癌扩散(2)【沪江慢速VOA 4-08】
Metastasis: How Cancers Can Spread Their Reach (2/2)
Doctors removed Mister Snow's cancerous colon in 2005. He had chemotherapy for 6 months.
Most metastatic cancers are incurable. But most also are treatable. Chemotherapy drugs, radiation and other treatments can extend a patient's life.
Life expectancies differ depending on the kind of cancer, the affected organ and other issues. Some research shows that only about 25% of newly discovered metastatic breast cancer patients live for 5 years. The average life expectancy for metastatic colon cancer patients is about 2 years. Doctors say chances are worse for patients 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 announced a finding that may help in the fight against metastasis. They said the same enzyme that controls the ability of cancer cells to metastasize also controls the process that keeps them stuck tightly together.
