Metastasis Cancer

Metastasis Cancer (abbreviated mets), is the spread of a disease from one organ or part to another non-adjacent organ or part. It was previously thought that only malignant tumor cells and infections have the capacity to metastasize; however, this is being reconsidered due to new research.

Cancer occurs after a single cell in a tissue is progressively genetically damaged to produce a cancer stem cell possessing a malignant phenotype. These cancer stem cells are able to undergo uncontrolled abnormal mitosis, which serves to increase the total number of cancer cells at that location. When the area of cancer cells at the originating site becomes clinically detectable, it is called a primary tumor.

Some cancer cells also acquire the ability to penetrate and infiltrate surrounding normal tissues in the local area, forming a new tumor. The newly formed "daughter" tumor in the adjacent site within the tissue is called a local metastasis.

Some cancer cells acquire the ability to penetrate the walls of lymphatic and/or blood vessels, after which they are able to circulate through the bloodstream (circulating tumor cells) to other sites and tissues in the body. This process is known as lymphatic or hematogeneous spread.

After the tumor cells come to rest at another site, they re-penetrate through the vessel or walls, continue to multiply, and eventually another clinically detectable tumor is formed. This new tumor is known as a metastatic tumor. Metastasis is one of three hallmarks of malignancy. Most tumors and other neoplasms can metastasize, although in varying degrees (e.g. basal cell carcinoma) rarely metastasize.

When tumor cells metastasize, the new tumor is called a secondary or metastatic tumor, and its cells are like those in the original tumor. This means, for example, that, if breast cancer metastasizes to the lungs, the secondary tumor is made up of abnormal breast cells, not of abnormal lung cells. The tumor in the lung is then called metastatic breast cancer, not lung cancer.

The symptoms of metastasis varies with location of the tumors.Initially, nearby lymph nodes are struck early. Lungs, bones, liver, and brain are the most common metastasis locations from solid tumors.

• In lymph nodes, a common symptom is lymphadenopathy
• Lungs: cough, hemoptysis and dyspnea (shortness of breath)
• Liver: hepatomegaly (enlarged liver) and jaundice
• Bones: bone pain, fracture of affected bones
• Brain: neurological symptoms such as headaches, seizures, and vertigo.

Although advanced cancer may cause pain, it is often not the first symptom. Some patients, however, don't show any symptoms.

article source: wikipedia