Despite cancer cells frequently being found in the blood of early-stage lung and breast cancer patients, metastasis to distant sites is relatively rare.

“human cancers are frequently dumping millions of cells into the blood and aesthetic sites metastasis are are relatively rare when you think that you know people with early stage lung cancer you know you can find cancer cells in their bone marrow and yet they don't get bone marrow metastasis breast cancer is the same kind of thing you can do bone marrow biopsies on women getting mastectomies for apparently localized disease and maybe 30 to 40 of them will have breast cancer cells in their bone marrow and yet all of them do not develop um you know metastatic disease in the bones”

“when you think that you know people with early stage lung cancer you know you can find cancer cells in their bone marrow and yet they don't get bone marrow metastasis breast cancer is the same kind of thing you um you can do bone marrow biopsies on women getting mastectomies for apparently localized disease and maybe 30 to 40% of them will have breast cancer cells in their body bone marrow and yet all of them do not develop um you know metastatic disease in the bones thank thank goodness”