How It Spreads Metastases spread in three ways—by local extension from the tumor to the surrounding tissues, through the bloodstream to distant sites or through the lymphatic system to neighboring or distant lymph nodes . Each kind of cancer may have a typical route of spread. The most likely sites of metastases for each tumor are listed in the individual tumor sections.
What Causes It The characteristics of each tumor are different, and it is not known what factors make the metastasis develop in particular places.
