Cryoablation of Human Colorectal Cancerin Vivoin a Nude Mouse Xenograft Model

Abstract Objective: To establish the minimum required temperature in cryoablation of human colorectal cancer cell lines grown as subcutaneous tumors in mice. Methods: Male nu/nu nude mice were inoculated by a sc injection of 1 × 10 6 LoVo ( n = 30) or C170 ( n = 32) cells. After 2 weeks the tumors were frozen using a 3-mm cryotherapy probe (LCS 3000, Cryotech, UK) to temperatures ranging from −8 to −84°C. Results: (LoVo) Of 21 mice evaluable for analysis no tumors recurred in 3 mice which had their tumors frozen to less than −60°C as measured at the presumed tumor/host boundary, whereas all but one tumor recurred in 18 mice which had their tumors frozen to >−60°C. (C170) Of 18 mice evaluabl…