Soon after arriving in Dallas, however, Thorpe decided he wanted to focus on solid tumors, essentially all malignancies except lymphomas and leukemias. To his inquisitive mind, solid tumors were more of a challenge. Solid tumors are more deadly and more common, especially non-small cell lung cancer. Solid tumors also are more difficult to kill. They are less permeable and less accessible to intravenously administered drugs, such as chemotherapy and immunotoxins.
Cancer cells are chameleons.
They change form, or mutate, so a drug that may kill off some of the malignancy often loses its effectiveness. Thorpe decided to find a way around these obstacles, and he remembers when the idea struck him to coagulate the tumor's blood supply. Next, I began trying to think of a new way to attack tumor cells. Thorpe set out to explore this approach. The advantage of this is that the flat endothelial cells lining a blood vessel are easily accessible to drugs, and, because they are normal cells, they won't mutate and become resistant to treatment.