The mechanical spread of viable tumor during surgery.

The "mechanical" spread of tumor is that which occurs through physical trauma, such as during surgical resection. There has been a waxing and waning of interest in this concept over the past 70 years. We have collected the blood that comes off the surgical field during major head and neck resections and separated and plated all nucleated cells in the tumor stem cell assay of Hamburger and Salmon. In one of six such preparations, we demonstrated the presence of viable, colony-forming tumor cells. Two were contaminated and three did not grow. We demonstrated, therefore, that the blood that bathes the raw open surgical field contains tumor cells that are viable and potentially capable of producing new foci of tumor.