CRITICAL-TEMPERATURE FOR IN-VIVO CRYOABLATION OF HUMAN PROSTATE-CANCER IN A XENOGRAFT MODEL

Objectives To assess the in vivo sensitivity of human prostate cancer cells (PC3) to cryoablation and thus define the minimum temperature ne eded to prevent the recurrence of cancer after percutaneous transperin eal radical prostatic cryoablation, Materials and methods Twenty-five male nu/nu mice were inoculated by a subcutaneous injection with 5 x 1 0(5) PC3 cells. After 3 weeks the tumours (mean area 60.4 mm(2), SEM 5 .7) were frozen using a 3 mm cryotherapy probe (LCS 3000 Cryotech UK) to temperatures ranging from O degrees to -40 degrees C. Results No tu mours recurred in seven mice which had tumours frozen to < -15 degrees C, There were eight recurrences in 15 mice which had tumours frozen t o between 0 degrees and -15 degrees C, and all were confirmed histolog ically. Conclusions The minimum temperature required to prevent recurr ence of tumours from human prostate cancer cells was < -15 degrees C i n this in vivo mouse model.