What Does Metastasis Mean?
Metastasis is the spread of cancer cells from their formation site to another part of the body. In metastasis, cancer cells travel through the blood or lymph system after they break away from the primary tumor. Then, the metastasizing cells form a new tumor in other organs or tissues of the body. Metastasis can occur in mesothelioma patients if malignant cells in a tumor lining the lungs break off and spread through the lymph nodes to other sites.
When Does Mesothelioma Metastasizse?
Mesothelioma metastasis depends on the cell type, stage of cancer, and other factors. It can occur locally, regionally, or distantly. The stage of cancer also determines how much it has spread from the original site of occurrence when a patient first receives a diagnosis. The mesothelioma staging system consists of stages 1, 2, 3, and 4. Up to half of stage 4 mesothelioma patients experience the spread of cancer distantly, meaning the mesothelioma has spread further than the pleural or thoracic cavity. Patients in earlier stages (1, 2, and 3) typically experience regional metastasis, where cancer spreads within the nearby lymph nodes. Local metastasis happens when cancer cells spread within the cavity where mesothelioma first occurs.
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Patients living with stage 1 or stage 2 mesothelioma are given the best prognosis while patients diagnosed with stage 3 or stage 4 may already be experiencing distant metastasis. At one point in time, doctors thought pleural mesothelioma was localized cancer, meaning metastasis did not occur outside of the pleural cavity. More than half of pleural mesothelioma patients experience some form of metastasis. Stages of mesothelioma are not the only factor that may influence progression. The cellular makeup of a mesothelioma tumor can also determine how much it can grow and spread. Tumors with a sarcomatoid or biphasic cellular makeup for instance, spread rather quickly to distant areas. Epithelial mesothelioma cells, however, spread slower. The life expectancy for patients with epithelial mesothelioma cells generally exceeds patients with other cell types.
What Are The Symptoms of Metastatic Mesothelioma?
In addition to the many complications from mesothelioma, the spread of it causes further symptoms. Doctors suspect cancer metastasizes when a patient experiences symptoms not associated with mesothelioma. Some symptoms of metastasis can appear to be similar to average mesothelioma symptoms. Depending on where mesothelioma spreads, different symptoms may appear. Mesothelioma metastasis typically occurs in the liver, kidneys, adrenal glands, spleen, or the opposite lung. Although extremely rare, mesothelioma can also spread to the brain.
The liver is an organ located in the upper right portion of the abdominal cavity. As a regulator of most chemical levels in the blood, the liver breaks down, balances, and creates the nutrients in the blood. Symptoms of mesothelioma metastasis to the liver include:
The adrenal glands are located on the top of the kidneys. The purpose of the adrenal glands is to produce hormones that regulate the metabolism, immune system, blood pressure, and response to stress. Symptoms of mesothelioma metastasis to the adrenal glands include:
The kidneys are located on either side of the spine below the rib cage. Some of the functions of the kidneys include the removal of waste, toxins, and excess water from the bloodstream. Mesothelioma patients may experience these symptoms if cancer spreads to the kidneys:
The spleen is located on the left side of the abdomen, next to the stomach. Although people can survive without a liver, the spleen provides an extra defense for germs attempting to invade the blood. Symptoms of mesothelioma spread to the spleen include:
Although rare, mesothelioma has spread to the brain in a few cases. The brain, located inside the skull, controls thought, emotion, memory, touch, motor skills, and many other regulatory functions. Symptoms of mesothelioma spread to the brain include:
Detecting Symptoms of Mesothelioma Metastasis
Doctors can detect the spread of mesothelioma through diagnostic imaging scans. The imaging tests typically consist of PET or CT scans and MRIs. Additionally, a patient may undergo a biopsy to determine where the cancer has spread.
Where Does Mesothelioma Metastasize?
Mesothelioma metastasis occurs when cancer cells spread through the lymph nodes. Eventually, the cells reach the bloodstream through a process called angiogenesis, which is the formation of new blood vessels. Depending on the site of mesothelioma, cancer often spreads to nearby organs and tissues.
Pleural Mesothelioma Metastasis
Historically, researchers and doctors thought pleural mesothelioma was a localized disease and did not metastasize to other parts of the body. However, statistics from studies say up to 50 percent of mesothelioma patients experience metastasis. Pleural mesothelioma metastasizes most often to the liver, adrenal glands, kidneys, and the opposite lung.
Peritoneal Mesothelioma Metastasis
Peritoneal mesothelioma patients generally have a better life expectancy than those with pleural mesothelioma. Besides responding better to treatments compared to pleural mesothelioma, peritoneal mesothelioma does not typically progress to cavities outside the peritoneal cavity. The peritoneal cavity contains the peritoneal lining, stomach, liver, intestines, and spleen. This form of mesothelioma can also spread to abdominal lymph nodes.
In rare cases, peritoneal mesothelioma can metastasize to other areas, including:
- Adrenal glands
- Soft tissue
Pericardial & Testicular Metastasis
Pericardial mesothelioma forms in the lining of the heart called the peritoneum. This site of mesothelioma is extremely rare, with less than 500 new cases each year. Pericardial mesothelioma can metastasize to the pleura, lungs, regional lymph nodes, and kidneys. Testicular mesothelioma rarely metastasizes, but can progress into regional lymph nodes, inguinal and iliac lymph nodes, thoracic and lumbar vertebrae, omentum, liver, and lungs.
How Does Mesothelioma Metastasis Affect The Body?
Mesothelioma most commonly metastasizes to the liver, spleen, kidneys, and adrenal glands. In rare cases, mesothelioma metastasis to the brain can occur. However, only about 3 percent of mesothelioma cases spread to the brain or central nervous system. In very rare cases, mesothelioma metastasis to bone can occur.
Mesothelioma Metastasis Treatment Options
Although there are new and upcoming diagnosis approaches, such as using blood tests to diagnose mesothelioma, patients typically receive a diagnosis in later stages, after metastasis occurs. Depending on the stage of cancer, patients may be eligible for curative or palliate treatments. Curative treatment methods such as surgery and radiation therapy are most successful in patients with stages I-III mesothelioma.
Aggressive treatments options are often too invasive for someone with stage IV mesothelioma. Instead, late-stage patients can benefit from palliate treatments to reduce painful symptoms. Surgery, radiation, and chemotherapy are commonly used as palliative methods to remove or shrink tumors pressing against nerves. Mesothelioma metastasis treatment options may also include steroids and pain medicine to increase comfort during the course of their cancer fight.