the initial cancer have changed. This procedure is usually performed by inserting a needle into the cancerous area or through surgical intervention. Biopsy results confirm the diagnosis of metastatic cancer and shape the treatment plan(4).
What are the Treatment Methods for Metastasis?
The patient’s overall health status, the origin of the cancer, and the degree of spread are among the factors that influence the choice of treatment method. Treatments for metastatic cancer may include:
- Chemotherapy,
- Immunotherapy,
- Targeted therapy,
- Hormone therapy,
- Radiation therapy,
- Surgical intervention
Chemotherapy: Chemotherapy targets rapidly dividing cancer cells and attempts to destroy them. Chemotherapy drugs circulate through the body via the bloodstream, reaching metastatic cancer cells and leading to their death.
Immunotherapy: Activates the body’s immune system against cancer. These types of drugs help immune cells recognize and destroy cancer cells.
Targeted therapy drugs: Focus on the genetic structure of cancer cells or specific proteins on their surface. They provide treatment by targeting specific mutations that enable cancer cells to grow.
Hormone therapy drugs: Especially in hormone-sensitive cancers, drugs that reduce hormone production or block the effects of hormones are used. These drugs can suppress the hormones necessary for the growth of cancer cells, halting the progression of metastasis.
What is the Prognosis in the Case of Metastasis?
The prognosis created by this condition depends on many factors, such as the type of cancer, the degree of spread, and the response to treatment. The treatment of a cancer that has metastasized can often be challenging and indicates that the disease is in an advanced stage. Some metastases may respond well to treatment, and the patient’s lifespan can be extended with treatment. Treatment options are shaped according to the patient’s overall health status and which organs metastasis has spread to. In cases of metastasis that are diagnosed early and can be treated, the quality of life can be improved, and the chance of controlling cancer may increase.
Frequently Asked Questions
1-Where is metastasis commonly seen?
Metastasis can occur in different organs in the body depending on the type of cancer. Common target organs for metastasis include the lungs, liver, bones, and brain.
2-Is early recognition of metastasis possible?
Early recognition of metastasis may be possible with regular screenings and careful monitoring of cancer progression. Especially in individuals diagnosed with cancer, it is important to conduct follow-up tests against the risk of metastasis.
3-Is surgical intervention necessary in the treatment of metastasis? If so, when should it be performed?
This treatment method should be preferred in some types of cancer and when metastasis is limited to one organ and the disease has been controlled with systemic treatments. However, it may be preferred especially if metastatic cancer tissue exerts pressure on vital organs or causes significant functional loss in a specific organ.
4-Can chemotherapy stop metastasis?
Chemotherapy can stop or slow the growth of metastatic cancer cells. This treatment method aims to reach tumors in the body through the bloodstream and destroy them. However, it may not be effective in every case of metastasis.
5-Is there a risk of recurrence of metastasis?
Even if metastases completely disappear with the treatments applied, there is always a risk of recurrence in the same place or in another part of the body. Regular monitoring, follow-up, and maintenance treatments are important in reducing the risk of metastasis reappearing.
6-What are the symptoms of metastasis?
The symptoms of metastasis vary according to the organ to which cancer has spread. General symptoms include fatigue, unexplained weight loss, and loss of appetite, among other common symptoms (4).
7-How is the diagnosis of metastasis made?
The diagnosis of metastasis is usually made through imaging tests (PET, MRI, CT scans) and biopsy. Blood tests can also provide insights into whether metastasis has occurred (4).
8-How long does metastasis treatment take?
The duration of treatment varies depending on the spread of cancer and the treatment method. Treatments such as chemotherapy, radiation therapy, or surgery can take months and may sometimes require lifelong treatment and follow-up. The treatment process focuses on controlling cancer or managing symptoms.
9-Can metastasis be treated with natural methods?
Currently, there are no known and medically applied natural treatment methods for cancer. The primary medical methods used in treatment are chemotherapy, immunotherapy, targeted therapy, hormone therapy, radiation therapy, and surgical intervention (1).
10-Can metastasis occur while receiving chemotherapy?
The risk of developing metastasis does not completely disappear while receiving treatment. Although chemotherapy aims to stop the spread of cancer cells, not every patient responds to treatment in the same way. Unfortunately, during treatment, cancer cells may develop resistance to drugs, and metastasis may occur.
