Cryoablation of human colorectal cancer in vivo in a nude mouse xenograft model.
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 x 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 degreesC.


RESULTS
(LoVo) Of 21 mice evaluable for analysis no tumors recurred in 3 mice which had their tumors frozen to less than -60 degreesC as measured at the presumed tumor/host boundary, whereas all but one tumor recurred in 18 mice which had their tumors frozen to >-60 degreesC. (C170) Of 18 mice evaluable for analysis 14 mice which had their tumors frozen to between -8 and -84 degreesC as measured at the presumed tumor/host boundary developed tumor recurrence. Four mice which had their tumors frozen to -11, -58, -62, and -81 degreesC did not develop tumor recurrence.


CONCLUSIONS
Cryotherapy of subcutaneous human colon cancer xenografts in nude mice results in tumor recurrence if tumors are frozen to temperatures of as low as -60 degreesC (LoVo) or -84 degreesC (C170) with a single freeze-thaw cycle. A critical temperature for the effective cryoablation of human colorectal cancer cell lines grown as subcutaneous tumors in mice with a single freeze-thaw cycle was not defined.
Department of Surgery, St. George Hospital, University of New South Wales, Kogarah, Sydney, New South Wales, 2217, Australia.
J K
JK
Seifert
J
J
Zhao
J
J
Ahkter
E
E
Bolton
T
T
Junginger
D L
DL
Morris
D000818:Animals; D003080:Cold Temperature; D015179:Colorectal Neoplasms / Q000473:pathology* / Q000628:therapy*; D017679:Cryotherapy; D006801:Humans; D008297:Male; D051379:Mice; D008819:Mice, Nude; D009368:Neoplasm Transplantation; D009374:Neoplasms, Experimental / Q000473:pathology* / Q000628:therapy*; D014183:Transplantation, Heterologous