BACKGROUND: We sought to determine whether more than one freeze/thaw cycle is required and what minimum temperature reliably kills prostate cancer in vivo. METHODS: Two human prostate cancer cell lines (LNCaP and PC3) were implanted subcutaneously in male nude BALB/c mice. Tumors were frozen with contemporary cryosurgery equipment and monitored for temperature, size, and serum prostate-specific antigen (PSA) measurements. The tumors were subjected to one or two freeze/thaw cycles through a wide range of temperatures from 0 - -80 degrees C. RESULTS: These experiments show that a single freeze/thaw to a temperature < -40 degrees C is adequate to kill most tumor cells in this mouse model of prostate cancer. CONCLUSIONS: Freezing prostate cancer to < -40 degrees C and ensuring that the entire tumor is frozen is more important than additional freeze/thaw cycles in this experimental model.
BACKGROUND: We sought to determine whether more than one freeze/thaw cycle is required and what minimum temperature reliably kills prostate cancer in vivo. METHODS: Two humanprostate cancer cell lines (LNCaP and PC3) were implanted subcutaneously in male nude BALB/c mice. Tumors were frozen with contemporary cryosurgery equipment and monitored for temperature, size, and serum prostate-specific antigen (PSA) measurements. The tumors were subjected to one or two freeze/thaw cycles through a wide range of temperatures from 0 - -80 degrees C. RESULTS: These experiments show that a single freeze/thaw to a temperature < -40 degrees C is adequate to kill most tumor cells in this mouse model of prostate cancer. CONCLUSIONS:Freezing prostate cancer to < -40 degrees C and ensuring that the entire tumor is frozen is more important than additional freeze/thaw cycles in this experimental model.