This is the VOA Special English Health Report.

The word "metastasize" means to change form, state or position. It is not a word cancer patients want to hear.

Cancer can spread in a body two ways. As a grows it may invade neighboring tissue or organs. Or, cancer can . This is when cancer cells break away from a first tumor and travel through blood or the lymphatic system. The cells then grow in another part of the body. Not all spread to other parts of the body after they are treated.

However, last month, two well-known Americans announced that their cancers had .

Elizabeth Edwards, wife of Democratic Party presidential candidate, John Edwards, said her breast cancer had to her bones.

The next week the White House announced that Press Secretary Tony Snow's cancer had moved to his liver. The White House noted that the cancer was not in his but attached to it.

Missus Edwards’ breast cancer was discovered in two thousand four. She was treated for several months with drugs to shrink the tumor. Then doctors removed it. The lumpectomy operation was followed with treatments to kill any remaining cancer cells.

Doctors removed Mister Snow's cancerous colon in two thousand five. He had chemotherapy for six months.

Most metastatic cancers are . But most also are treatable. Chemotherapy drugs, radiation and other treatments can a patient’s life.

Life expectancies differ depending on the kind of cancer, the affected and other issues. Some research shows that only about twenty-five percent of newly metastatic breast cancer patients live for five years. The average life expectancy for metastatic colon cancer patients is about two years. Doctors say chances are worse for whose cancer is not found until after it has already metastasized.

But doctors say they can only guess how long any person may live with metastatic disease. In February, American and Canadian researchers a finding that may help in the fight against metastasis. They said the same that controls the ability of cancer cells to metastasize also controls the process that keeps them stuck together.